The radiation hybrid database

The objective of this study was to evaluate morphological characteristics and testicular function of boars with different endogenous concentrations of FSH. Boars were selected at 6 mo of age on the basis of mean FSH concentrations in plasma collected at 4, 5, and 6 mo of age. Boars were classified within half-sibling families based on whether they had high concentrations of FSH (HiFSH, > 500 ng/ml, n = 9) or low concentrations (LoFSH, < 500 ng/ml, n = 7). At 14.5 mo, testes were collected, fixed, sectioned at 1 microm, and evaluated for morphological characteristics. Boars with LoFSH had larger (p < 0.01) testicular and epididymal weights than boars with HiFSH, greater (p < 0.01) daily sperm production per gram of testis, and greater total daily sperm production per boar. Testes of boars with LoFSH had a greater (p < 0.03) volume percentage of seminiferous tubules, a lesser percentage (p < 0.03) of Leydig cells, and a somewhat lesser (p = 0.06) percentage of vascular structures than testes of boars with HiFSH. Testes of boars with LoFSH had greater (p < 0.01) total tubule volume and tubule length than testes of boars with HiFSH. There were no differences (p > 0.70) in volume, diameter, or total number of Leydig cells or in total interstitial volume in testes (p > 0.41) of these two groups. Production of testosterone in vitro per paired testis and per million Leydig cells was not different (p > 0.65) between boars with HiFSH or LoFSH. Greater concentrations of FSH in blood plasma were negatively associated with development of seminiferous tubules and spermatogenic efficiency, whereas Leydig cell development was not different in boars of these two groups.     

Testing the potential of sodium fluoride to affect spermatogenesis: a morphometric study

This study provides quantitative information on the effect of sodium fluoride (NaF) on the testes of F1 generation male rats exposed in utero and during lactation to NaF at one of four concentrations (25, 100, 175, 250 ppm). At weaning, the F1 generation males were exposed to NaF in their drinking water for 14 weeks, after which time testicular tissues were perfusion-fixed with glutaraldehyde and observed after being embedded in plastic. The seminiferous tubules comprised 89%, 87%, 88%, 88% and 88% of the total testis volume while the interstitial space occupied 9.3%, 11.2%, 10.2%, 9.8% and 9.9% of the total testis volume for the 0, 25, 100, 175 and 250 ppm NaF treatment groups, respectively. Statistically significant differences between control and NaF-treated rats were not observed with respect to absolute volume of the seminiferous tubules, interstitial space, Leydig cells, blood vessels boundary layer, lymphatic space, macrophages, tubular lumen or absolute tubular length and absolute tubular surface area, mean Sertoli cell nucleoli number per tubular cross-section, mean seminiferous tubule diameter and the mean height of the seminiferous epithelium. A statistically significant decrease in the absolute volume and volume percent of the lymphatic endothelium was observed in the 175 and 250 ppm NaF-treated groups and in the testicular capsule in the 100 ppm NaF-treated groups. The significance of this finding is unknown at the present time. Overall, the quantitative information obtained suggests that exposure to NaF at the doses used in the present study does not adversely affect testis structure or spermatogenesis in the rat.     

Lesions in the reproductive tract of boars experimentally infected with porcine rubulavirus

"Blue eye" disease of pigs in Mexico is caused by porcine rubulavirus and characterized by infertility in sows and boars, nervous signs in young pigs, and corneal opacity in pigs of all ages. The pathogenesis of reproductive tract lesions in rubulavirus-infected boars has not previously been investigated. In a first experiment, four 9-month-old boars were inoculated with porcine rubulavirus and killed 5, 15, 30 or 45 days post-inoculation (pi). In a second experiment, four similar boars were inoculated with the same virus and two animals were killed on each of days 70 and 80 pi. Swelling of the head of the epididymis developed in all inoculated boars at approximately day 15 pi. Reduced spermatozoan motility and concentration were detected in semen samples collected from one boar from day 21 pi. At post-mortem examination, nodules were seen in the head of the epididymis of the boars killed 15, 30 or 45 days pi and the right testis of the pig killed 30 days pi was atrophic. Corresponding histopathological epididymal alterations included formation of spermatic granulomas and vacuolar degeneration of ductular epithelium. These lesions were associated with mononuclear cell infiltration and interstitial fibroplasia. Degeneration of seminiferous tubules and interstitial mononuclear cell infiltration were seen in the atrophic testis of the pig killed 30 days pi. There was fibrosis of the head of the epididymis in all boars killed 70 or 80 days pi and one of these animals also had right testicular atrophy associated with degeneration of seminiferous tubules, lymphocytic infiltration and giant cell formation. Porcine rubulavirus antigen was detected by immunofluorescence labelling in the head of the epididymis of the pigs killed 15, 30 or 45 days pi and in one animal killed on day 70 pi. These results indicate that porcine rubulavirus can cause severe epididymo-orchitis and reduced semen quality in sexually mature boars.     

Prevention of seminiferous tubular atrophy in a naturally cryptorchid rat model by early surgical intervention

In an attempt to determine whether the seminiferous tubular atrophy of the cryptorchid testis is preventable by early surgical correction of the cryptorchid state, aberrantly developed gubernacula destined to result in a cryptorchid testis in the Long-Evans cryptorchid (LE/ORL) rat were surgically reimplanted to the bottom of the scrotum on day 10 to 12 of age. Testis descent was monitored and the changes in testicular histology and in the volumes of the seminiferous tubules and Leydig cells were examined at day 60. As expected, normal testis descent occurred on or about day 25. Compared to untreated undescended testes at day 60, relative seminiferous tubular volumes (volume: % +/- SEM) were significantly increased by early surgical reimplantation of the gubemacula (89 +/- 1 vs. 66 +/- 3; P < 0.01). Absolute seminiferous tubular volumes (microliter +/- SEM) were also significantly increased by early surgical intervention when compared to undescended nontreated testes (893 +/- 27 vs. 170 +/- 12; P < 0.01). The testes of the surgically corrected cryptorchid animals were similar in all respects to those found in the descended testes of the sham-operated controls. Relative Leydig cell volume (% +/- SEM) was increased in the untreated cryptorchid testes compared to the surgically corrected testes (5.2 +/- 0.6 vs. 1.2 +/- 1.0; P < 0.05). Relative Leydig cell volumes in the surgically corrected testes were not significantly different from those found in the sham-operated descended controls. A modest but significant (P < 0.05) increase in absolute Leydig cell volume was also noted in the cryptorchid testes when compared both to normal controls or surgically corrected cryptorchid testes. From these observations, we conclude that early gubernaculopexy reverses the histologic changes normally seen in the cryptorchid rat testis to a relatively normal histologic architecture. These data provide experimental evidence to support the value of orchiopexy in the treatment of cryptorchidism.     

Reinitiation of spermatogonial mitotic differentiation in inactive old BDF1 mouse seminiferous tubules transplanted to W/Wv mouse testis

The seminiferous epithelia of old mice (33 mo of age) are composed of spermatogonia and Sertoli cells. Histochemical examination using the anti-c-kit monoclonal antibody demonstrated that the number of differentiating type A spermatogonia decreases with age. To elucidate the differential activity of old mouse spermatogonia, we transplanted extremely thin seminiferous epithelia of old BDF, mice into W/Wv mouse testes and examined whether or not they could reinitiate differentiation. Artificially cryptorchid mice were used as the control. At 2 wk after transplantation, spermatocytes and round spermatids were detected in transplanted seminiferous tubules of the control, whereas the most advanced spermatogenic cells in those of old mice were spermatocytes. At 4 wk after transplantation, although elongated spermatids were detected in transplanted tubules of the control, haploid cells (spermatids) were still undetectable in those derived from old mice. Thus, meiosis was never restored, although spermatogonia of old mice can reinitiate differentiation into spermatocytes under suitable testicular conditions. Since it has been reported in several mammalian species that age-related changes in the testicular microenvironment lead to the gerontal cessation of spermatogenesis, the present results suggest that both a defective extratubular environment and a defective intratubular environment may cause the cessation of spermatogenesis in old BDF, mice.     

Studies on a long-term use of rapeseed products in diets for boars. Pathomorphological changes in the reproductive system, liver and thyroid gland

Three feeding groups were used: the control (SOY) was fed diets without rapeseed products, and the two experimental groups were fed with either 10% rapeseed meal (RSM) or with 12% OO rape seeds (PFRS). Half of the boars from each group were slaughtered after 1 or 2 years. In RSM and PFRS boars steroid-3-beta-ol-dehydrogenase activity was high, whilst Leydig cells were not numerous after 1 year. Degeneration and necrosis of seminiferous epithelium resulting in atrophy of seminiferous tubules appeared in RSM boars after 2 years. In the PFRS group the lesions were stronger and proliferation of Leydig cells with high steroid-3-beta-ol-dehydrogenase activity was observed. In 1-year-old RSM and PFRS boars there were foci of necrosis in the epididymal epithelium. Thyroid weight in RSM boars and liver weight in PFRS boars were distinctly higher only during the first year. In these thyroid glands flattening of glandular epithelium and enlargement of colloid masses were observed, while in the livers, parenchymatic degeneration and structural transformation appeared. Testis weight increased after 2 years in RSM and PFRS boars; however, this had little effect on semen production.     

High scrotal orchidopexy for palpable maldescended testes

OBJECTIVE: To confirm that most spermatic cords of palpable maldescended testes are long enough to place the testes in the scrotum and therefore that a satisfactory scrotal testicular position can be achieved by a single high scrotal incision with less dissection of the inguinal region. PATIENTS AND METHOD: Between January 1991 and June 1995, 106 high scrotal orchidopexies (HSOs) for clinically palpable maldescended testes were carried out in 96 patients (mean age 41 months, range 14 months to 11 years). Ten patients had bilateral undescended testes. Regardless of the initial testicular position or the age of the patients, all orchidopexies were commenced with a high scrotal incision. Ninety-two testes (87%) were placed satisfactorily in the scrotum and the remaining 14 testes (13%) required a second inguinal incision. RESULTS: During the follow-up (mean 16 months, range 8 months to 3 years), 85 testes (80%) showed good anatomical and cosmetic results. Five testes required a repeat conventional orchidopexy 6 months after the HSO. Three testes were excised because they showed atrophic changes; 11 of the 14 testes which required two incisions initially have shown good results. CONCLUSION: High scrotal orchidopexy is a satisfactory approach to any palpable maldescended testis, having the advantage of using a single incision and requiring less dissection and anatomical disruption of the inguinal region, with excellent cosmesis.     

Complementation tagging of cooperating oncogenes in knockout mice

In the testis, 'hyalinization' of the lamina propria of seminiferous tubules is often accompanied by similar changes within the walls of testicular blood vessels. The aim of our study was to investigate the structure of small blood vessels in hyalinized human testes by means of immunohistochemistry, electron microscopy and image analysis methods. Results of immunohistochemical analysis indicated that, despite hyalinization, testicular small blood vessels retained positive immunostaining for desmin and actin. Their basement membranes remained immunopositive for collagen IV and laminin. No proliferative (Ki-67) activity was observed in the blood vessel walls in testes from both control and infertile men. P-170 glycoprotein was found to be expressed only in primary spermatocytes. No difference in expression and localization of this antigen was observed between control and affected testes. Electron microscopy revealed a number of testicular arterioles with a notably narrow lumen due to enlarged endothelial cells in infertile men. Such arterioles also had a thickened subendothelial layer and an abundant tunica adventitia rich in connective tissue fibres and ground substance. Some venules in hyalinized testes displayed increased connective fibres and ground substance in the subendothelial layer, between the smooth muscle cells of the tunica media and the tunica adventitia. However, no changes were found in the capillary network, when compared to controls. Image analysis data showed a statistically significant increase in the surface of tunica intima and adventitia of arterioles and tunica media of venules. It is concluded that hyalinization mostly affects testicular arterioles and venules, but not capillaries. Our immunohistochemical data indicate that the 'nature' and/or extent of hyalinization in testicular small blood vessels differs from that described previously for the lamina propria of seminiferous tubules.     

Testicular calcifications: incidence, histology and proposed pathological criteria for testicular microlithiasis

PURPOSE: Testicular microlithiasis is a clinical syndrome in which men present with innumerable testicular calcifications. Indirect evidence suggests that this syndrome may be associated with an increased risk of germ cell neoplasia. The incidence and types of testicular calcification in normal and diseased testes is unknown. MATERIALS AND METHODS: A series of 131 orchiectomy specimens were reviewed, including 79 germ cell tumors, and 100 entirely embedded autopsy testes in men with no known testicular pathology. RESULTS: Two types of calcifications were identified. Hematoxylin bodies, consisting of amorphous calcific debris, were present in 6 cases associated with germ cell tumors. In contrast, laminated calcifications were found not only in association with germ cell tumors (35 cases), but also in 2 of 4 cryptorchid testes and 6 of the remaining 145 testes (4%). Of these calcifications 61% were multiple. When laminated calcifications were associated with germ cell tumors there was an increased incidence of extension beyond the tunica albuginea (43 versus 21%) and lymphatic invasion (52 versus 17%, p = 0.046 and 0.012, respectively). CONCLUSIONS: Testicular calcifications are heterogeneous. Hematoxylin bodies are specific for germ cell tumors but laminated calcifications, while more common in germ cell tumors, also occur in otherwise normal testes. The pathological criteria for testicular microlithiasis should include the identification of multiple laminated calcifications within seminiferous tubules.     

A randomized, controlled trial of intravenous clodronate in patients with metastatic bone disease and pain

The present study analyses cell loss and proliferation which account for the decrease in the number of germ cell populations in the senile male Octodon degus. This is a good model to study ageing in wild animals, since it has recently been incorporated as a laboratory animal but still has a high degree of genetic heterogeneity, thus representing a situation found in natural systems. The cell loss from pachytene spermatocytes to round spermatids is estimated by cell counts in the cross section of seminiferous tubules. DNA testicular synthesis is measured by scintillation counting and the index of labelling of spermatogonia by radioautography of testes comparing sexually mature young animals and senile animals. Other determinations in both groups are testis weight, thickness of the albuginea and tubular wall, daily sperm production, percentage of depleted seminiferous tubules and nuclear cell diameters of germ cells. The results suggest a decrease in the number of cell population in the senile animals resulting from an increase in physiological cell loss coupled with a decreased proliferative spermatogonial activity. There is also a decreased yield of meiosis in terms of round spermatid production. Lowered testosterone levels both in plasma and testicular parenchymal fluid are found in senile animals. All these senescent changes reflect an altered remodelling activity of the seminiferous epithelium and presumably also of Leydig cells.     

Effects of 6-N-propyl-2-thiouracil on growth, hormonal profiles, carcass and reproductive traits of boars

Neonatal 6-N-propyl-2-thiouracil (PTU)-induced hypothyroidism reduces body weight but increases testicular size in adult male rodents. The objective of this study was to determine the effect of prepubertal PTU treatment on boars. For Experiment I, boars (n = 28) were randomly allotted to eight pens. Each pen received one of four PTU doses (0, 0.01, 0.03 and 0.1% in a basal diet) between 28 and 56 days of age (DOA). Due to a lack of difference among three PTU treatments, PTU-treated boars were pooled. Boars treated with PTU had lower (P < 0.05) ADG during treatment, lighter (P < 0.05) BW after 56 DOA and less (P < 0.05) developed epididymides at 154 DOA. For Experiment II, boars (n = 19) were randomly allotted to six pens. Each pen received one of three PTU treatments orally as: control (carrier), PTU-I (0.002% BW of PTU daily between 7 and 70 DOA), or PTU-II (0.002% BW of PTU daily between 28 and 91 DOA). During treatment, PTU-treated boars had lower (P < 0.05) serum T4 levels, rectal temperature, feed intake and ADG. Boars treated with PTU had lower (P < 0.05) BW between 63 and 154 DOA but higher (P < 0.05) gain/feed between 105 and 133 DOA. Boars treated with PTU had less (P < 0.05) developed epididymides and sperm count per gram testis at 238 DOA. These results suggest that prepubertal PTU-induced hypothyroidism had significant effects on growth, hormonal profiles, and reproductive traits of boars; however, it does not appear to be an effective method for increasing testis size and sperm production of commercial boars.     

A study of the fluctuating factors in the seminiferous epithelial cycle in mice with special attention to statistical studies on diurnal fluctuations and on variations due to testes and testis loci in the relative frequencies of the stages

The influence of the testis and loci within testes on diurnal variations and fluctuations in the seminiferous epithelial cycle was investigated in 30 50-60 day old mice. Histological examination of the seminiferous tubules revealed a typical cellular arrangement for each stage of spermatogenesis in virtually all of the specimens. No apparent diurnal fluctuations were observed in the relative frequency of the various stages between specimens obtained at 6 different times of sacrifice or among the uniform periods over a 24-hour period. However, a significant (p less than .05) difference in the frequencies of the stages was observed between testes among individuals and loci within testes.     

Macrophage migration inhibitory factor production by Leydig cells: evidence for a role in the regulation of testicular function

Macrophage migration inhibitory factor (MIF), described originally as a product of activated T lymphocytes, recently has been found to be released by monocytes/macrophages and the anterior pituitary gland. Immunohistochemical studies of the adult rat testis using an affinity-purified polyclonal antimurine MIF antibody demonstrated strong staining for MIF in Leydig cells and their putative precursors. Peritubular myoid cells and the seminiferous epithelium were negative for MIF staining; however, a weak reaction around the heads of elongated spermatids also was observed. The expression of MIF messenger RNA and protein in whole rat testis was demonstrated by Northern blot and Western blot analyses, respectively. Both MIF messenger RNA and protein immunoreactivity in Leydig cells was observed in testes obtained from long term hypophysectomized rats. Significant concentrations of intracellular MIF were detected in lysates of the TM3 Leydig cell line (7.23 +/- 2.6 pg/microgram protein), and testicular interstitial fluid contained 14.7 +/- 1.6 ng/ml MIF protein, as measured by MIF-specific enzyme-linked immunosorbent assay. To gain insight into the possible biological role of MIF in the testis, cultures of adult rat seminiferous tubules and purified Leydig cells were incubated together with recombinant murine MIF (rMIF). Neither rMIF (50 ng/ml) nor a neutralizing anti-MIF antiserum was found to affect basal or LH-stimulated Leydig cell steroidogenesis in vitro. However, a dose-dependent decrease in the secretion of inhibin by the seminiferous tubules was observed at rMIF concentrations ranging from 10-100 ng/ml. Taken together, these data indicate that Leydig cells produce MIF in vivo and suggest an important regulatory role for this newly discovered mediator of testicular function.     

Xenogeneic spermatogenesis following transplantation of hamster germ cells to mouse testes

It was recently demonstrated that rat spermatogenesis can occur in the seminiferous tubules of an immunodeficient recipient mouse after transplantation of testis cells from a donor rat. In the present study, hamster donor testis cells were transplanted to mice to determine whether xenogeneic spermatogenesis would result. The hamster diverged at least 16 million years ago from the mouse and produces spermatozoa that are larger than, and have a shape distinctly different from, those of the mouse. In four separate experiments with a total of 13 recipient mice, hamster spermatogenesis was identified in the testes of each mouse. Approximately 6% of the tubules examined demonstrated xenogeneic spermatogenesis. In addition, cryopreserved hamster testis cells generated spermatogenesis in recipients. However, abnormalities were noted in hamster spermatids and acrosomes in seminiferous tubules of recipient mice. Hamster spermatozoa were also found in the epididymis of recipient animals, but these spermatozoa generally lacked acrosomes, and heads and tails were separated. Thus, defects in spermiogenesis occur in hamster spermatogenesis in the mouse, which may reflect a limited ability of endogenous mouse Sertoli cells to support fully the larger and evolutionarily distant hamster germ cell. The generation of spermatogenesis from frozen hamster cells now adds this species to the mouse and rat, in which spermatogonial stem cells also can be cryopreserved. This finding has immediate application to valuable animals of many species, because the cells could be stored until suitable recipients are identified or culture techniques devised to expand the stem cell population.     

Congenital undescended testes in neonatal pigs and the effect of exogenous calcitonin gene-related peptide

PURPOSE: We investigated the neonatal piglet as a possible animal model for cryptorchidism and to determine whether calcitonin gene-related peptide (CGRP), which has been proposed to regulate inguinoscrotal testicular descent, could induce testicular descent in piglets with congenital cryptorchidism. MATERIALS AND METHODS: We examined 38 cryptorchid piglets to document the anatomy in 8 and to investigate the role of CGRP in 30. The 2-week-old piglets were allocated randomly to receive a mini-osmotic pump containing CGRP at various concentrations or phosphate buffered saline. The pump was inserted surgically into the ipsilateral scrotum, with the contents blinded to the surgeon. The positions of the testes, pump and anatomical landmarks were measured and photographed. The pigs were sacrificed and dissected 2 weeks later, and the positions were remeasured and photographed. The testes were examined histologically. RESULTS: The 3 variants of cryptorchidism observed were intra-abdominal in 20 cases, inguinal in 9 and lateral inguinal ectopic in 9. CGRP had no effect on intra-abdominal or ectopic testes. In contrast, for inguinal testes exogenous CGRP caused a slight but significant 10 +/- 7.9 mm. descent towards the pump in 5 cases compared to -2.9 +/- 5.8 mm. in 4 controls. CONCLUSIONS: Exogenous CGRP stimulated migration of inguinal testes that had been arrested in the line of descent while ectopic testes did not respond. These results support a role for CGRP in testicular descent and suggest that a slow release depot preparation might be useful as a possible treatment in some forms of cryptorchidism.     

Heterotopic transplantation as a model to study the regulation of spermatogenesis; some histomorphological considerations about sperm decline in man

A novel animal model (syngeneic neonatal testicular graft transplanted under the skin of the outer ear in adult inbred Fischer rats that had been castrated, hypophysectomised, and/or subjected to hormonal replacement therapy) was developed to study regulation of spermatogenesis and Sertoli cell number. Given that Sertoli cell number and testicular size are important in determining spermatozoan production rates, this model was first used to study Sertoli cell proliferation, testicular size, and establishment of germ cells. The specific objectives were to determine the developmental pattern of Sertoli cell numbers in transplanted testes and the effect of number of testes transplanted, sex of hosts, pituitary hormonal removal, and replacement on Sertoli cell number, hormonal status of the host, and establishment of germ cells. A few tubules had complete spermatogenesis at 90 days posttransplantation, indicating that Sertoli cells in some of these tubules were functional. Leydig cell structure appeared to be normal, but the density of these interstitial cells was greater than that in testes of intact rats. Although the weight of the seminal vesicles and prostate were maintained in the castrated host with transplants, both serum FSH and LH concentrations were higher than intact control rats. Leukocytic infiltration of testes was not observed in intact rats or in rats receiving neonatal testes. Although transplanted testes showed a delay in reaching the plateau value for Sertoli cell number per testis and although the value reached was lower than in intact testes, the developmental pattern of Sertoli cell proliferation (early division of cells followed by stabilized number of cells) in transplanted testes was similar to that in intact rats. Hypophysectomy reduced the growth of testicular grafts, and hormonal replacement via retransplantation to pituitary intact hosts enhances Sertoli cell proliferation and testicular growth. When two on four testes were transplanted into castrated males or ovariectomized female hosts for 65 days, there was no difference in the graft weights or Sertoli cell numbers between sexes of hosts. Four transplanted testes per rat produced more total testicular parenchyma and a greater number of Sertoli cells per testis than did two testes regardless of sex of the host. Transplantation of six or eight testes produced more total Sertoli cells/host than that found in testes of intact rats. Using hormonal therapy in hypophysectomized hosts, the testicular parenchymal weight was greater for pituitary-intact hosts and FSH-LH combination than the control media. There was no statistically significant difference among the media control, LH, FSH, and GH. This testicular transplant model has shown that the period of Sertoli cell proliferation can be delayed by hypophysectomy, that Sertoli cell number can be influenced by endogenous and exogenous hormones, and that a major component in regulation of testicular size is at the level of the testis. Hence, this model should facilitate study of experimental endocrine manipulation control and potential experimental intervention to increase Sertoli cell number, testicular size, and spermatogenesis. Regarding human sperm count decline in recent years, there appears to be no significant decline in Sertoli cell number or spermatogenic potential in a group of North American men. However, there was a significant decline in volume/man of Leydig cells and volume/man of Leydig cell cytoplasm.     

LDL subclass phenotypes and the insulin resistance syndrome in women

An experiment was conducted to examine the appearance of the seminiferous tubule 20 days after a single exposure of the testes of rams to a scrotal temperature of about 42 degrees C for 45 min. Ten of the animals were surgically hypophysectomized and five were simultaneously heated; these rams were treated twice a day with ovine pituitary extract to avoid modifications in the negative feedback from the testes to the pituitary and consequent changes in gonadotrophin secretion. Six intact rams (three heated and three unheated) were also studied. The pituitary extract significantly increased the testis weight and spermatogonial multiplications from A1 spermatogonia onwards. Twenty days after the heat treatment, testis weight was significantly reduced by heating; both tubular and intertubular tissues were affected. The total length of seminiferous tubules per testis was not modified, whereas the mean seminiferous tubule diameter was significantly reduced after heating. The total number of Sertoli cells per testis was not significantly modified, while their mean cross-sectional nuclear area was significantly reduced by heat treatment. A decrease in the number of all germ cells except A0 spermatogonia, from A1 spermatogonia onwards, was observed. The number of round spermatids decreased by 95 and 90%, slightly more than the diplotene primary spermatocytes (76 and 77%) and elongated spermatids (79 and 85%) in hypophysectomized pituitary extract-treated and intact rams, respectively. Round and elongated spermatids would be derived from germ cells that were respectively leptotene and young pachytene primary spermatocytes at the time of heating, whereas diplotene primary spermatocytes would have been type B spermatogonia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sexual maturation of boars and growth of swine exposed to extended photoperiod during decreasing natural photoperiod

Littermate pairs of crossbred boars, barrows and gilts were used to study the effects of an artificially extended photoperiod during decreasing daylength on puberty in boars and on weight gain and feed efficiency. Libido scores of the boars exposed to the extended photoperiod were higher (P < .01) than those of controls at 24 and 26 weeks of age. At 26 weeks of age, semen had been collected from 74% of the boars on supplemental light but from only 26% of the controls. Lighting treatment did not affect semen quality. The number of ejaculates previously collected did affect semen quality. Motility and total sperm per ejaculate increased with increasing ejaculate number, while the percentage of abnormalities appeared to decrease. A second group of boars was delayed in the development of mating behavior, perhaps because of inadvertent consumption of Gibberella zeae-infected corn. The extended photoperiod did not exert a beneficial effect on weight gain or feed efficiency of boars, barrows or gilts.     

Susceptibility of alpine ibex to conjunctivitis caused by inoculation of a sheep-strain of Mycoplasma conjunctivae

The genetic expression of insulin-like growth factor II (IGF-II) mRNA was studied in healthy adult testes and in hypoplastic testes of polled Murciano-Granadina goats by means of in situ hybridization. A positive reaction in spermatogonia, pachytene spermatocytes and a few peritubular myoid cells was observed using the ovine antisense oligonucleotide in healthy testes. The hypoplastic testes displayed a loss of germinal epithelium and a slight thickening of the basement membranes. A limited number of immature germinal cells displayed a lesser hybridization reaction, while the expression of IGF-II mRNA observed in the peritubular myoid cells was similar to that seen in healthy testes. In hypoplastic testes, IGF-II mRNA expression within germinal cells decreased with increasing hypoplasia within the seminiferous epithelium and there was no hybridization within the tubules in cases of severely disrupted spermatogenesis. These results suggest that testicular hypoplasia is associated with changes in the expression of IGF-II mRNA.