Effects of growth hormone, prolactin, insulin-like growth factors, and gonadotropins on progesterone secretion by porcine luteal cells

Growth hormone (GH) and IGF-I have receptors within the corpus luteum (CL) and stimulate CL function. Our objective was to investigate the effects of GH, prolactin (PRL), IGF-I, IGF-II, LH, and FSH on progesterone secretion by porcine luteal cells during mid-pregnancy. Gilts (crossbred Yorkshire/Landrace) were slaughtered on d 44 of pregnancy and CL were collected. Large and small luteal cells (LLC and SLC, respectively) were obtained from dissociated CL and separated by elutriation. Luteal cells were incubated with 0, 1, 10, or 100 ng/mL of GH, PRL, IGF-I, IGF-II, LH, and FSH or combinations of 10 ng/mL of these reagents for 24 or 48 h. Culture media were harvested and concentrations of progesterone analyzed by radioimmunoassay. Growth hormone, PRL, and IGF-I increased (P < .05; 100 ng/mL dose) concentrations of progesterone in media of LLC. Insulin-like growth factor-II, LH, and FSH had no effect on progesterone in LLC cultures. In SLC cultures, GH, PRL, IGF-I, IGF-II, and FSH failed to stimulate progesterone secretion, whereas LH increased progesterone secretion (linear effect of dose; P < .05). Combinations (10 ng/mL each hormone) of GH and IGF-I or PRL and IGF-I increased progesterone secretion by LLC compared with control, GH, PRL, or IGF-I alone (P < .05). Similar combinations of GH or PRL with IGF-I had no effect on SLC. Conclusions are that GH and PRL are stimulatory to progesterone secretion by LLC (location of GH receptor) and SLC are responsive to LH during mid-pregnancy. Both GH and PRL are synergistic with IGF-I for increased progesterone secretion.     

Role of estradiol-17 beta and progesterone in regulating constriction of ovine uterine arteries

Fistulas between the abdominal aorta and renal vein are exceedingly rare. Diagnostic delays are not unusual. Correction can be extremely difficult because of anatomical distortion and size of the arterialized veins. A young woman with such a fistula following a gunshot wound is presented. Four years following injury, the fistula was repaired successfully during intentional arrest of the circulation for 7 minutes. This was accomplished with deep hypothermia and cardiopulmonary bypass. No serious problems occurred during the operation. The patient tolerated the procedure well and has been relieved of her symptoms completely. Most patients with traumatic or spontaneous arteriovenous fistulas can be managed safely and effectively by conventional operative techniques. In selected situations, the risk of total circulatory arrest and deep hypothermia may be less than the risk of uncontrollable bleeding inherent in conventional techniques. Suggested indications for use of total circulatory arrest in vascular surgery are (1) inability to achieve vascular control by more conventional means, (2) massive distention of regional veins as occurrs in well established fistulas of the trunk, (3) one or more prior corrective attempts with use of conventional techniques, and (4) anticipated anatomical distortion and/or multiple abnormal vascular communications. This technique is a valuable approach to the correction of otherwise inoperable cardiovascular lesions.     

Interleukin-1 beta modulates prostaglandin and progesterone production by primate luteal cells in vitro

Increasing evidence suggests that cytokine products of the immune system may play a regulatory role in corpus luteum regulation in several species. The role of cytokines in primate luteal function, however, remains unclear. In the present study we examined the effects of interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), and interferon-gamma (IFN-gamma) on progesterone and prostaglandin (PGE2, PGF2 alpha) production by primate luteal cells in vitro. Specifically, corpora lutea were removed from normally cycling cynomolgus monkeys (n = 30 corpora lutea) during either the early (Days 3-5 after the estimated LH surge), mid (Days 8-10), or late (Days 12-14) luteal phase of the menstrual cycle. The corpora lutea were dispersed into individual cells using collagenase, DNase, and hyaluronidase. Approximately 50,000 viable luteal cells per tube were incubated in Ham's F-10 medium with increasing concentrations of IL-1 beta (0.1-10 ng/ml), TNF alpha (1-100 ng/ml), or IFN-gamma (10-1000 U/ml) in the presence and absence of hCG for 8 h at 37 degrees C. TNF alpha and IFN-gamma had no effect on progesterone PGE2, or PGF2 alpha production during any phase of the cycle at the doses tested. In contrast, IL-1 beta significantly stimulated PGF2 alpha production in a dose-dependent manner during the mid and late luteal phases (p < 0.05). Human CG alone had no effect on PGE2 or PGF2 alpha production by dispersed luteal cells in vitro but inhibited IL-1 beta-stimulated PGF2 alpha production. As expected, hCG stimulated progesterone production by primate luteal cells in vitro. Interestingly, IL-1 beta inhibited this hCG stimulation of progesterone production. In summary, these date suggest that IL-1 beta is a potentially important modulator of prostaglandin production by the primate corpus luteum. In view of this, cytokine-mediated changes in prostaglandin production by the primate corpus luteum may participate in the physiological regulation of luteal function.     

The regulation of progesterone and hCG production from placental cells by interleukin-1beta

Recent outbreaks of foodborne illness and studies by expert groups have established the need for fundamental change in the United States meat and poultry inspection programme to reduce the risk of foodborne illness. The Food Safety and Inspection Service (FSIS) of the United States Department of Agriculture (USDA) has embarked on a broad effort to bring about such change, with particular emphasis on the reduction of pathogenic micro-organisms in raw meat and poultry products. The publication on 25 July 1996 of the Final Rule on pathogen reduction and hazard analysis and critical control point (HACCP) systems was a major milestone in the FSIS strategy for change. The Final Rule provides a framework for change and clarifies the respective roles of industry and government in ensuring the safety of meat and poultry products. With the implementation of this Final Rule underway, the FSIS has been exploring ways in which slaughter inspection carried out under an HACCP-based system can be changed so that food safety risks are addressed more adequately and the allocation of inspection resources is improved further. In addition, the FSIS is broadening the focus of food safety activities to extend beyond slaughter and processing plants by working with industry, academia and other government agencies. Such co-operation should lead to the development of measures to improve food safety before animals reach the slaughter plant and after products leave the inspected establishment for distribution to the retail level. For the future, the FSIS believes that quantitative risk assessments will be at the core of food safety activities. Risk assessments provide the most effective means of identifying how specific pathogens and other hazards may be encountered throughout the farm-to-table chain and of measuring the potential impact of various interventions. In addition, these assessments will be used in the development and evaluation of HACCP systems. The FSIS is currently conducting a quantitative risk assessment for eggs, and several surveys and studies are being performed to supply data needed to conduct other risk assessments. The FSIS has established a food safety research agenda which will fill data gaps.     

An aminopeptidase inhibitor, bestatin, enhances progesterone and oestradiol secretion by porcine granulosa cells stimulated with follicle stimulating hormone in vitro

We examined the presence of cell surface aminopeptidase on cultured porcine granulosa cells by employing the aminopeptidase assay using alanine-p-nitroanilide and histochemical staining using L-leucyl-beta-naphthylamide. Porcine granulosa cells obtained from follicles 4-5 mm in diameter were cultured for 7 days. The aminopeptidase assay showed that the porcine granulosa cell culture had aminopeptidase activity and that this activity was inhibited in a dose-dependent manner by bestatin which binds to cell surfaces and inhibits cell surface aminopeptidases. Histochemical staining also indicated that cultured granulosa cells had aminopeptidase activity. Porcine granulosa cells were cultured in the presence or absence of porcine follicle stimulating hormone (FSH, 3.125 nmol/l) and/or bestatin (0.4, 4.0 and 40.0 micrograms/ml) for 7 days, and the production of progesterone and oestradiol was measured. In the presence of porcine FSH, the production of progesterone and oestradiol by granulosa cells was increased significantly by approximately 5- and 2-fold respectively. These increases were enhanced further by bestatin (40.0 micrograms/ml). In the absence of porcine FSH, progesterone production was enhanced by bestatin (40.0 micrograms/ml), whereas no significant effect of bestatin on oestradiol secretion was observed. These findings indicate that the inhibition of membrane-bound aminopeptidase(s) on the cell surfaces affects the steroidogenesis of granulosa cells, and that these aminopeptidase(s) are important regulators of granulosa cell differentiation.     

Regulation of progesterone biosynthesis in the human placenta by estradiol 17 beta and progesterone

The information available concerning the effects of chemotherapy administered during pregnancy is limited and consists of case reports and small series. A registry has been established at the National Cancer Institute, but there are currently only several hundred cases of neonates exposed to chemotherapy registered. All clinicians who care for women receiving chemotherapy during pregnancy should report those experiences to the National Cancer Institute to increase the data base. When chemotherapy is used during the embryogenesis period in the first trimester there is an increased rate of spontaneous abortion and major birth defects. The most toxic chemotherapeutic agents administered during pregnancy are methotrexate and aminopterin and should be avoided when possible, particularly during the first trimester. Pregnancy-related physiologic changes should be kept in mind when dosing and administering cytotoxic chemotherapy. The risk of fetal malformation when chemotherapy is administered during the second and third trimesters is probably not greater than background rate, but there may be a greater risk of stillbirth, fetal growth restriction, premature birth, and maternal and fetal myelosuppression. Breastfeeding should be avoided in women receiving chemotherapy.     

Effect of estradiol-17 beta on preprolactin messenger ribonucleic acid activity in the rat pituitary gland

Rat pituitary RNA was translated in the wheat germ system. Preprolactin messenger RNA activity was estimated by adsorption of cell-free products to solid phase antiprolactin. When male rats were injected for 4 days with estradiol-17beta, pituitary preprolactin mRNA activity was increased 2.5- to 3.0-fold over controls. This increase was evident when either total RNA, poly(adenylic acid) RNA, or polysomal RNA was translated in the cell-free system. In male rats receiving daily injections of estradiol-17beta, preprolactin mRNA activity was increased to an apparent maximum of 300% of controls after 7 days of treatment. Our data also indicate that estradiol increases preprolactin mRNA activity per microgram of RNA as well as the pituitary content of RNA. After estradiol treatment was discontinued, preprolactin mRNA activity declined to 50% of the maximum stimulation after approximately 2 days. In ovariectomized retired breeder female rats, a 5-fold increase in preprolactin activity over ovariectomized controls was obtained. In other studies, a 2-fold increase in preprolactin mRNA activity was obtained in male rats 24 h after a single injection of pimozide, a dopamine blocking drug.     

Effect of synthetic progestins on the uptake of labelled testosterone and estradiol-17beta by the accessory genital organs of male rats

The effect of pretreatment with norethindrone (NE) or 17-hydroxyprogesterone caproate (17-OHPC) on the uptake of tritiated testosterone and estradiol-17beta by the accessory sex organs of castrated and intact rats was investigated. A selective in vivo increase in the incorporation of tritiated testosterone and estradiol-17beta was observed at 48 hours after castration. The uptake of testosterone was greatest in the epididymis, while the maximum incorporation of estradiol-17beta was by the vas deferens. Pretreatment with NE or 17-OHPC decreased the incorporation of testosterone by all the accessory organs of castrated rats. NE decreased the incorporation of tritiated estradiol-17beta in the epididymis and seminal vesicles only, while 17-OHPC decreased the uptake in all accessory organs.     

Differential control of immunoreactive alpha-inhibin and progesterone production by marmoset luteal cells in vitro: evidence for a paracrine action of alpha-inhibin on basal and gonadotropin-stimulated progesterone production

There is an increase in plasma concentrations of immunoreactive (ir) inhibin unaccompanied by a rise in plasma progesterone during early pregnancy in the marmoset monkey. We investigated the potential involvement of hCG and prostaglandin E2 (PGE2) in stimulating a selective increase in inhibin concentrations by measuring the production of ir-alpha-inhibin and progesterone by dispersed luteal cells cultured under serum-free conditions. After one day, hCG had no effect on progesterone production by the cells but stimulated a significant increase (p < 0.05) in alpha-inhibin production. PGE2 significantly increased progesterone production (p < 0.001) but inhibited the production of alpha-inhibin (p < 0.001). After three days of culture, output of alpha-inhibin fell to low levels and no significant effect of hCG or PGE2 was detected. Progesterone also fell with time in culture, but hCG maintained production resulting in a significant increase above control levels (p < 0.001). The addition of low density lipoproteins (LDL) to the culture medium increased progesterone production (p < 0.001) while decreasing alpha-inhibin production (p < 0.01). Immunoneutralization of endogenous alpha-inhibin resulted in a significant decrease in both basal (p < 0.05) and gonadotropin-stimulated (p < 0.05) progesterone concentrations. These results provide further evidence for differential control of progesterone and alpha-inhibin production by marmoset luteal cells and show that hCG can selectively stimulate alpha-inhibin production. In addition, alpha-inhibin may have a local paracrine action in the marmoset CL, enhancing both basal and gonadotropin-stimulated progesterone secretion.     

Invasion of cytotrophoblastic JEG-3 cells is stimulated by hCG in vitro

Trophoblast invasion into the uterine wall is controlled by many factors. Previously, a human chorionic gonadotropin (hCG) receptor has been found to be expressed on invasive trophoblast as well as on choriocarcinoma cells implying a possible role for the hormone in trophoblast invasion. Therefore, this study examined the role of hCG in the invasion of trophoblastic (JEG-3) cells. Increasing hCG concentrations were applied in a trophoblast invasion model, JEG-3, through matrigel-coated filters. The proliferation was quantified by WST-1 cleavage assay. Cell migration was studied by examining the number of cells that had passed the uncoated porous (8-microm pore size) filters. After staining, filters were examined microscopically for cells on the underside of the membrane. A quantitative protease assay was also performed. Flow cytometric analysis of alpha5 and alpha6 integrin subunits, which are essential for interactions between cells and extracellular matrix, was performed. hCG increased significantly (P<0.01) the in vitro invasion of trophoblastic JEG-3 cells in a dose-dependent manner. Migration was also increased by hCG (P<0.01). However, cell proliferation remained unchanged. The second messenger analogue dibutyryl cAMP (db cAMP) and the cAMP elevating factor (forskolin) mimicked the effects of hCG by stimulating a dose-dependent increase of trophoblastic cell UEG-3) invasion. The collagenolytic activity of trophoblastic cells (EG-3) was increased by hCG stimulation. No changes were shown in the expression of alpha5 and alpha6 integrin subunits on JEG-3 cells. In vitro hCG is a regulatory factor of invasion and migration in trophoblastic JEG-3 cells, whereas proliferation is not influenced. The endogenous production of hCG by the trophoblast in vivo implies an autocrine control of invasion processes by hCG.     

Prostaglandin F and progesterone secretion by porcine endometrium and corpus luteum in vitro

Slices of porcine endometrium and corpus luteum tissue obtained from mature sows throughout the luteal phase of the oestrous cycle were incubated in culture medium which was analysed at regular intervals over a period of 8 hours for prostaglandin F and progesterone. Prostaglandin F secretion was greatest by endometrium obtained during the mid III to late I luteal stage of the cycle and the increased levels secreted by this tissue were paralleled by high levels of secretion from corpus luteum tissue. The addition of indomethacin (10 mug/ml) to the culture medium completely abolished prostaglandin F secretion by both endometrium and luteal tissue indicating that the high levels of the prostaglandin were due to synthesis. Progesterone secretion by the corpus luteum was maximal from early luteal tissue and had declined to considerably lower levels by late stage tissue when prostaglandin secretion was greatest. The possible physiological significance of luteal prostaglandin F secretion is discussed.     

Adenosine triphosphate-dependent transport of estradiol-17beta(beta-D-glucuronide) in membrane vesicles by MDR1 expressed in insect cells

MDR1, an ABC transporter that confers multidrug resistance in tumor cells, is constitutively expressed in normal liver canalicular membrane. Human MDR1-expressing multidrug-resistant cells display increased resistance to estradiol-17beta(beta-D-glucuronide) (E217G). MDR1 substrates/modulators inhibit adenosine triphosphate (ATP)-dependent transport of E217G in the rat canalicular membrane and protect against E217G-mediated cholestasis in isolated perfused rat liver. The present studies were designed to determine if E217G is a substrate for MDR1 using a baculovirus expression system and if other estrogen glucuronides interact with MDR1. ATP-dependent transport of E217G (10 micromol/L) was linear for up to 2 minutes and yielded a rate of 45.6 pmol/min/mg protein in membrane vesicles from Sf9 cells infected with MDR1-baculovirus. This transport was saturable (Km = 62 micromol/L) and occurred into an osmotically sensitive space. ATP-dependent transport of E217G (10 micromol/L) was inhibited 63% by 10 micromol/L daunomycin, but not by 100 micromol/L S-(2,4-dinitrophenyl)glutathione (GS-DNP) (a substrate for canalicular multispecific organic anion transporter [cMOAT]). Glucuronide conjugates of the estrogen D-ring (100 micromol/L), estriol-17beta(beta-D-glucuronide) (E317G) and estriol-16(beta-D-glucuronide) (E316G), inhibited MDR1-mediated E217G transport by 58% and 35%, respectively. In contrast, noncholestatic glucuronides, estradiol-3-(beta-D-glucuronide) (E23G) or estradiol-3-sulfate-17beta(beta-D-glucuronide) (E23SO417G), had no effect. E217G neither stimulated MDR1 ATPase activity nor inhibited verapamil-stimulated ATPase activity. Infusion of 1.5 micromol/L doxorubicin or 1 micromol/L taxol protected against cholestasis induced by E316G and E317G in isolated perfused rat liver. These studies identify E217G, and probably E316G and E317G, as endogenous substrates for MDR1.     

Effect of estradiol-17beta & estriol-3-methyl ether on spermatozoa & genital organs of rats

The effect of estradiol-17beta (E2) and estriol-3-methyl ether on spermatozoa and genital organs was investigated in rats. The motility pattern of spermatozoa in epididymis and vas deferens was adversely affected by both treatments in intact rats. The number of spermatozoa in cauda epididymis was significantly (p less than .05) reduced after treatment with estriol-3-methyl ether, however, the combined treatment had a more severe effect. Sperm transport was accelerated after both treatments in castrated rats. No effect was observed on weight and gross histology of testis. Epididymis weight was reduced only after combined treatment. The weight of seminal vesicles, ventral prostate, and vas deferens was reduced after both treatments. However, in castrated rats there was a transient increase in the weight of vas deferens and seminal vesicles after 7 days of E2 treatment while ventral prostate weight was reduced.     

The tissue distribution of porcine 17 beta-estradiol dehydrogenase and its induction by progesterone

Porcine 17 beta-estradiol dehydrogenase (EDH) was recently purified and cloned. It catalyzes the NAD(+)-dependent oxidation of estradiol to estrone 360-fold more efficiently than the back reaction with NADPH. The 32 kDa EDH is cut from an 80 kDa primary translation product with a multidomain structure unknown for other hydroxysteroid dehydrogenases. The highest EDH activities and strongest immunoreactions are found in liver (hepatocytes) and kidney (proximal tubuli) followed by uterus (luminal and glandular epithelium), lung (bronchial epithelium). Progesterone treatment of ovariectomized gilts stimulates oxidative EDH activity in uterus, anterior pituitary, skeletal muscle (diaphragm) and kidney. Constitutive levels of EDH activity were seen in the adrenals, the lung and the liver.     

Changes in serum triiodothyronine, thyroxine, estradiol-17 beta, progesterone levels and egg production in hypocholesterolemia induced Japanese quails Coturnix coturnix japanica

Mature healthy female Japanese quails injected (i.p.) with gemfibrozil at two dose levels for 1,2,3 and 4 weeks induced hypocholesterolemia as observed by the serum cholesterol concentration which was more severe with the higher dose. Liver and ovarian cholesterol contents decreased in 3rd and 4th week of the treatment. Significant (P > 0.05) increase in serum triiodothyronine (T3) and thyroxine (T4) level were observed between 3rd and 4th week while serum estradiol-17 beta and progesterone levels declined continuously from Ist week till the termination of the treatment. The quantity and quality of the eggs produced by the treated quails were inferior. These results indicate that induction of hypocholesterolemia impaired the reproductive efficiency of quails.     

Effect of 17 beta-estradiol on secretion of platelet-activating factor acetylhydrolase by HepG2 cells

Estrogen has been shown to decrease plasma platelet-activating factor (PAF) acetylhydrolase activity, but the precise mechanisms are not known. We examined the effect of estradiol on the secretion of PAF acetylhydrolase by HepG2 cells. In our previous study, we demonstrated the production of this enzyme by HepG2 cells, which we used as an experimental model of normal hepatocytes. 17 beta-Estradiol mildly but consistently inhibited the secretion of PAF acetylhydrolase by HepG2 cells in a concentration-dependent manner. Under basal conditions, HepG2 cells secreted 42.3 pmol/mg cell protein/min PAF acetylhydrolase in 24 hours (mean of 8 dishes), and the presence of 10(-7) mol/L 17 beta-estradiol decreased the secretion to 77% +/- 10.3% of control values (mean +/- SD, n = 8, P < .02). 17 beta-Estradiol treatment affected neither the secretion of apolipoprotein (apo) A-I nor cell-associated PAF acetylhydrolase activity. Electrophoretic separation of [35S]methionine-labeled PAF acetylhydrolase revealed a single band whose molecular weight was approximately 43,000 d. We conclude that estrogen decreases the secretion of PAF acetylhydrolase by the liver, and it may explain, at least in part, the effect of estrogen on plasma PAF acetylhydrolase.     

Quantification of receptors for estradiol-17 beta and progesterone in the pituitary and hypothalamus of prepubertal gilts induced to ovulate with pregnant mare's serum and human chorionic gonadotropin

Nuclear and cytoplasmic exchange assays were developed and validated to quantify receptors for estradiol-17 beta (E217 beta) and progesterone (P4) in hypothalamic and pituitary tissues of gilts before, during, and after treatment with pregnant mare's serum (PMS) and human chorionic gonadotropin (hCG). Prepubertal gilts, 5 months old, were assigned randomly to four treatments. One group of gilts received 500 IU PMS (Day 0) and were sacrificed 2 days later (2 days post-PMS); another group received 500 IU PMS on Days 0 and 2, and were sacrificed 4 days from the initial injection (4 days post-PMS). A third group of gilts received PMS (500 IU) on Days 0 and 2, 1000 IU hCG on Day 4, and were sacrificed 5 days after hCG (5 days post-hCG). Controls were given saline on Days 0, 2 and 4 and sacrificed on Day 6. In pituitary tissues, there were no significant changes in numbers of cytoplasmic E2 17 beta receptors, cytoplasmic P4 receptors, nuclear P4 receptors or nuclear E2 17 beta receptors among the control, 2 days post-PMS, 4 days post-PMS or 5 days post-hCG treatment groups. In hypothalamic tissues, no differences in cytoplasmic E2 17 beta receptors, cytoplasmic P4 receptors or nuclear P4 receptors were found among any of the treatments. Nuclear receptors for E2 17 beta in hypothalamic tissues were greater, however, in gilts 2 days post-PMS (P less than 0.05) than in controls or 5 days post-hCG gilts, but they were not different from gilts 4 days post-PMS. Follicular development and serum concentrations of E2 17 beta followed the expected patterns after PMS; only ovaries from hCG-treated pigs contained corpora lutea. Because the PMS-hCG regimen simulated the onset of puberty, it seems that gilts attain puberty without a significant change in the number of receptors for E2 17 beta and P4 in the pituitary or hypothalamus.     

Influence of light dark cycles on estradiol-17 beta induced luteinizing hormone patterns of the prepuberal gilt

Two groups of Yorkshire gilts (110 d of age) were maintained in two light regimens. Both light regimens consisted of 14 h of light and 10 h of darkness, but were 180 degrees out of phase. Gilts in Group 1 received light from 1200 to 0200 and gilts in Group 2 from 2400 to 1400. At approximately 140 d of age each group was divided into four subgroups of eight gilts each (1A, 1B, 1C, 1D or 2A, 2B, 2C, 2D). All gilts were blood sampled at 2-h intervals for 5 d commencing on d 142. The four subgroups received a single injection of estradiol (15 micrograms/kg body weight) on d 143 at either 2400 (A), 0600 (B), 1200 (C), or 1800 (D). For pigs in Groups 1A and 1D, the injection of estradiol coincided with the animals' "subjective day" and the injections given to Groups 1B and 1C with their "subjective night." When estradiol-17 beta (E2) was administered to the gilts during their subjective day the LH profile showed one peak, whereas when E2 was administered during dark hours the profile exhibited two peaks (P < .0001). In Group 2 for which the light cycle was reversed, the well-defined spikes of LH were found to coincide with the injections of estradiol administered during the dark hours. Smaller biphasic peaks of LH occurred when injections of estradiol coincided with the light hours.(ABSTRACT TRUNCATED AT 250 WORDS)