The reproductive cycle of the female American alligator (Alligator mississippiensis)

We examined ovarian and oviducal gross morphology and collected blood samples from wild female alligators in central Florida during most of the year. Females with vitellogenic follicles were observed throughout the year, although ovaries containing follicles larger than 15 mm were seen only during the spring and early summer (March-June). We detected a poor relationship between female body size and the number of vitellogenic follicles whereas body size was significantly correlated with clutch size. Plasma samples were analyzed for (1) estradiol-17beta (E2), testosterone (T), and corticosterone by specific radioimmunoassays; (2) vitellogenin by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis; and (3) total protein, phosphorus, and calcium by spectrophotometric assays. Reproductively active females showed elevated plasma concentrations of E2 during the fall (September-November) and spring (March-May) whereas non-reproductively active females exhibited basal levels with no apparent peaks. Vitellogenin was detected in the plasma during the same months that plasma E2 concentrations were elevated. Elevated plasma vitellogenin and E2 were not correlated with plasma total protein but were correlated with plasma calcium concentration. During late vitellogenesis, plasma T concentrations were elevated in reproductively active females coincident with a period of intense courtship and mating. Corticosterone plasma concentrations exhibit no significant monthly variation, nor apparent changes during various stages of reproductive activity although plasma concentrations were elevated during late gravidity. Our data suggest that female reproductive activity begins in the fall with an increase in plasma E2 concentration in September or October and vitellogenesis in October. Ovarian activity slows during winter and reactivates with the onset of spring.     

The value of a fabric-coated self-expanding stent in iliac arterial occlusions or aneurysms--the primary and long-term results

The present study focused on the role of catecholaminergic neurons and estrogens on the release of gonadotropins I and II in immature and early vitellogenic female rainbow trout. The ovariectomy-induced increase of GtH I blood levels (from about 10 to 15 ng/ml) was prevented in vitellogenic fish by E2 supplementation. E2 implantation of immature fish decreased blood GtH I levels (from about 6 to 1 ng/ml). Blood levels of GtH II were low (about 0.5 ng/ml) and not altered by ovariectomy and E2 treatment. These data demonstrate that estrogens exert a negative feedback on the release of GtH I in trout. A treatment with alpha-methyl-p-tyrosine (MPT), an inhibitor of catecholamine synthesis, increased blood GtH II levels of sham-operated vitellogenic fish and ovariectomized fish implanted with E2, but had no effects in ovariectomized fish. MPT did not modify blood GtH I levels in any experimental group. A treatment of E2-implanted immature or vitellogenic fish with the dopamine antagonist pimozide also increased blood GtH II levels, but did not significantly change blood GtH I levels. These data demonstrate that release of GtH II, but not of GtH I, depends on an E2-activated DA inhibitory tone.     

Gonadal in vitro androstenedione metabolism and changes in some plasma and gonadal steroid hormones during sex inversion of the protandrous sea bass, Lates calcarifer

Steroidogenesis in the gonad of the protandrous sea bass, Lates calcarifer, was examined in vitro in spermiating testis, previtellogenic ovary, and transitional gonads. Gonadal tissues were incubated with tritiated androstenedione. Metabolites were analyzed by thin-layer chromatography, high-performance liquid chromatography, microchemical reactions, and crystallization to constant specific activity. 17 beta-Hydroxysteroid dehydrogenase, 5 beta-reductase, and 3 alpha-hydroxysteroid dehydrogenase activities were found in all of the sex types. On the other hand, 11 beta-hydroxysteroid dehydrogenase and 11 beta-hydroxylase activities were found only when testicular tissue was present, i.e., in testis and early transitional gonad. A low aromatase activity leading to estrone synthesis was detected in the previtellogenic ovary. In late transitional gonads, a major metabolite (metabolite X) was suggestively identified as a 3-ester of 17 beta-estradiol according to its chemical and immunological characteristics. Levels of 17 beta-estradiol (E2), the metabolite X, testosterone (T), and 11-ketotestosterone (11KT) were also measured by radioimmunoassay in plasma, before (January and February) and during (March and April) the sex inversion process. Plasma E2 was virtually undetectable (means below 25 pg/ml), although higher levels of metabolite X were found in transitional fish (485 +/- 432 pg/ml in March). Throughout this period, plasma levels of T and 11KT and the androgens/estrogens ratio were significantly higher in males than in transitional fish, where these levels decreased during the sex inversion period. The level of in vitro synthesis of metabolite X was high in transitional gonads, but their concentrations were very low (0.07 +/- 0.09 ng of equivalent E2/g in transitional gonads against 0.22 +/- 0.37 ng of equivalent E2/g in testes and 2.16 +/- 2.7 ng of equivalent E2/g in ovaries).     

Human plasma leptin in obese subjects and diabetics

Leptin is the protein product of the ob gene, an adipocyte-specific gene, recently discovered in mice. Plasma leptin levels were determined in six normals, twenty-one subjects with impaired glucose tolerance, and forty-nine untreated NIDDM subjects. They increased with the augmentation of obesity (body mass index, BMI kg/m2) and were higher in females than in males: in BMI less than 25 kg/m2 the values of plasma leptin were 2.24 +/- 0.25 ng/ml (n=29) in males and 3.01 +/- 0.39 ng/ml (n=13) in females (P<0.054), respectively, in BMI between 25 kg/m2 and 30 kg/m2 they were 3.14 +/- 0.31 ng/ml (n=10) in males and 10.66 +/- 2.86 ng/ml (n=7) in females (P<0.0018) and in BMI higher than 30 kg/m2 their levels were 8.98 +/- 1.5 ng/ml (n=11) and 11.74 +/- 2.2 ng/ml (n=6) (P<0.23), respectively. The severity of diabetes mellitus judged from the fasting plasma glucose level had no influence on the plasma leptin levels during OGTT, but the leptin levels decreased significantly during a tolerance test (P<0.001), and similar results were also seen during a breakfast test. The fasting plasma leptin in the male with FBS less than 140 mg/dl had a significant correlation with the fasting plasma IRI level, but this correlation disappeared after taking obesity into consideration. Thus the plasma leptin was chiefly dependent on the body weight and gender and had no special relation to diabetic severity.     

Reproductive steroids during maturation in a primitive teleost, the Pacific herring (Clupea harengus pallasi)

Concentrations of reproductive steroids were measured in the plasma of captive Pacific herring, Clupea harengus pallasi, (1) prior to ovulation and milt production, (2) during the periovulatory and newly milt-producing period, (3) during a "ripe" holding period after ovulation and during milt production, and (4) before and after spawning. 17alpha,20beta-Dihydroxyprogesterone (17,20beta-P), despite being present only in low concentrations in the unconjugated (free) form (<10 ng/ml), is likely to be the maturation inducing steroid in females and was associated with the initiation of milt production in males since its levels are elevated coincidentally with these events. Glucuronated 17,20beta-P, free 17alpha-hydroxyprogesterone (17-P), and free and glucuronated 3alpha, 17alpha-dihydroxy-5beta-pregnan-20-one (3alpha,17-P-5beta) were present in high concentrations (140-250 ng/ml) in periovulatory females and newly milt-producing males. This steroid pattern suggests that the low levels of 17,20beta-P are due to glucuronation and competitive conversion of its precursor, 17-P, to free and glucuronated 3alpha, 17-P-5beta. Glucuronated testosterone was the principal steroid in preovulatory and premilt-producing fish (200-350 ng/ml), coincident with similar levels of glucuronated 11-ketotestosterone in males. After ovulation females did not spawn synchronously until 2 months later, which may be partially due to reduced environmental cues in the captive situation, while male fish released milt sporadically throughout the ripe holding period. Steroidal indicators of readiness to spawn in females or males were not detected. Rather, levels of all steroids gradually decreased in ripe holding fish (<30 ng/ml) to reach even lower levels (<1 ng/ml) after spawning. We suggest that "runniness" of gametes is a distinctive characteristic of females that are ready to spawn, but that this may result from relaxation of sphincter muscles rather than being an additional maturational step.     

25-Hydroxycholecalciferol levels in bedouins in the Negev

25-Hydroxycholecalciferol (25-HCC) levels were measured in 31 bedouin females and eight bedouin male tribesmen and compared with the levels in Jewish males and females in Beersheba. In nonpregnant bedouin women the mean 25-HCC level was 25.4 ng/ml +/- 9.78. In pregnant bedouin women the mean was 23.4 ng/ml +/- 8.52. In bedouin males the mean level was 25.7 ng/ml +/- 3.03. In Jewish females, both pregnant and nonpregnant, the levels were higher (32.7 ng/ml +/- 6.02 and 44.3 ng/ml +/- 9.24). Jewish males had levels of 32.8 +/- 6.29 ng/ml. No bedouin had plasma levels below 10 ng/ml, and there was no evidence to suggest deficiency of vitamin D in bedouin males or females.     

Propranolol serum levels during twenty-four hours

Propranolol serum levels during a 24-hr period were determined every 2 hr in 9 hospitalized patients with angina pectoris after oral administration of 40 mg of propranolol 3 times a day. After the first, second, and third tablets the mean maximum serum propranolol concentrations averaged 118 +/- 71 ng/ml, 134 +/- 97 ng/ml, and 118 +/- 94 ng/ml and the mean minimum concentrations averaged 21 +/- 18 ng/ml, 45 +/- 25 ng/ml, and 54 +/- 34 ng/ml (+/-SD), respectively. These data show a very wide inter- and intraindividual variation in serum propranolol levels. No relationship was found between serum level and blood pressure or dose (related to body weight).     

Cell differentiation during early development of Nassarius reticulatus L. (Gastropoda, Prosobranchia). II. Morphological changes of nuclei and nucleoi

Serum LH, FSH and prolactin levels were measured in blood samples which were obtained by decapitation from groups of female, neonatally androgenized female and male Wistar rats at 2-day intervals from birth to maturity. An increase in serum FSH levels was observed between 4 and 24 days of age in both the female and androgenized female groups, while a much later increase, between 28 and 44 days of age, occurred in the males. Serum prolactin contrast, serum LH levels were in general low in all three groups of animals, although very high levels (greater than 7 ng/ml) were recorded in 22 out of 168 females and 8 out of 192 males between 4 and 28 days of age, as well as in adult males; occasional high LH levels were also seen in the androgenized females. The nature of the high serum LH levels was investigated in anaesthetized and unanaesthetized immature females by serial blood sampling using a number of techniques. Unexpectedly, only three out of 58 animals had high LH levels: two of these showed an episodic form of LH release during which levels increased to peak values and then declined within a period of about 30 min. On investigation it was found that general disturbance within the 45 min before decapitation could inhibit high LH levels in females aged between 23 and 30 days.     

Analysis of isoxazolyl penicillins and their metabolites in body fluids by high-performance liquid chromatography

A high-performance liquid chromatographic assay method to quantitate the isoxazolyl penicillins, their active metabolites, and their penicilloic acids in serum or urine is described. Separation and analysis is performed using reversed-phase chromatography. Urine samples, after the appropriate dilution, can be assayed directly. Serum samples (0.1 ml) are either extracted with methylene chloride or treated with perchloric acid--methanol. Serum levels as low as 0.4 microgram/ml (extraction procedure) can be assayed accurately.     

Utility of serum progesterone and prolactin analysis for assessing reproductive status in the Asian elephant (Elephas maximus)

Concentrations of serum progesterone and prolactin were assessed during the perioestrous period and throughout gestation in the Asian elephant (Elephas maximus) as a means of generating information of potential use to managers. In > 95% of perioestrous periods (n=35), behavioural oestrus (as determined by bull interest, mounting and/or breeding) coincided with the onset of increased serum progesterone concentrations at the beginning of the luteal phase and continued through Day 7 (Day 1 = first significant serum progesterone rise). Within individuals, 1- to 2-day transient decreases (P < 0.05) in serum progesterone occurred between Days 2 and 9. Notably, no sexual behaviour was observed in any female after this transient fall in progesterone. Prolactin concentrations fluctuated randomly throughout the perioestrous period, with no clear pattern. During the study, four females conceived (one conceived twice), and two delivered three viable offspring. Serum progesterone was elevated above baseline throughout gestation, and then declined precipitously 2-3 days before parturition. Serum prolactin concentrations were significantly elevated above baseline (P < 0.05) after 5-6 months of gestation and remained high until after parturition. This study confirms that serum progesterone and prolactin analyses are useful tools for monitoring the reproductive status of Asian elephant females. Specifically, the transition from low to high progesterone secretion during the late interluteal/early luteal phase is predictive of oestrus and can be used to coordinate breeding efforts. Pregnancy can be confirmed by elevated serum prolactin after 6 months postbreeding, whereas the late gestational decrease in progesterone is predictive of impending parturition.     

Dopamine infusion does not alter LH levels before or after chronic cocaine exposure in female rhesus monkeys

Cocaine stimulates release of luteinizing hormone (LH) in preclinical and clinical studies but the contribution of the indirect dopamine agonist actions of cocaine to its effects on LH are unclear. In the present study, we examined the effects of exogenous dopamine infusions on LH release in drug-naive, normally cycling, female rhesus monkeys. All studies were conducted during the mid-follicular phase (cycle days 6-8). Three successive 80-min dopamine infusions (10 micrograms/kg/min, intravenous) were alternated with 20- or 40-min interruptions of dopamine infusions. There were no significant changes in LH during or following dopamine infusions. Predopamine baseline LH levels averaged 30 +/- 5.4 ng/ml. LH averaged 31.7 +/- 1.3 ng/ml during dopamine infusions and 31.4 +/- 1.3 ng/ml after dopamine infusions stopped. To determine whether chronic cocaine exposure influenced the effect of dopamine on LH, rhesus females were studied after more than 2 years of cocaine self-administration at an average dose of 6.5 +/- 0.2 mg/kg/day. LH averaged 27.3 +/- 3.3 ng/ml during baseline and 26.9 +/- 0.7 ng/ml and 26.1 +/- 0.7 ng/ml during dopamine infusions and interruptions, respectively. Similarly, during withdrawal from cocaine, baseline LH levels averaged 32.1 +/- 4.5 ng/ml, and LH did not change significantly during dopamine infusions (31.2 +/- 1.1 ng/ml) and infusion interruptions (32.1 +/- 1.1 ng/ml). Under the conditions of the present study, dopamine administration did not change LH levels in gonadally intact rhesus monkeys, and these findings are consistent with previous studies in ovariectomized rhesus females. However, these data are not consistent with clinical reports, and some possible implications of this species difference are discussed. Moreover, these data suggest that the stimulation of LH by cocaine may not be explained by its indirect dopamine agonist actions.     

慢性粒细胞白血病患者血浆伊马替尼浓度检测与临床疗效分析

目的 探讨慢性粒细胞白血病(CML)患者服用伊马替尼治疗后,伊马替尼血浆浓度在个体间的差异以及与临床疗效的关系.方法 2005年7月至2008年2月开始服用伊马替尼治疗的CML患者共51例纳入研究,其中男34例,女17例,服用剂量300 mg/d 9例、400 mg/d 37例,600 mg/d5例;采用高效液相色谱法(HPLC)测定患者空腹伊马替尼血浆谷浓度;SPSS13.0软件进行统计分析.结果 伊马替尼血浆谷浓度与服用剂量有关,且个体之间差异较大,为(342～4688)ng/ml;300mg/d剂量组的伊马替尼血浆谷浓度为(1037±514)ng/ml,低于400mg/d剂量组的(2123±1016)ng/ml(t=2.34,P=0.032);300 mg/d剂量组的治疗有效率为66.67%(6/9),低于400 mg/d剂量组的89.19%(33/37)(χ2=7.14,P=0.008);在300、400mg/d剂量组中,39例治疗有效,伊马替尼血浆谷浓度高于治疗效果不理想患者,差异有统计学意义(t=2.25,P=0.037);受试者工作特征曲线(ROC曲线)结果提示伊马替尼血浆谷浓度低于1050 ng/ml者,其临床疗效可能较差,敏感度为84.6%,特异度为71.1%.结论 CML患者服用伊马替尼治疗后药物血浆浓度与服用剂量有关,不同个体间差异较大,血浆谷浓度低于1050 ng/ml提示其临床疗效可能较差.     

Elimination of the influence of intravesical pressure on the micturitional urethral pressure profile by calculation of urethral cross-sectional area: an experimental study

The influence of 17 beta-estradiol (E2) and prolactin was studied on N-methyl-N-nitrosourea (MNU)-induced mammary carcinomas (MCAs) in rats. MNU was intravenously injected once into seven-week-old female. female F344 rats at a dose of 50 mg/kg body weight. Groups of rats also received either 2.5 mg of E2 or a continuous supply of prolactin and/or growth hormone via transplanted MtT/F84 (mammo-somatotropic pituitary tumor). Rats were observed for up to 36 weeks after MNU administration. Although simultaneous administration of MNU and E2 did not much affect the occurrence of MCAs as compared to administration of MNU alone, rats treated with 2.5 mg of E2 for two weeks before MNU administration had significantly reduced occurrence of MCAs compared to those given MNU alone. In contrast, rats with MNU plus MtT/F84 showed high incidence and shortened latency of MCAs and they also had a high incidence of clitorial gland hyperplasias. Average pituitary weights and serum prolactin levels in E2-treated rats were greatly increased compared to those of MNU-alone rats. Average serum E2 levels were about 100 ng/ml in E2-treated rats and 0.05 ng/ml in rats without E2 treatment. Serum prolactin levels were greatly increased in rats with MtT/F84. The results indicated that pretreatment with E2 before MNU administration was inhibitory while increased prolactin caused by grafting MtT/F84 after MNU injection was promotive for the occurrence of MCAs in female F344 rats.     

Changes in levels of cell adhesion molecules, acute phase proteins, lipids and hemostasis in relation to levels of endogenous estrogens during pregnancy and after ovariectomy

The protective effect of oestrogens is probably caused also by the active inhibition of the inflammatory reaction of the acute phase and release of inflammatory cytokines type IL-1 beta or TNF-alpha by this hormone. We formulated this hypothesis because we recorded a drop of the protein of the acute stage, orosomucoid, in relation to the rising oestrogen level during pregnancy (r = -0.511, p < 0.0001). It ensues also from the finding of a lower level of cytoadhesive molecules of sE-selectins in a group of 66 pregnant women (sE-sel.: 32.95 +/- 12.5 ng/ml) with a higher level of 17-beta estradiol (17-beta E2: 9.34 +/- 7.8 nmol/l), as compared with the sE-selectin level in a group of 14 women after ovariectomy (sE-sel.: 43.97 +/- 8.174 ng/ml, p < 0.016) who lacked oestrogen (17-beta E2 0.14 +/- 0.13 nmol/l) and in a group of pregnant women (n 19) in the first trimester with level of 17-beta E2: 1.89 +/- 0.711 nmol/l where the sE-selectin concentrations at the onset pregnancy was higher (sE-sel.: 35.59 +/- 9.5 ng/ml) than in a group of pregnant women (n 38) during the second and third trimester (sE-sel.: 30.58 +/- 13.3 ng/ml, p < 0.05) with 17-beta E2 concentration 11.96 +/- 7.18 ng/ml. The finding of lower sE-selectin levels which is a sign that the endothelium is not exposed to the action of inflammatory cytokines IL-1 or TNF may thus be associated with the active "control" of thrombophilia in pregnancy. When during pregnancy in conjunction with oestrogen levels changes in the lipid concentration were investigated a compensating mechanism could be observed. Hypercholesterolaemia and hypertriglyceridaemia in pregnant women was associated with a rise of oestrogen levels as well as of "cardioprotective" HDL-cholesterol (the HDL level was during the first trimester 1.31 +/- 0.26 nmol/l, in the second and third trimester 1.69 +/- 0.48 nmol/l, p < 0.0167).     

Contents of alpha-fetoprotein in the blood of pregnant women as a criterion of the presence of congenital heart defects in the fetus

alpha-Fetoprotein (AFP) was measured in the blood of 16 women pregnant with twins at various terms of gestation and 24 pregnant women whose fetuses were found to have anencephaly, patent spina bifida, gastroschisis, renal polycystosis, or Down's disease. In Down's disease AFP level was 7 ng/ml (0.17 multiple of medians, MoM) at 17 weeks gestation and 6 ng/ml (0.12 MoM) at 19 weeks. In the fetal abnormalities studied AFP level was 372 ng/ml on average (6.8 MoM) at 16 to 18 weeks gestation, this being about 10 times higher than the normal level. AFP level in twin pregnancy at the same period was 2.3 MoM. AFP measurements are important for the prenatal diagnosis of fetal status in order to plan follow-up of pregnancy and labor management.     

Effect of furosemide on the renal excretion of digoxin

Digoxin serum and urine levels were determined by radioimmunoassay in 6 subjects (4 patients with heart disease and 2 volunteers without heart disease) who had been maintained on oral digoxin (0.25 or 0.5 mg daily). Observations were made during a 3-day control period and then during 8 days of concomitant digoxin and oral furosemide (40 mg daily) therapy. Serum digoxin levels determined 10 and 24 hr after each dose of digoxin averaged 1.2+/-0.1 ng/ml (M+/-SE) during control and 1.3+/-0.1 during the last 3 days on digoxin and furosemide. The daily urinary excretion of digoxine averaged 51+/-6% of the oral dose during control and 52+/-6 during the entire period of furosemide administration. The renal clearance of digoxin and creatinine averaged 94+/-7 and 87+/-11 ml/min, respectively, during control; corresponding values were 88+/-8 and 85+/-9 for urine collections demonstrating a distinct diuretic effect of furosemide and 87+/-8 and 75+/-10 for urine collections not demonstrating such an effect during diuretic therapy. The results suggest that the diuretic effect of furosemide does not significantly affect the excretion of digoxin     

Leptin in human pregnancy: the relationship with gestational hormones

OBJECTIVES: The aims of the study were (1) to examine the relationship between leptin and placental hormones by measuring serial changes in serum levels of leptin during and after pregnancy and (2) to study the effects of several gestational hormones on leptin release from fully differentiated 3T3-L1 adipocyte cell cultures. STUDY DESIGN: Serum levels of leptin were measured throughout pregnancy and at 3 months post partum in 29 healthy women and were also measured in 18 healthy women at delivery by cesarean section and on postpartum day 3. In addition, 3T3-L1 mouse adipocytes were incubated for 24 hours in media containing various reproductive hormones and leptin production was measured. RESULTS: Serum leptin levels increased significantly (8.4 +/- 0.9 vs 13.5 +/- 1.5 ng/mL; P <.001) between the first 2 trimesters of pregnancy but not between the second and third trimesters. These changes in leptin did not correlate significantly with changes in body mass index. Leptin levels dropped significantly during the immediate postpartum period, from 34.1 +/- 4.9 at cesarean delivery to 7.3 +/- 1.4 ng/mL on postpartum day 3 (P <.001). Fasting insulin level did not correlate significantly with leptin level during pregnancy but did so during the postpartum period (r = 0.60; P <.05). Leptin secretion from 3T3-L1 adipocytes was increased significantly when cells were cultured with human chorionic gonadotropin (150%, P <.01) and also when they were cultured with estrogen (120%, P <.03). CONCLUSION: The data suggest that leptin production by adipose tissue is stimulated by several hormones of pregnancy, which may contribute to the increased leptin levels observed during gestation.     

Multivariate image analysis of magnetic resonance images with the direct exponential curve resolution algorithm (DECRA). Part 2: Application to human brain images

Seasonal levels of cortisol, growth hormone (GH), insulin like growth factor 1 (IGF-1), glucose, triiodothyronine (T3), free T3, thyroxine and free fatty acids (FFA) were measured every 3 weeks for 54 weeks in the plasma of five adult bulls, and four barren and five pregnant Alaskan reindeer (Rangifer tarandus) cows. Three consecutive samples were taken from each animal. Cortisol levels exhibited wide seasonal variation (9-45 ng/ml) [corrected] without any peak or difference in levels among groups. Rising levels were detected between the 3 consequent samples. Peak GH levels, detected during January and February, were higher in the non-pregnant group (54 ng/ml) than the pregnant (26 ng ml-1) and the male (27 ng ml-1) groups. Low GH levels (2-10 ng ml-1) were recorded between May and September. IGF-1 reached peak levels (715 ng ml-1) in males in August, in non-pregnant females in September (677 ng ml-1), and in the pregnant females in October (505 ng ml-1). Seasonal minima (404 in males, 172 and 93 in pregnant and non-pregnant groups) were detected in February. Glucose was fairly stable throughout the year (100-200 mg/100 ml). A rising levels were found between the three consecutive samples. Triiodothyronine (T3) (2.16-2.30 ng ml-1) peaked in all three groups during the spring and early summer, and minimal levels (0.61-0.97 ng ml-1) were detected from October to January. Conversely, thyroxine or free T3 did not exhibit seasonal variation. FFA fluctuated widely (97-1076 nmol l-1) throughout the year. Only in pregnant females were concentrations more stable (150-460 nmol l-1). Perhaps, because of ad libitum supply of food in captive reindeer, only T3 and GH exhibited pronounced seasonal fluctuations which could be related to the metabolic changes expected during the annual cycle.     

Endogenous estrogen modulates phenothiazine stimulated prolactin secretion

The role of endogenous estrogen in the regulation of serum prolactin concentration in man is controversial. To evaluate the possible effect of endogenous fluctuations in serum estrogen on the regulation of prolactin secretion, the authors determined phenothiazine stimulated prolactin secretion in 12 women in the early follicular phase of the menstrual cycle when estrogen levels were low (mean +/- SE E1 + E2 = 82 +/- 7 pg/ml) and compared it to the response during the late follicular phase when estrogen levels were higher (mean E1 + E2 = 320 +/- 63 pg/ml). Mean basal serum prolactin concentrations were similar in the early and late follicular phases of the cylcle (17 +/- 4 and 20 +/- 2 ng/ml, respectively). The integrated prolactin response following phenothiazine administration was significantly higher at mid-cycle (402 +/- 46 ng-hr/ml) than in the early follicular phase (317 +/0 46 ng-hr/ml, P less than .02). Thus, these studies suggest that endogenous estrogen secretion may play a role in the regulation of serum prolactin concentration in man.     

Tobacco use and other risk behaviors among adolescents in an STD clinic

OBJECTIVE: To test efficacy of murine monoclonal, rabbit polyclonal recombinant equine or human tumor necrosis factor-alpha (rETNF or rHTNF, respectively) antibodies to inhibit native equine tumor necrosis factor (TNF) activity. ANIMALS: 8 and 18 healthy adult horses for parts 1 and 2 of the study, respectively. PROCEDURES: In part 1, supernates from endotoxin-activated peritoneal macrophages were incubated with various dilutions of each rETNF antibody and subsequently tested for TNF activity. Serum was also obtained from a horse 1 hour after infusion with 20 ng of endotoxin/kg of body weight and was incubated with various dilutions of rabbit polyclonal rHTNF antibody. In part 2, 20 ng of endotoxin/kg was infused in horses during a 30-minute period. Fifteen minutes after the endotoxin infusion was initiated, 1 of 3 preparations was infused: 0.1 mg of rabbit polyclonal (rHTNF antibody/kg, 0.1 mg of human IgG/kg, or 500 ml of 5% dextrose. Clinical and hematologic data were collected for 24 hours. RESULTS: Compared with the monoclonal antibody, the rabbit polyclonal rETNF antibody was more effective in inhibiting TNF activity. The 50% effective doses of the murine monoclonal rETNF, rabbit polyclonal rETNF, and rabbit rHTNF antibodies were 1.8, 0.8, and 0.6 micrograms of antibody/ml, respectively. In part 2, endotoxin infusion resulted in significant alternations in all variables; however, differences among treatment groups were not significant. CONCLUSIONS AND CLINICAL RELEVANCE: Although murine monoclonal and rabbit polyclonal rETNF or rHTNF antibodies are capable of inhibiting native equine TNF activity in vitro, when given after initiation of endotoxemia, administration of 0.1 mg of rabbit polyclonal rHTNF/kg does not alter the response to infusion of endotoxin.