Mean Serum Luteinizing Hormone Concentrations Research Articles

Influences of Serotonin Hydrochloride on Adiponectin, Ghrelin and KiSS1 Genes Expression.

Background: Serotonin and kisspeptin stimulates gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) release while ghrelin and adiponectin inhibit them. In the present experimental study, the effects of central injection of serotonin were investigated on LH concentration, KiSS1, adiponectin, and ghrelin genes expression. Materials and Methods: Fifteen Wistar male rats in three groups received saline or serotonin hydrochloride via the third cerebral ventricle. Blood samples were collected via the tail vein. Serum LH concentration and relative gene expression were evaluated by radioimmunoassay and real-time polymerase chain reaction method, respectively. Results: Serotonin significantly increased the mean serum LH concentration and KiSS1 gene expression levels compared to the saline group. Serotonin significantly decreased the mean ghrelin and adiponectin genes expression levels compared to the saline group. Conclusion: The serotonergic pathway may have stimulatory effects on hypothalamic kisspeptin synthesis, partly via inhibiting hypothalamic ghrelin and adiponectin neural activity.

Influences of Serotonin Hydrochloride on Adiponectin, Ghrelin and KiSS1 Genes Expression

Background: Serotonin and kisspeptin stimulates gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) release while ghrelin and adiponectin inhibit them. In the present experimental study, the effects of central injection of serotonin were investigated on LH concentration, KiSS1, adiponectin, and ghrelin genes expression. Materials and Methods: Fifteen Wistar male rats in three groups received saline or serotonin hydrochloride via the third cerebral ventricle. Blood samples were collected via the tail vein. Serum LH concentration and relative gene expression were evaluated by radioimmunoassay and real-time polymerase chain reaction method, respectively. Results: Serotonin significantly increased the mean serum LH concentration and KiSS1 gene expression levels compared to the saline group. Serotonin significantly decreased the mean ghrelin and adiponectin genes expression levels compared to the saline group. Conclusion: The serotonergic pathway may have stimulatory effects on hypothalamic kisspeptin synthesis, partly via inhibiting hypothalamic ghrelin and adiponectin neural activity.[GMJ.2020;9:e1767]

Simultaneous Effect of Kisspeptin and Galanin on Serum Luteinizing Hormone and Testosterone Levels in Male Rats

Background: Galanin is a neuropeptide with a wide range of physiological functions that also has stimulatory effects on the reproductive axis. Kisspeptin is a crucial neuropeptide for the stimulation of the reproductive function. In the present study, the interaction of kisspeptin and the galanin signaling system was investigated on the mean serum luteinizing hormone (LH) and the testosterone concentrations in rats. Materials and Methods: Fifty-five male Wistar rats in 11 groups (n=5 per group) received saline, kisspeptin (1nmol), P234(1nmol), galanin(1nmol), galantide (1nmol) or simultaneous injections of them via third cerebral ventricle at 07:00 - 07:30. Blood samples were collected at 30 min following the injections. Hormone concentrations were measured using rat kit and the method of the radio-immunoassay (RIA). Results: Kisspeptin or galanin injection significantly increased both the mean serum LH and the testosterone concentration compared to saline (P<0.05). The co-administration of kisspeptin/galanin increased the mean serum LH and the testosterone concentration significantly compared to galanin or saline (P<0.05). The co-administration of kisspeptin/galanin decreased the mean serum LH concentration compared to kisspeptin, this reduction, however, was not statistically significant. Also, testosterone concentration declined in the kisspeptin/galanin group compared to kisspeptin group. Galantide or p234 injection decreases the mean serum LH and the testosterone concentration compared to galanin and kisspeptin, respectively. The co-administration of galantide/p234 lowers the mean serum LH concentration compared to saline. Conclusion: The interaction of hypothalamic galanin and kisspeptin signaling pathways may play an important role in the modulation of hormonal control of the hypothalamus-pituitary-gonadal axis. [GMJ. 2017;6(1):23-29]

Reproductive Hormonal Profile of Post-menopausal Women in Ebonyi State, Nigeria

Background: Assessment of the concentrations of reproductive hormones during postmenopause has been suggested as a confirmatory test for menopause due to Original Research Article British Journal of Medicine & Medical Research, 4(5): 1269-1278, 2014 1270 irregularities in rise and fall of sex hormones in menopausal transition. In this study, we assessed the concentrations of estrogen, progesterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) in post-menopausal women in Ebonyi state, Nigeria. In addition we tried to establish if relationships exist between the pituitary hormones and the ovarian (sex) hormones and between the reproductive hormones and age and body mass index (BMI). Method: The study population comprised forty post-menopausal women of mean age 59.6 years and forty young female adult controls of mean age 27.8 years. Blood samples were collected into heparin container and the serum used for the analysis of estrogen, progesterone, FSH and LH using ELISA method. Result: Post-menopausal women had significantly (P<0.001) higher mean serum FSH and LH concentrations compared to their controls. In contrast, the control group had significantly (P<0.001) higher progesterone and estradiol levels compared to the postmenopausal women. There was inverse correlation (P<0.01) between estradiol and FSH levels, but no significant correlations were observed between FSH and Progestrone; LH and Progestrone; and LH and Estradiol respectively. In addition, after adjusting for BMI, the concentrations of LH was significantly associated with age (P<0.01) but FSH, estradiol and progesterone levels were not. Furthermore, estradiol and FSH levels were significantly associated (P<0.001 and P<0.05) with BMI after controlling for age. Conclusion: The present findings underscore the importance of understanding the reproductive hormonal profile of post-menopausal women and the need to consider age and body mass when studying hormonal changes of menopausal women. These data may help clinicians make optimal therapeutic decisions for hormone replacement therapy and life-style changes that may reduce the risk of some of the conditions associated with menopause.

Long-Term Prognosis of Office Microlaparoscopic Ovarian Drilling (OMLOD) for Women with Polycystic Ovary Syndrome

Objective: There is considerable controversy about how long the beneficial effects of office microlaparoscopic ovarian drilling (OMLOD) under augmented local anesthesia last, compared to effects following drilling with the conventional 10-mL laparoscope using general anesthesia. Design: This prospective follow-up study was undertaken to investigate the long-term effects and prognosis of patients who underwent OMLOD. Methods: The study included 116 anovulatory women with polycystic ovary syndrome (PCOS) who underwent OMLOD between 2006 and 2010 (study group) and 34 anovulatory PCOS women diagnosed during the same period, who had not undergone OMLOD (comparison group). The hospital records were reviewed, and most patients received a transvaginal ultrasound scan and blood sampling to measure serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, androstenedione, and sex hormone-binding globulin. The results before and at different intervals, short- (<1 year), medium- (1–3 years) and long-term (3–5 years), after OMLOD were compared. Results: The LH:FSH ratio, mean serum concentrations of LH and testosterone, and free androgen index decreased significantly after OMLOD and remained low during the medium- and long-term follow-up periods, compared with the control group (FSH=5±1.6 international units (IU)/L, LH=13±6.2 IU/L, LH/FSH=2.6±1.4 and free androgen index=11.3±7.3). The mean ovarian volume decreased significantly (p<0.05) from 11 mL before OMLOD to 8.5 mL at medium-term and remained low (8.4 mL) at long-term follow-up. Conclusions: The beneficial endocrinologic and morphologic effects of OMLOD appear to be sustained for up to 5 years in most patients with PCOS. (J GYNECOL SURG 27:209)

Luteinizing hormone secretion as influenced by age and estradiol in the prepubertal gilt

The aim of this study was to determine if there is an age related reduction in the sensitivity of the negative feedback action of 17β-estradiol (estradiol) on luteinizing hormone (LH) secretion in the prepubertal gilt. Ovariectomized gilts at 90 ( n = 12), 150 ( n = 11) or 210 ( n = 12) days of age received estradiol benzoate (EB) osmotic pump implants 6/group and the remaining animals received vehicle control (C) implants except for 150-day C ( n = 5) on Day 0. On Day 10 blood samples were collected every 15 min for 8 h and serum LH and estradiol concentrations were measured. Serum estradiol concentrations averaged 5 ± 1, 5 ± 1 and 7 ± 2 pg/ml for the 90-, 150- and 210-day-old gilts implanted with estradiol, respectively, whereas, serum estradiol concentrations was undetectable in C gilts. Mean serum LH concentrations, basal LH concentrations and serum LH pulse amplitude were less in EB-treated gilts at all ages compared to control animals. In contrast, LH pulse frequency initially was less in EB-treated gilts but subsequently increased ( P < 0.04) with age (from 0.8 ± 0.2 at 90 days to 5.2 ± 0.2/8 h at 210 days), and at 210 days of age the pulse frequency was similar to C gilts. These results demonstrate an age related reduction in the sensitivity to the negative feedback action of estradiol on LH secretion and support the idea that the gilt conforms to the gonadostat hypothesis.

Effects of two different anaesthetics on serum concentrations of cortisol and luteinizing hormone in barrows and gilts

To determine if administration of the anaesthetic cocktail, telazol-ketamine-xylazine (TKX) and pentothal (PEN) decreases serum concentrations of luteinizing hormone (LH) in pigs, the following experiment was performed. On day 1, eight gilts and six barrows of similar weight (75 kg) were anaesthetized with TKX (1 mL/22.5 kg body weight [BW] intramuscularly) and indwelling jugular catheters were inserted. On days 2, 6 and 8 blood samples were taken every 20 min, for 4 h before pigs were administered saline (day 2) or anaesthetized with TKX (day 6) and PEN (8.9 mg/kg BW intravenously, day 8). Blood samples were taken every 20 min for 4 h following administration of saline and anaesthetics. Mean serum concentrations of LH and cortisol did not differ (P > 0.05) within barrows or gilts from before administration of saline (day 2) to following saline administration. Mean serum concentrations of LH and cortisol were not different (P > 0.05) within barrows and gilts before administration of TKX (pre-TKX) or PEN compared with day 2 samples. Following administration of TKX (post-TKX), mean serum concentrations of LH decreased (P < 0.05) and remained decreased for 140 min, while mean serum concentrations of cortisol increased (P < 0.05) post-TKX and remained elevated for 140 min. In gilts, mean serum concentrations of LH did not differ (P > 0.05) from pre- to post-TKX. However, mean serum concentrations of cortisol increased (P < 0.05) post-TKX in gilts and remained elevated for 240 min. Following administration of PEN, mean serum concentrations of LH and cortisol within barrows and gilts were not different (P > 0.05) from concentrations before administration of PEN. Administration of TKX to barrows and gilts increased serum concentrations of cortisol, but transient decreases in serum concentrations of LH were observed only in barrows, indicating gonadal status and/or sex may influence the ability of TKX to alter circulating concentrations of LH in pigs.

The relationship between secretory patterns of gonadotrophic hormones and the attainment of puberty in bull and heifer calves born early or late during the spring calving season

It was suggested that an early increase in gonadotrophin secretion in calves aged between 6 and 24 weeks might be critical for initiating developmental changes culminating in puberty. An early rise in luteinizing hormone (LH) release appears to be caused by an increase in LH pulse frequency in bull calves and by an increase in LH pulse amplitude in heifer calves. Previously we have found differences in the characteristics of the LH rise between prepubertal beef calves born in spring or fall; however, age at puberty was not affected by season of birth. Here we report the LH/FSH secretory patterns in prepubertal bull and heifer calves (Hereford x Charolais), born in March or April, respectively (i.e., early or late during the spring calving season; six animals of each sex born at each time). The bull calves of both groups reached puberty (defined as an attainment of scrotal circumference of ≥ 28 cm) at 43.2 ± 1.3 weeks of age ( P > 0.05). Age at puberty for March- and April-born heifer calves (defined as the age at which serum progesterone concentrations first exceeded 0.4 ng/ml) averaged 56.0 ± 1.4 weeks ( P > 0.05). Based on blood samples taken weekly from birth to 26 weeks of age, and then every other week until puberty, bull calves born in March exceeded April-born bull calves in mean serum LH concentrations at 6, 10 and 12 weeks of age ( P < 0.05). Mean FSH concentrations were greater ( P < 0.05) in March-born compared to April-born bull calves from 34 to 32 weeks before puberty. Mean serum LH (at 40, 42 and 56 weeks) and FSH concentrations (at 2, 10, 20, 22–26, 30 and 56 weeks of age) were greater ( P < 0.05) in heifer calves born in April than March. On the basis of frequent blood sampling (every 12 min for 10 h), heifer calves born in April exceeded March-born animals in mean LH and FSH concentrations, at 5 and 25 weeks, and LH pulse frequency, at 5, 10 and 25 weeks of age ( P < 0.05). None of the parameters of LH secretion (i.e., mean concentrations of LH, LH pulse frequency and amplitude based on frequent blood collection) differed between March- and April-born bull calves in this study ( P > 0.05). In summary, March-born bull calves had greater mean serum LH and FSH concentrations prior to 24 weeks of age than April-born calves. April-born heifer calves had greater mean serum concentrations of LH and FSH but this difference was not confined to the early postnatal period. Although there were significant differences in absolute amounts of LH secreted, there were no differences in the frequency of LH secretory pulses amongst March- and April-born bull calves and no differences in LH pulse amplitude in heifer calves born in March or April. As these particular parameters of LH secretion, as well as age at puberty, are not affected by the time or season of birth, they may be primary hormonal cues governing sexual development in bulls and heifers, respectively.

Influence of estradiol, progesterone, and nutrition on concentrations of gonadotropins and GnRH receptors, and abundance of mRNA for GnRH receptors and gonadotropin subunits in pituitary glands of beef cows.

Nutritionally induced anovulatory cows (n = 28) were used to determine the effect of steroids on regulation of synthesis and secretion of gonadotropins. Anovulatory cows were ovariectomized and received intravaginal inserts containing estradiol (E2), progesterone (P4), E2 and P4 (E2P4), or a sham intravaginal insert (C) for 7 d. Concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were quantified in serum and E2 and P4 were quantified in plasma. Cows were exsanguinated within 1 to 2 h after removal of intravaginal inserts and pituitary glands were collected and stored at -80 degrees C until messenger ribonucleic acid (mRNA) for gonadotropin-releasing hormone receptor (GnRH-R) and gonadotropin subunits, pituitary content of GnRH-R, and LH and FSH were quantified. Pituitary glands from five proestrous cows were harvested to compare gonadotropin characteristics between ovariectomized, anovulatory cows and intact cows. Plasma concentrations of E2 were greater (P < 0.05) in E2-treated cows than in sham-treated cows. Concentrations of P4 were greater (P < 0.05) in cows treated with P4 than in sham-treated cows. Mean serum concentrations of LH and FSH were not significantly influenced by steroid treatments. However, frequency of LH pulses of ovariectomized, nutritionally induced anovulatory cows was increased (P < 0.05) by treatment with E2 and amplitude of LH pulses was greater (P < 0.05) in cows treated with E2 or P4 than in cows treated with E2P4 or sham-treated. Quantity of mRNA for LHbeta in the pituitary gland was greater when cows were treated with P4. Concentrations of LH in the pituitary gland were not affected by steroid treatments; however, pituitary concentrations of FSH were less (P < 0.1) in E2 cows than in sham-treated cows. The number of GnRH-R was increased (P < 0.05) in cows treated with E2, but P4 treatment did not influence the number of GnRH-R. Abundance of mRNA for GnRH-R, common alpha-subunit, and FSHbeta were not affected by treatments. Pituitary concentrations of LH were greater (P < 0.05) and concentrations of FSH were less (P < 0.05) in proestrous cows than in ovariectomized, anovulatory cows treated with or without steroids. Abundance of mRNA for GnRH-R, common alpha-subunit, LHbeta and FSHbeta were similar for proestrous and anovulatory cows. We conclude that treatment of nutritionally induced anovulatory cows with progesterone and estradiol may cause pulsatile secretion of LH.

Elevated serum levels of tumor necrosis factor alpha in normal-weight women with polycystic ovary syndrome

Since an increase in tumor necrosis factor alpha (TNFα) expression has been associated with insulin resistance, this study was undertaken to determine the status of circulating TNFα and the relationship of TNFα with insulin levels, body weight, or both in women with polycystic ovary syndrome (PCOS). Fasting serum samples were analyzed in 34 subjects with PCOS, of whom 22 were obese (body mass index [BMI] >27 kg/m 2), and in 40 normal control women, of whom 20 were obese. Women with PCOS exhibited a significantly ( P < .02) higher mean serum TNFα concentration compared with the controls. The serum TNFα level and BMI were directly correlated in women with PCOS ( r = .48, P < .005) and highly correlated in controls ( r = .78, P < .001). When subjects were classified by body weight, the mean serum TNFα concentration was significantly ( P < .001) elevated in normal-weight women with PCOS compared with normal-weight controls. On the other hand, mean serum TNFα concentrations in obese women with PCOS and obese controls were similar and significantly ( P < .02) higher than in normal-weight women with PCOS. A direct correlation between serum fasting insulin and TNFα was evident in controls ( r = .35, P < .03), but not in women with PCOS. However, in the subgroup of obese women with PCOS, fasting insulin directly correlated ( r = .49, P < .03) with TNFα and the median fasting serum insulin concentration was significantly ( P < .05) higher compared with the level in normal-weight women with PCOS and all controls. Fasting insulin and TNFα were no longer correlated in controls as a group and in obese women with PCOS when controlling for body weight. Serum TNFα did not correlate with luteinizing hormone (LH), testosterone (T), or dehydroepiandrosterone sulfate (DHEAS) in women with PCOS. However, serum insulin was significantly correlated ( r = .49, P < .0004) with T and the BMI exhibited a trend for correlation with serum T ( r = .33, P = .05) in women with PCOS. Finally, the mean serum LH concentration was significantly ( P < .02) higher in normal-weight women with PCOS versus obese women with PCOS, and serum LH levels exhibited a trend for an inverse correlation with the BMI ( r = .31, P = .09) in women with PCOS. We conclude that (1) serum TNFα is increased in normal-weight women with PCOS and is even higher in obese individuals regardless of whether they have PCOS; (2) factors other than obesity are the cause of elevated serum TNFα in normal-weight women with PCOS; and (3) whereas increased circulating TNFα may mediate insulin resistance in obesity, which may in turn promote hyperandrogenism in obese women with PCOS, it remains to be demonstrated whether this is also the case in normal-weight women with PCOS.

Aging alters feed-forward and feedback linkages between LH and testosterone in healthy men.

To discern the effect of aging on coordinate luteinizing hormone (LH) and testosterone secretion, we sampled healthy older men (age 62-74 yr, n = 11) and young controls (age 21-34 yr, n = 13) every 2.5 min overnight. Deconvolution analysis and cross-correlation were used to relate serum LH concentrations to calculated testosterone secretion rates (feed-forward stimulation), as well as serum testosterone concentrations to computed LH secretion rates (feedback inhibition). Despite statistically similar mean serum LH and testosterone concentrations in the young and older men, older individuals had diminished feed-forward stimulation of LH concentrations on calculated testosterone secretion rates, as well as delayed feedback inhibition of testosterone concentrations on computed LH secretion rates.

Neural levels of cholecystokinin peptide and mRNA during dietary stimulation of growth and LH secretion in growth-retarded lambs

Chronic feed restriction of prepubertal male lambs adversely affects reproductive development by inhibiting the pulsatile release of luteinizing hormone (LH). Because this effect can be reversed by ad libitum feeding, the associations between diet-induced increases in LH release and concurrent changes in body weight gain, serum glucose, CCK peptide, and CCK mRNA were examined. Neonatally castrated male lambs received a restricted ration to maintain their respective weaning weights beginning at 8 wk of age. At 23 wk of age, lambs were assigned randomly to receive additional feed equivalent to 0%, 50%, or 100% of their previous daily intake. Serum profiles of LH and glucose were determined 2 and 4 wk after onset of the increased intakes. At 27 wk of age, lambs were euthanized and both hypothalamic and cerebral cortical tissues were collected for analysis of CCK peptide and CCK mRNA. With additional intakes, body weight gain increased (P < 0.001) proportional to the graded increases in feed intake. Mean serum LH concentrations, LH peak frequencies, and serum glucose concentrations also increased (P < 0.05) progressively among the 0%, 50%, and 100% dietary intake groups. Neither CCK peptide nor CCK mRNA differed (P > 0.05) among dietary groups suggesting that endogenous CCK in the whole hypothalamus did not change with the feeding-induced increase in LH release. Concentrations of CCK peptide in cerebral cortex were greater (P < 0.05) than hypothalamic concentrations, but there were no differences between hypothalamus and cerebral cortex in the relative abundance of CCK mRNA. In summary, dietary stimulation of growth-retarded male lambs resulted in progressive increases in body weight gain, mean serum LH, serum glucose, and LH peak frequencies. Because hypothalamic levels of CCK peptide and CCK mRNA did not change during feeding-induced secretion of LH, endogenous CCK in the hypothalamus seems unlikely as a chronic mediator of nutrition-sensitive LH release.

Luteinizing hormone, follicle-stimulating hormone, testosterone and dihydrotestosterone during testicular descent in the pig fetus.

To investigate the relationship between gonadotrophins, androgens and testicular descent in the pig fetus, serum concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), and serum concentrations and testicular content of testosterone (T) and 5 alpha-dihydrotestosterone (DHT) were determined by radioimmunoassay in 95 fetuses (48 males, 47 females) between Day 60 and Day 90 post coitum (p.c.). The testes were descended in 0% of fetuses at Day 60, 8% of fetuses at Day 70, 40% of fetuses at Day 80 and 87% of fetuses at Day 90 p.c. There was a significant increase in mean serum concentrations of LH in both male and female fetuses from Day 60 to Day 90, with a significant difference in mean serum concentrations of LH between male fetuses with a body mass < 350 g (4% of testes descended) and those with a body mass > 450 g (87% of testes descended), but not between male and female fetuses < 350 g or > 450 g in body mass. There was no significant difference in mean serum concentrations of FSH between male and female fetuses. Mean serum concentrations of T were significantly higher in male fetuses at Day 60 than in those at Days 70-90, with no significant difference in serum concentrations of DHT from Day 60 to Day 90 p.c. Testicular content of T and DHT showed a non-linear increase from Day 60 to Day 90 p.c. Although the serum concentration of T is elevated before, and decreased during, the period of descent, the testicular content of T and DHT increases during the period of descent, indicating that serum concentrations of LH and FSH may have an indirect effect on descent by stimulating testicular androgen synthesis.

Effects of a gonadotropin-releasing hormone agonist on serum luteinizing hormone concentrations in female white-tailed deer

As part of a study to develop contraceptive technologies for white-tailed deer ( Odocoileus virginianus), the potential for a gonadotropin-releasing hormone (GnRH) agonist, Histrelin (HIS), to inhibit luteinizing hormone (LH) secretion in does was investigated. Three experiments were conducted during the breeding season to determine the effects of dose, route, and pattern of administration of HIS on serum LH concentrations. The first experiment included six treatments, each given as an i.v. injection: 0.1, 1, 10, and 100 μg HIS, 10 μg GnRH, and saline (control); the second experiment included four treatments, as s.c. injection: 10, 50, and 100 μg HIS, and saline. Maximum LH concentrations occurred by 240 min after injection in both experiments. At 360 min post-injection, serum LH concentrations were still elevated in the 10 and 100 μg i.v. HIS and the 50 and 100 μg s.c. HIS groups ( P < 0.05) as compared with controls. In a third experiment 8.3 μg HIS h −1 (200 μg HIS per day) were administered s.c. continuously for 14 days to four does; controls received continuous saline infusions ( n = 3). On Day 1 (Day 0 is day of minipump insertion), the HIS group had a higher mean serum LH concentration than controls (16.0 ± 5.3 vs. 0.9 ± 0.4 ng/ml, respectively; P = 0.06). By Day 2 mean LH concentrations did not differ between the groups and remained at base line for the duration of infusion. On Day 10 both groups received a s.c. injection of 100 μg HIS. At 240 min the mean serum LH concentration for controls was 17.8 ± 3.3 ng/ml and was still elevated at 600 min. In contrast, serum LH concentrations in the HIS group remained at base line (0.5 ± 0 ng/ml). The data indicate that HIS, a GnRH agonist, acts as an LH secretagogue in white-tailed deer, as evidenced by the increase in serum LH concentrations following a single injection of HIS. Furthermore, continuous s.c. administration of HIS during the breeding season inhibits LH secretion in does, and could be a useful tool for preventing ovulation, thereby preventing pregnancy of deer.

Elevated inhibin concentration in the follicular fluid of dairy cows with chronic cystic ovarian disease

This study compared serum and follicular fluid inhibin and gonadotropin profiles between chronic cystic ovarian diseased (CCOD) and normal cyclic dairy cows. Blood samples and follicular fluid were collected from CCOD cows (n=15) and cyclic cows in the follicular phase of the estrous cycle (control, n=6) and analyzed for inhibin, follicle stimulating hormone (FSH) and luteinizing hormone (LH) concentrations. There was a significant increase in inhibin and a decrease in FSH and LH concentrations in the follicular fluid of CCOD cows compared with those of cyclic cows (P < 0.05). Mean serum inhibin, FSH and LH concentrations between CCOD and cyclic cows were not differnt (P > 0.05), however, there was a tendency for serum inhibin to be higher and FSH to be lower in CCOD cows compared to cyclic animals (P < 0.1). The FSH pulse frequency also was lower in CCOD cows than in cyclic cows (P < 0.05). These data suggest that increased production of inhibin from cystic follicles of CCOD cows alters pituitary FSH secretion and subsequently reduces the concentration of FSH in follicular fluid. As a result, decreased FSH stimulation at the ovarian level could ultimately lead to the reduction in follicular LH and FSH receptor concentrations, resulting in abnormal follicular steroidogenesis in CCOD dairy cows.

Endocrinology: The effect of nalmefene on pulsatile secretion of luteinizing hormone and prolactin in men

Luteinizing hormone (LH) and prolactin are released in pulses which are relatively synchronous in the luteal phase of the menstrual cycle in women. The concordance of LH and prolactin pulses in normal men has not been reported. The objectives of this study were firstly to determine whether LH and prolactin pulses are synchronous in men, and secondly to examine the effects of naloxone and a new orally active opiate antagonist, nalmefene, on LH and prolactin release in men. Three groups of normal male subjects received saline infusion (control n = 5), naloxone infusion (2 mg/h; n = 5) or nalmefene (10 mg p.o.; n = 6). Blood samples were collected every 15 min for 2 h before and 6 h after study medication for determination of LH, prolactin and testosterone by radioimmunoassay. Both naloxone and nalmefene resulted in a significant increase in LH pulse frequency and in mean serum LH and testosterone concentrations with no change in LH pulse amplitude, prolactin pulse frequency or amplitude. In controls, 61% of LH pulses were synchronous with prolactin pulses. There was a decrease in concomitance of LH and prolactin pulses with naloxone (48%) and nalmefene (24%; P < 0.025) administration. In contrast, 52% of prolactin pulses were concomitant with LH pulses in controls, while naloxone (100%) but not nalmefene (67%) resulted in a significant (P < 0.01) increase in pulse synchrony. The difference observed between naloxone and nalmefene on prolactin--LH pulse synchrony is probably due to differential opioid receptor activity at the pituitary and hypothalamic level.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypothalamic proopiomelanocortin mRNA levels in suckled or nonsuckled beef cows: A preliminary study

This study was conducted to determine proopiomelanocortin (POMC) mRNA levels in the preoptic and hypothalamic brain regions of postpartum anestrous cows. An additional objective was to determine if calf suckling influences POMC mRNA concentration in these regions. Twenty cows were randomly assigned to suckled and nonsuckled treatment groups and slaughtered between 30 and 36 days postpartum. Serum luteinizing hormone (LH) concentrations were determined from blood collected every 15 minutes for 8 hours, starting 20 hours prior to slaughter. POMC mRNA levels in brain tissues were determined by dot blots. Serum LH concentrations between nonsuckled and suckled cows were 1.3 ± 0.2 and 0.9 ± 0.1 ng·ml −1 (mean ± SEM; P = 0.19), respectively. The POMC gene is expressed in the hypothalamus of postpartum anestrus cows with POMC mRNA levels higher (P<0.05) in the hypothalamus than in the preoptic region. Hypothalamic POMC mRNA levels tended (P = 0.12) to be lower in nonsuckled (14.9 ± 3.8 ADU) than in suckled cows (23.5 ± 3.6 ADU). Covariate analysis indicated (P = 0.10) that as mean serum LH concentrations increased, hypothalamic POMC mRNA levels decreased.

Effects of naloxone on circulating gonadotrophin concentrations in prepubertal heifers.

The pattern and opioidergic control of the secretion of gonadotrophins in prepubertal heifer calves were examined. Ten age-matched Hereford heifer calves were weighed and a blood sample was taken every 2 weeks from 2 to 25 weeks of age and then weekly until 60 weeks of age. At 60 weeks, a fertile bull was introduced and at 75 weeks of age pregnancy diagnosis was performed by transrectal ultrasonography. At 4, 12, 18, 24 and 32 weeks of age, the opioid antagonist naloxone was injected (i.v., n = 5; 1 mg kg-1 body weight) each hour for 12 h. Control heifers received sterile saline at the same ages. Blood samples were collected every 12 min for the 12 h treatment and serum samples were analysed for luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Samples taken once every 2 weeks from 2 to 60 weeks were analysed for LH, FSH and oestradiol, and weekly samples were taken for progesterone determination. There was no effect of naloxone on the age at puberty, which was 56.2 +/- 0.7 weeks at a body weight of 388.5 +/- 8.0 kg. The mean age at conception was 63.4 +/- 0.5 weeks. On the basis of samples taken every other week, serum concentrations of LH were high at 10 weeks and between 40 and 60 weeks of age. From the periods of intensive blood collection, the early rise in mean serum concentrations of LH appeared later at 12 and 18 weeks of age and was caused by a rise in LH pulse amplitude.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of suckling and of a long interval after ovariectomy on hypothalamo-hypophyseal responsiveness to naloxone, morphine and GnRH in beef cows

The response of serum luteinizing hormone (LH) to morphine, naloxone and gonadotropin-releasing hormone (GnRH) in ovariectomized, suckled (n=4) and nonsuckled (n=3) cows was investigated. Six months after ovariectomy and calf removal, the cows were challenged with 1mg, i.v. naloxone/kg body weight and 1 mg i.v. morphine/kg body weight in a crossover design; blood was collected at 15-minute intervals for 7 hours over a 3-day period. To evaluate LH secretion and pituitary responsiveness, 5 μg of GnRH were administered at Hour 6 on Day 1. On Days 2 and 3, naloxone or morphine was administered at Hour 3, followed by GnRH (5 μg/animal) at Hour 6. Mean preinjection LH concentrations (3.6 ± 0.2 and 4.7 ± 0.2 ng/ml), LH pulse frequency (0.6 ± 0.1 and 0.8 ± 0.1 pulses/hour) and LH pulse amplitude (2.9 ± 0.5 and 2.9 ± 0.6 ng/ml) were similar for suckled and nonsuckled cows, respectively. Morphine decreased (P < 0.01) mean serum LH concentrations (pretreatment 4.2 ± 0.2 vs post-treatment 2.2 ± 0.2 ng/ml) in both suckled and nonsuckled cows; however, mean serum LH concentrations remained unchanged after naloxone. Nonsuckled cows had a greater (P < 0.001) LH response to GnRH than did suckled cows (area of response curve: 1004 ± 92 vs 434 ± 75 arbitrary units). We suggest that opioid receptors are functionally linked to the GnRH secretory system in suckled and nonsuckled cows that had been ovariectomized for a long period of time. However, gonadotropin secretion appears not to be regulated by opioid mechanisms, and suckling inhibits pituitary responsiveness to GnRH in this model.

Long-term changes in the quality and quantity of both trabecular and cortical bone in the young ovariectomized cynomolgus monkey: A comparison of histomorphometric and density fractionation techniques

It has been suggested that there is a difference in the interaction between sex steroids and gonadotropin secretion between transsexual and heterosexual women. In this study we tested whether there is a difference in the pulsatile release characteristics of luteinizing hormone (LH) and in ovarian steroid concentrations between 16 female-to-male (f-to-m) transsexuals and eight eugonadal heterosexual women during the early follicular phase of the menstrual cycle. Blood samples for LH determination were collected every 10 min for 7 hr in the transsexual group, and every 10 min for 6 hr in the heterosexual group. There were no significant differences between the transsexual and heterosexual group in mean serum LH concentration (6.9±2.4 U/l vs. 7.5±2.6 U/l), mean LH nadir interval (77±37 min vs. 70±16 min), and mean LH pulse amplitude (2.9±1.1 U/l vs. 3.0±1.1 U/l). Serum estrone, 17-β-estradiol, testosterone, progesterone and FSH concentrations also did not differ between the two groups. There also was not a higher prevalence of polycystic ovarian disease in our f-to-m transsexual group than in the general population.