Effect of Short Agonist Stop (SAS) Protocol in a Patient Having an Allergic Reaction From Conventional Ovarian Stimulating Hormone

The case study examined a 32-year-old female and her 35-year-old partner who had experienced infertility attributed to the wife's irregular ovulation. Despite the male partner demonstrating normal reproductive parameters, he had a medical history involving hypertension. The woman also had a history of hypertension and chikungunya, which was accompanied by fever and joint pain in 2019. Due to the woman's allergic reaction to traditional ovulation stimulatory medications, the approach to assisted reproductive technologies (ART) had shifted towards employing the short agonist stop (SAS) regimen. Controlled ovarian stimulation had been achieved by administering recombinant follicular hormone, gonadotropin-releasing hormone (GnRH), and estrogen. The SAS protocol had been introduced to counter premature ovulation and synchronize follicular development. Following two successful ovum pickup procedures resulting in the retrieval of six embryos, the initial frozen embryo transfer took place in April 2022. Daily progesterone supplementation had been administered to sustain the patient's luteal phase. A subsequent human chorionic gonadotropin (β-hCG) test performed on the 14th day post-embryo transfer confirmed a positive pregnancy diagnosis, with a measured outcome of 2026 mIU/mL. This case highlighted the potential impact of medication allergies on fertility outcomes and underscored the unique approach of the SAS protocol in managing allergic responses during in vitro fertilization (IVF) procedures. Despite the patient's history of allergic reactions to conventional ovulation stimulatory medications, the study concluded that the implementation of the brief agonist stop strategy had resulted in a successful clinical pregnancy.

Effect of Prebiotic Dietary Supplement Acacia senegal on Hormonal and Metabolic Markers in Polycystic Ovary Syndrome Patients: A Pilot Study

Background The most prevalent endocrine condition affecting women of reproductive age is polycystic ovarian syndrome (PCOS), which is linked to a variety of metabolic abnormalities. Although the pathogenesis of PCOS is not fully understood, it is known that oxidative stress, altered gut microbiome, and increased gonadotrophin-releasing hormone play a significant role. Gum arabic (GA) is an edible, dried, gummy exudate from the Acacia senegal tree, well-known for its prebiotic and antioxidant effects. The main objective of the study was to assess the changes in hormonal and metabolic profiles in PCOS patients after the ingestion of gum arabic. Method This was a clinical trial conducted on fifteen patients suffering from PCOS, with a mean age of 27.8 years (20-39 years). All patients experienced irregular cycles. Hormonal and metabolic markers (follicular stimulating hormone (FSH), luteinizing hormone (LH), total testosterone (TT), fasting insulin, total cholesterol (TC), and glycosylated hemoglobin (HBA1c) were measured before and after the ingestion of gum arabic (30 g/day of GA dissolved in 250 ml water for eight weeks) on the second day of the menstrual cycle after granting ethical approval from the National Medicine and Poisons Board and from the participants of the study. Results The study demonstrated a significant decrease in the luteinizing hormone level, FSH/LH ratio, and cholesterol pre- and post-gum arabic ingestion (p-values 0.001, 0.013, and 0.007, respectively). Follicular stimulating hormone slightly reduced post-ingestion with no significant difference (p-value 0.414). No significant changes were seen in the testosterone, insulin, or HBA1c levels. Conclusion The study concluded that gum arabic ingestion for eight weeks decreases the luteinizing hormone and LH/FSH ratio and improves the metabolic profile by reducing the cholesterol level in PCOS patients.

Pseudo-pheochromocytoma due to obstructive sleep apnea: a case report

SUMMARY

Obstructive sleep apnea (OSA) is a condition of intermittent nocturnal upper airway obstruction. OSA increases sympathetic drive which may result in clinical and biochemical features suggestive of pheochromocytoma. We present the case of a 65-year-old male with a 2.9-cm left adrenal incidentaloma on CT, hypertension, symptoms of headache, anxiety and diaphoresis, and persistently elevated 24-h urine norepinephrine (initially 818 nmol/day (89-470)) and normetanephrine (initially 11.2 µmol/day (0.6-2.7)). He was started on prazosin and underwent left adrenalectomy. Pathology revealed an adrenal corticoadenoma with no evidence of pheochromocytoma. Over the next 2 years, urine norepinephrine and normetanephrine remained significantly elevated with no MIBG avid disease. Years later, he was diagnosed with severe OSA and treated with continuous positive airway pressure. Urine testing done once OSA was well controlled revealed complete normalization of urine norepinephrine and normetanephrine with substantial symptom improvement. It was concluded that the patient never had a pheochromocytoma but rather an adrenal adenoma with biochemistry and symptoms suggestive of pheochromocytoma due to untreated severe OSA. Pseudo-pheochromocytoma is a rare presentation of OSA and should be considered on the differential of elevated urine catecholamines and metanephrines in the right clinical setting.

LEARNING POINTS

Obstructive sleep apnea (OSA) is a common condition among adults. OSA may rarely present as pseudo-pheochromocytoma with symptoms of pallor, palpitations, perspiration, headache, or anxiety. OSA should be considered on the differential of elevated urine catecholamines and metanephrines, especially in patients with negative metaiodobenzylguanidine (MIBG) scan results.

374 Effects of maternal nutrition on secretion of leptin in the neonatal heifer and interaction of maternal and postnatal nutrition on age at puberty and postpubertal secretion of luteinizing hormone

Nutrition during gestation and early postnatally can program developmental changes in the offspring that persist until adult life. Here we tested the hypotheses that maternal nutritional during the second and third trimesters of gestation 1) affects neonatal secretion of leptin in heifer offspring, and 2) interacts with dietary energy intake during the juvenile period to affect age at puberty and postpubertal pulsatile secretion of luteinizing hormone (LH) in heifers. Bos indicus-influenced beef cows (n = 108) in 3 replicates bearing heifer fetuses were assigned randomly to receive low (L), moderate (M), or high energy (H) diets to achieve body condition scores (BCS) of 3–3.5 (thin; n = 36), 5.5–6 (moderate; n = 36), or 7.5–8 (obese; n = 36) by the second trimester of gestation until calving. Heifer offspring were weaned at 3–3.5 months of age and assigned randomly to either a high- (H; 1 kg/day) or low-gain (L; 0.5 kg/day) diet for 5 months. Blood samples from a subgroup of 30 heifers (Exp. 1) from cows in each maternal treatment (n = 10/treatment) were collected once every 2–3 days for 2 weeks after birth. In Exp. 2, 18 heifers representing 3 of the maternal × postnatal groups (HH, MH and LL) were ovariectomized and received estradiol replacement (OVX+E) after puberty. Pulsatile secretion of LH was evaluated for 5.5 hours. Maternal nutrition did not affect postnatal circulating leptin. Based on two replicates (n = 61), postnatal diets had the greatest effect on age at puberty (L > H; P < 0.001), with a lesser maternal diet effect (P < 0.10), although LL > HH by 99 days. None of the characteristics of pulsatile LH secretion differed among treatments in OVX + E heifers. Dietary effects on age at puberty were not associated with hormonal characteristics evaluated in these initial studies.

Acromegaly remission, SIADH and pituitary function recovery after macroadenoma apoplexy

Summary

Pituitary apoplexy is a rare but potentially life-threatening clinical syndrome characterised by ischaemic infarction or haemorrhage into a pituitary tumour that can lead to spontaneous remission of hormonal hypersecretion. We report the case of a 50-year-old man who attended the emergency department for sudden onset of headache. A computed tomography (CT) scan at admission revealed pituitary haemorrhage and the blood test confirmed the clinical suspicion of acromegaly and an associated hypopituitarism. The T1-weighted magnetic resonance imaging (MRI) showed the classic pituitary ring sign on the right side of the pituitary. Following admission, he developed acute-onset hyponatraemia that required hypertonic saline administration, improving progressively. Surprisingly, during the follow-up, IGF1 levels became normal and he progressively recovered pituitary function.

Learning Points

Patients with pituitary apoplexy may have spontaneous remission of hormonal hypersecretion. If it is not an emergency, we should delay a decision to undertake surgery following apoplexy and re-evaluate hormone secretion. Hyponatraemia is an acute sign of hypocortisolism in pituitary apoplexy. However, SIADH although uncommon, could appear later as a consequence of direct hypothalamic insult and requires active and individualised treatment. For this reason, closely monitoring sodium at the beginning of the episode and throughout the first week is advisable to guard against SIADH. Despite being less frequent, if pituitary apoplexy is limited to the tumour, the patient can recover pituitary function previously damaged by the undiagnosed macroadenoma.

Acute recapitulation of the hyperinsulinemia and hyperlipidemia characteristic of metabolic syndrome suppresses gonadotropins

OBJECTIVE

To determine the effect of lipid/heparin versus saline infusion, with or without concurrent euglycemic hyperinsulinemia, on serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Obesity is associated with hyperlipidemia, insulin resistance, and relative hypogonadotropic hypogonadism. It was hypothesized that acutely elevated fatty acids and insulin would impair gonadotropin secretion.

METHODS

Regularly cycling women and men without obesity underwent a crossover 6-hour infusion study over four visits. Participants received infusions of saline-control, lipid/heparin, insulin, and lipid/heparin plus insulin. Serum FSH and LH were measured by immunoassay.

RESULTS

In women (n = 10), infusion of lipid plus insulin significantly reduced LH, from 4.6 IU/L (3.7-5.4) (mean [95% confidence interval]) to 3.3 IU/L (2.3-4.4); P = 0.03, and FSH, from 3.9 IU/L (3.2-4.6) to 3.1 IU/L (2.3-3.8); P = 0.03, compared to saline-control. Similarly, in men (n = 10), LH, 3.3 IU/L (2.4-4.1), and FSH, 2.1 IU/L (1.4-2.8), were significantly reduced after the combined infusion (2.2 [1.3-3.1] IU/L and 1.5 [0.8-2.1] IU/L; P = 0.03, P = 0.02, respectively). Neither lipid nor insulin alone significantly impacted gonadotropin levels compared to saline-control.

CONCLUSIONS

Hyperinsulinemia combined with elevated lipids acutely suppresses LH and FSH, providing a possible mechanism underlying the relative hypogonadotropic hypogonadism of obesity. Effects of insulin on the hypothalamic-pituitary-gonadal axis may be dependent on the concomitant metabolic environment.

Leap of Faith: Does Serum Luteinizing Hormone Always Accurately Reflect Central Reproductive Neuroendocrine Activity?

The function of the central aspects of the hypothalamic-pituitary-gonadal axis has been assessed in a number of ways including direct measurements of the hypothalamic output and indirect measures using gonadotropin release from the pituitary as a bioassay for reproductive neuroendocrine activity. Here, methods for monitoring these various parameters are briefly reviewed and then examples presented of both concordance and discrepancy between central and peripheral measurements, with a focus on situations in which elevated gonadotropin-releasing hormone neurosecretion is not reflected accurately by pituitary luteinizing hormone release. Implications for the interpretation of gonadotropin data are discussed.

Luteinizing hormone and human chorionic gonadotropin: distinguishing unique physiologic roles

Luteinizing hormone (LH) and human chorionic gonadotropin (hCG) are integral components of the hypothalamic-pituitary-gonadal axis, which controls sexual maturation and functionality. In the absence of signaling through their shared receptor, fetal sexual differentiation and post-natal development cannot proceed normally. Although they share a high degree of homology, the physiologic roles of these hormones are unique, governed by differences in expression pattern, biopotency and regulation. Whereas LH is a key regulator of gonadal steroidogenesis and ovulation, hCG is predominantly active in pregnancy and fetal development. Emerging evidence has revealed endogenous functions not previously ascribed to hCG, including participation in ovulation and fertilization, implantation, placentation and other activities in support of successful pregnancy. Spontaneous and induced mutations in LH, hCG and their mutual receptor have contributed substantially to our understanding of reproductive development and function. The lack of naturally occurring, functionally significant mutations in the β-subunit of hCG reinforce its putative role in establishment of pregnancy. Rescue of reproductive abnormalities resulting from aberrant gonadotropin signaling is possible in certain clinical contexts, depending on the nature of the underlying defect. By understanding the physiologic roles of LH and hCG in normal and pathologic states, we may better harness their diagnostic, prognostic and therapeutic potential.

Endocrine profile following stimulation with recombinant follicle stimulating hormone and luteinizing hormone versus highly purified human menopausal gonadotropin

BACKGROUND

Luteinizing hormone (LH) activity in human menopausal gonadotropin (hMG) preparations is derived from human chorionic gonadotropin (hCG) rather than LH. Therefore, we aimed to determine whether there are similarities in the endocrine and follicular profiles of serum and follicular fluid from controlled ovarian stimulation with the recombinant gonadotropins follicle-stimulating hormone plus luteinizing hormone (rFSH + rLH) or highly purified human menopausal gonadotropin (HP-hMG).

METHODS

We performed a prospective observational study with 50 oocyte donors that received either a combination of recombinant gonadotropins (rFSH + rLH) or a mixture of urinary gonadotropins (HP-hMG) plus purified urinary FSH (uFSH). Results were analyzed using Student's t-test to compare continuous variables and the chi-squared test to compare proportions. P-values < 0.05 were considered statistically significant.

RESULTS

Although more oocytes were retrieved after treatment with recombinant than urinary gonadotropins (16.5 vs. 11.8; P = 0.049), a higher proportion of metaphase II ova (71.2% vs. 80.6%; P = 0.003) were obtained using urinary gonadotropins. On day 6 and on the day of triggering, serum steroid hormone levels were slightly but not significantly elevated in the recombinant group compared with the urinary group. In follicular fluid, no statistical differences were observed for intra-follicular levels of steroid hormones between the two protocols; ongoing pregnancy rates were similar (46.1% vs. 46.1%).

CONCLUSIONS

Our data suggest that endocrinological and follicular profiles do not differ between rFSH + rLH and HP-hMG stimulation.

A role for neurokinin B in pulsatile GnRH secretion in the ewe

The recent description of infertility in humans with loss-of-function mutations in genes for neurokinin B (NKB) or its receptor (NK3R) has focused attention on the importance of this tachykinin in the control of GnRH secretion. In a number of species, NKB neurons in the arcuate nucleus also produce two other neuropeptides implicated in the control of GnRH secretion: (1) kisspeptin, which is also essential for fertility in humans, and (2) dynorphin, an inhibitory endogenous opioid peptide. A number of characteristics of this neuronal population led to the hypothesis that they may be responsible for driving synchronous release of GnRH during episodic secretion of this hormone, and there is now considerable evidence to support this hypothesis in sheep and goats. In this article, we briefly review the history of work on the NKB system in sheep and then review the anatomy of NKB signaling in the ewe. We next describe evidence from a number of species that led to development of a model for the role of these neurons in episodic GnRH secretion. Finally, we discuss recent experiments in sheep and goats that tested this hypothesis and led to a modified version of the model, and then broaden our focus to briefly consider the possible roles of NKB in other species and systems.

Predictive value of hormonal parameters for live birth in women with unexplained infertility and male infertility

BACKGROUND

Infertile women might get pregnant sometime after fertility treatment, but today, there is no prediction model on who will eventually have children. The objective of the present study was to characterize hormone levels in an arbitrary menstrual cycle in women with unexplained infertility and male infertility, and to determine the predictive value for long-term possibility of live birth.

METHODS

In this cross-sectional study, with 71 infertile women with diagnosis unexplained infertility and male infertility, blood samples were obtained during the proliferative and secretory phases of an arbitrary menstrual cycle. Serum concentrations of FSH, LH, AMH, inhibin B, estradiol, progesterone, PRL and TSH were determined. The predictive value of ovulation and hormonal analysis was determined by identifying the proportion of women with at least one live birth. Mann Whitney U test, chi2 test and Spearman's correlation were used for statistical analysis. A value of p < 0.05 was considered statistically significant.

RESULTS

There were no differences in hormone values and live birth rates between women with unexplained infertility and male infertility. The best sole predictors of live birth were age of the women, followed by ovulatory cycle, defined as serum progesterone concentration of greater than or equal to 32 nmol/L, and a serum TSH concentration of less than or equal to 2.5 mIU/L. Combining the age with the ovulatory cycle and serum TSH less than or equal to 2.5 mIU/L or serum AMH greater than or equal to 10 pmol/L the predictive value was close to 90%.

CONCLUSIONS

Age in combination with the presence of an ovulatory cycle and serum TSH or serum AMH is predictive for long-term live birth. The advantage of serum AMH compared with serum TSH is the very little variation throughout the menstrual cycle, which makes it a useful tool in infertility diagnosis.

Effect of Carissa opaca leaves extract on lipid peroxidation, antioxidant activity and reproductive hormones in male rats

BACKGROUND

Carissa opaca leaves are traditionally used in the treatment of male dysfunction and hormonal disorder as well as in oxidative stress in Pakistan and Asia. The present study was designed to assess the protective effects of methanolic extract of Carissa opaca leaves (MLC) on carbon tetrachloride (CCl4)-induced reproductive stress in male rats and bioactive constituents responsible for the activity.

METHODS

CCl4 was induced in 42 male rats for eight weeks and checked the protective efficacy of methanolic extract of Carissa opaca leaves at various hormonal imbalances, alteration of antioxidant enzymes, DNA fragmentation levels and lipid peroxidation caused testicular fibrosis in testis while High performance Liquid Chromatography (HPLC) was used for detection of bioactive components.

RESULTS

HPLC characterization revealed the presence of isoquercitin, hyperoside, vitexin, myricetin and kaempherol. CCl4 caused significant alteration in the secretion of reproductive hormones. Activity of antioxidant enzymes viz; catalase, superoxide dimutase and phase II metabolizing enzymes including glutathione peroxidase, glutathione reductase and reduced glutathione was decreased while DNA fragmentation, hydrogen per oxide contents and thiobarbituric acid reactive substances (TBARS) were increased with CCl4 treatment. Co-administration of 100 mg/kg and 200 mg/kg b.w. MLC effectively ameliorated the alterations in the biochemical markers; hormonal and molecular levels.

CONCLUSION

Protective effects of methanolic extract of Carissa opaca against CCl4-induced antioxidant and hormonal dysfunction which might be due to bioactive compound present in extract.

A common polymorphic allele of the LH beta-subunit gene is associated with higher exogenous FSH consumption during controlled ovarian stimulation for assisted reproductive technology

BACKGROUND

V-betaLH is a common genetic variant of LH caused by two polymorphic base changes in the beta subunit gene, altering the amino acid sequence (Trp8Arg and Ile15Thr). In a previous-preliminary trial performed in women undergoing IVF, it was demonstrated that carriers of v-betaLH show sub-optimal ovarian response to a standard long GnRH-agonist down -regulation protocol when stimulated with pure recombinant FSH (r-hFSH). The aim of this study was to confirm the hypothesis that women with v-betaLH display hypo-sensitivity to exogenous FSH in a larger IVF population and to explore the frequency of this variant in a Danish female population.

METHODS

In the present study, the effect of v-betaLH was retrospectively investigated in a larger series of women undergoing controlled ovarian stimulation (COS) and, for the first time, in a Danish IVF population. A total of 220 normogonadotrophic women following a long GnRH-agonist down-regulation protocol received an individualized dose of r-hFSH (100 IU and 375 IU s.c. daily) according to antral follicle count, baseline FSH, body mass index and age. The LH genotype was assessed in all patients by immunofluorometric assay.

RESULTS

V-betaLH was present in 11% of patients, whereas the allelic frequency was 12%. The study population was divided into two groups according to their LH genotype. Group A consisted of 196 wt/wt women. Group B included 24 individuals with v-betaLH (21 heterozygous and 3 homozygous). No statistically significant differences in the mean number of oocytes retrieved, fertilization rate and pregnancy rate per cycle were observed between groups. However, Group B received a significantly higher cumulative-dose of r-hFSH than Group A (2435.86 +/- 932.8 IU versus 1959.8 +/- 736.45 p = 0.048). When one-way ANOVA in a within design was applied, the LH genotype had a statistically significant effect (p < 0.01) on the cumulative dose of r-hFSH, showing a progressive increase from wt/wt (1959.8 +/- 736.45 IU) to v-betaLH hetero- (2267.5 +/- 824.3) and homozygotic women (3558.3 +/- 970.9).

CONCLUSIONS

These results confirm that carriers exhibit hypo-sensitivity to exogenous FSH during COS, documenting that the frequency of v-betaLH in Denmark is similar to a number of European countries.

The role for runt related transcription factor 2 (RUNX2) as a transcriptional repressor in luteinizing granulosa cells

Transcription factors induced by the LH surge play a vital role in reprogramming the gene expression in periovulatory follicles. The present study investigated the role of RUNX2 transcription factor in regulating the expression of Runx1, Ptgs2, and Tnfaip6 using cultured granulosa cells isolated from PMSG-primed immature rats. hCG or forskolin+PMA induced the transient increase in Runx1, Ptgs2, and Tnfaip6 expression, while the expression of Runx2 continued to increase until 48 h. The knockdown of the agonist-stimulated Runx2 expression increased Runx1, Ptgs2, and Tnfaip6 expression and PGE(2) levels in luteinizing granulosa cells. Conversely, the over-expression of RUNX2 inhibited the expression of these genes and PGE(2) levels. The mutation of RUNX binding motifs in the Runx1 promoter enhanced transcriptional activity of the Runx1 promoter. The knockdown and overexpression of Runx2 increased and decreased Runx1 promoter activity, respectively. ChIP assays revealed the binding of RUNX2 in the Runx1 and Ptgs2 promoters. Together, these novel findings provide support for the role of RUNX2 in down-regulation of Runx1, Ptgs2, and Tnfaip6 during the late ovulatory period to support proper ovulation and/or luteinization.

Steroidogenic and maturation-inducing potency of native gonadotropic hormones in female chub mackerel, Scomber japonicus

BACKGROUND

The gonadotropins (GtHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are produced in the pituitary gland and regulates gametogenesis through production of gonadal steroids. However, respective roles of two GtHs in the teleosts are still incompletely characterized due to technical difficulties in the purification of native GtHs.

METHODS

Native FSH and LH were purified from the pituitaries of adult chub mackerel, Scomber japonicus by anion-exchange chromatography and immunoblotting using specific antisera. The steroidogenic potency of the intact chub mackerel FSH (cmFSH) and LH (cmLH) were evaluated in mid- and late-vitellogenic stage follicles by measuring the level of gonadal steroids, estradiol-17beta (Ε2) and 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P). In addition, we evaluated the maturation-inducing potency of the GtHs on same stage follicles.

RESULTS

Both cmFSH and cmLH significantly stimulated E2 production in mid-vitellogenic stage follicles. In contrast, only LH significantly stimulated the production of 17,20beta-P in late-vitellogenic stage follicles. Similarly, cmLH induced final oocyte maturation (FOM) in late-vitellogenic stage follicles.

CONCLUSIONS

Present results indicate that both FSH and LH may regulate vitellogenic processes, whereas only LH initiates FOM in chub mackerel.

Differential response to sustained stimulation by hCG & LH on goat ovarian granulosa cells

BACKGROUND & OBJECTIVES

Chapekar established a model of ovarian tumourigenesis in mice by splenic transplantation of ovaries, resulting in sustained luteinizing hormone (LH) levels because of absence of feedback inhibition. There is increasing evidence of the differential response to LH or hCG under various experimental conditions. The effect of sustained hormonal stimulation in long term cultures is sparsely investigated. The study is aimed to determine the role of hCG and LH stress on caprine ovarian granulosa cells and their downstream signaling in short and long term cultures.

METHODS

To study the response of hCG and LH stress and downstream signaling, short term cultures were set up by exposing goat ovarian granulosa cells in primary cultures to hCG and LH stress (levels beyond their physiological doses) for 5 days (P0). Cells were sub-cultured at sixth day and subjected to prolonged LH/ hCG stress for two weeks in passage 1(P1) (long term cultures). Downstream cell signaling molecules were assessed. Intracellular cAMP was estimated by ELISA. For PKA and PKC, activity assays were performed. pERK protein expressions in short term cultures were assessed by Western blot and flowcytometry; in long term cultures, pERK expression was analyzed by flowcytometry.

RESULTS

Differential effects on cell proliferation were observed in long term cultures, where the untreated and hCG exposed cells showed markedly reduced cell proliferation after second week of exposure while LH treated cells continued to proliferate. Different levels of cAMP, PKA, PKC and phosphorylated ERK1/2 were observed on short term and long term LH stimulation. On sustained hormonal stimulation, cAMP levels were significantly (P<0.05) higher in hCG treated cultures as compared to controls and LH treated cultures. LH led to maximal elevation of ERK in long term cultures.

INTERPRETATION & CONCLUSIONS

As pERK1/2 promotes cellular proliferation, activation of ERK1/2 in LH treated cultures may be responsible for sustained growth. Prolonged LH treatment promoted growth and proliferation in caprine ovarian granulosa cells whereas prolonged exposure to hCG led to elevated levels of cAMP and decreased the rate of proliferation. Defining the signals and second messengers that act as survival or apoptotic mediators may help in elucidation of the mechanisms controlling proliferation or programmed cell death in granulosa cells.

Aryl hydrocarbon receptor activation in lactotropes and gonadotropes interferes with estradiol-dependent and -independent preprolactin, glycoprotein alpha and luteinizing hormone beta gene expression

Arylhydrocarbon receptor (Ahr) activation by 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD) interferes with female reproductive functions, but there is little information on the specific targets of TCDD in the hypothalamic-pituitary-gonadal (HPG) axis. In these studies, we found that TCDD upregulated known AhR target genes, cytochrome p450 1a1 (Cyp1a1), Cyp1a2 and Cyp1b1 in the rat pituitary gland. Moreover, 75% of pituitary lactotropes and 45% of gonadotropes contained Ahr mRNA, and most Ahr-containing cells were estrogen receptor 1 (Esr1)-positive. TCDD abrogated estradiol (E(2))-induced prolactin (Prl) expression in vivo and in vitro; conversely, E(2) blocked TCDD upregulation of luteinizing hormone beta (Lhb) and glycoprotein hormone alpha polypeptide (Cga) expression. TCDD had no effect on levels of Ahr mRNA, but upregulated Esr1 mRNA. E(2) independently repressed Ahr and Esr1 expression and blocked TCDD upregulation of Esr1. Thus, complex interactions between Ahr and Esr alter Prl and luteinizing hormone (LH) synthesis by direct actions in lactotropes and gonadotropes. These findings provide important insights into how TCDD disrupts female reproductive functions.

Intraovarian expression of GnRH-1 and gonadotropin mRNA and protein levels in Siberian hamsters during the estrus cycle and photoperiod induced regression/recrudescence

The hypothalamic-pituitary-gonadal (HPG) axis is the key reproductive regulator in vertebrates. While gonadotropin releasing hormone (GnRH), follicle stimulating (FSH), and luteinizing (LH) hormones are primarily produced in the hypothalamus and pituitary, they can be synthesized in the gonads, suggesting an intraovarian GnRH-gonadotropin axis. Because these hormones are critical for follicle maturation and steroidogenesis, we hypothesized that this intraovarian axis may be important in photoperiod-induced ovarian regression/recrudescence in seasonal breeders. Thus, we investigated GnRH-1 and gonadotropin mRNA and protein expression in Siberian hamster ovaries during (1) the estrous cycle; where ovaries from cycling long day hamsters (LD;16L:8D) were collected at proestrus, estrus, diestrus I, and diestrus II and (2) during photoperiod induced regression/recrudescence; where ovaries were collected from hamsters exposed to 14 weeks of LD, short days (SD;8L:16D), or 8 weeks post-transfer to LD after 14 weeks SD (PT). GnRH-1, LHβ, FSHβ, and common α subunit mRNA expression was observed in cycling ovaries. GnRH-1 expression peaked at diestrus I compared to other stages (p < 0.05). FSHβ and LHβ mRNA levels peaked at proestrus and diestrus I (p < 0.05), with no change in the α subunit across the cycle (p > 0.05). SD exposure decreased ovarian mass and plasma estradiol concentrations (p<0.05) and increased GnRH-1, LHβ, FSHβ, and α subunit mRNA expression as compared to LD and, except for LH, compared to PT (p < 0.05). GnRH and gonadotropin protein was also dynamically expressed across the estrous cycle and photoperiod exposure. The presence of cycling intraovarian GnRH-1 and gonadotropin mRNA suggests that these hormones may be locally involved in ovarian maintenance during SD regression and/or could potentially serve to prime ovaries for rapid recrudescence.

Forebrain projections of arcuate neurokinin B neurons demonstrated by anterograde tract-tracing and monosodium glutamate lesions in the rat

Neurokinin B (NKB) and kisspeptin receptor signaling are essential components of the reproductive axis. A population of neurons resides within the arcuate nucleus of the rat that expresses NKB, kisspeptin, dynorphin, NK3 receptors and estrogen receptor alpha (ERalpha). Here we investigate the projections of these neurons using NKB-immunocytochemistry as a marker. First, the loss of NKB-immunoreactive (ir) somata and fibers was characterized after ablation of the arcuate nucleus by neonatal injections of monosodium glutamate. Second, biotinylated dextran amine was injected into the arcuate nucleus and anterogradely labeled NKB-ir fibers were identified using dual-labeled immunofluorescence. Four major projection pathways are described: (1) local projections within the arcuate nucleus bilaterally, (2) projections to the median eminence including the lateral palisade zone, (3) projections to a periventricular pathway extending rostrally to multiple hypothalamic nuclei, the septal region and BNST and dorsally to the dorsomedial nucleus and (4) Projections to a ventral hypothalamic tract to the lateral hypothalamus and medial forebrain bundle. The diverse projections provide evidence that NKB/kisspeptin/dynorphin neurons could integrate the reproductive axis with multiple homeostatic, behavioral and neuroendocrine processes. Interestingly, anterograde tract-tracing revealed NKB-ir axons originating from arcuate neurons terminating on other NKB-ir somata within the arcuate nucleus. Combined with previous studies, these experiments reveal a bilateral interconnected network of sex-steroid responsive neurons in the arcuate nucleus of the rat that express NKB, kisspeptin, dynorphin, NK3 receptors and ERalpha and project to GnRH terminals in the median eminence. This circuitry provides a mechanism for bilateral synchronization of arcuate NKB/kisspeptin/dynorphin neurons to modulate the pulsatile secretion of GnRH.

GPR30 differentially regulates short latency responses of luteinising hormone and prolactin secretion to oestradiol

Rapid, nongenomic actions of 17beta-oestradiol (E(2)) on hypothalamic neurones that may be relevant to reproductive function were described decades ago. The orphan G protein-coupled receptor, GPR30, was recently shown to bind oestrogens and to trigger rapid signalling in vitro, and is expressed in several rat and human brain regions, including the hypothalamus. We used two complementary approaches to investigate the role of GPR30 in hypothalamic responses to E(2) that are relevant to reproductive physiology. Serial blood sampling after the acute administration of the selective GPR30 agonist G1 was used to assess the role of GPR30 in short latency negative-feedback inhibition of luteinising hormone (LH) secretion and facilitation of prolactin secretion in ovariohysterectomised female rats. In vivo RNA interference (RNAi), mediated by adeno-associated virus-expressing small hairpin RNA (shRNA) infused into the mediobasal hypothalamus, was used to study the effects of GPR30 knockdown on these rapid responses to E(2). Longer-term actions of E(2) on female sexual behaviour (lordosis) were also examined in female rats subjected to in vivo RNAi. Administration of E(2) or G1 triggered a short latency surge of prolactin secretion, and animals subjected to GPR30 RNAi showed significantly less E(2)-dependent prolactin release than animals receiving control virus. G1 did not mimic E(2) negative-feedback inhibition of LH secretion, and GPR30 RNAi did not interfere with E(2) suppression of LH or facilitation of lordosis behaviour. These findings suggest that activation of GPR30 promotes short latency prolactin secretion but does not mediate E(2) negative-feedback inhibition of LH secretion or E(2) facilitation of female reproductive behaviour.

Retinol-binding protein levels are increased in association with gonadotropin levels in healthy women

Recent studies have demonstrated an association between retinol-binding protein (RBP4) and insulin resistance. Retinol-binding protein is decreased in women and elevated in polycystic ovary syndrome. However, prior studies have not investigated the relationship between RBP4, gonadal steroids, and gonadotropins in healthy women. The aim of this study was to determine the RBP4 levels in a cohort of healthy women with a range of body mass indices and glucose tolerances to investigate the relationship between RBP4, gonadotropin levels, and menopausal status. Serum RBP4 levels were measured by enzyme-linked immunosorbent assay and quantitative Western blot in 88 healthy women (aged 24-59 years) from the general community in a cross-sectional study. Retinol-binding protein was higher in postmenopausal compared with premenopausal women (26.1 +/- 2.1 vs 19.3 +/- 0.5 mug/mL, P = .001). In univariate analysis, RBP4 was associated with follicle-stimulating hormone (r = 0.37, P = .0004), luteinizing hormone (r = 0.3, P = .005), and sex hormone-binding globulin (r = -0.24, P = .03) and trended to significance with estradiol (P = .09) but not with free testosterone or dehydroepiandrosterone sulfate. Retinol-binding protein was also associated with insulin at 2 hours during an oral glucose tolerance test (r = 0.24, P = .03) and the area under the curve for insulin during the oral glucose tolerance test (r = 0.26, P = .02). In multivariate regression modeling, both follicle-stimulating hormone (P = .03) and luteinizing hormone (P = .04) remained significantly associated with RBP4 after controlling for estradiol, sex hormone-binding globulin, insulin area under the curve, cholesterol, triglycerides, waist-to-hip ratio, and tumor necrosis factor alpha. Retinol-binding protein was not associated with inflammatory markers or with carotid intima-media thickness. Therefore, RBP4 is higher in postmenopausal women and is associated with gonadotropin concentrations in healthy women.

Role of seminiferous tubular development in determining the FSH versus LH responsiveness to GnRH in early sexual maturation

BACKGROUND

The onset of sexual maturation at puberty is a unique developmental period from a neuroendocrine perspective in that it is characterized by enhanced FSH secretion and FSH responsiveness to exogenous GnRH (vs. LH) from the gonadotrope, yet the mechanism of these dynamics remains unclear. This study aimed to elucidate this phenomenon using a human disease model of GnRH deficiency (idiopathic hypogonadotropic hypogonadism, IHH) in which GnRH input can be experimentally controlled.

METHODS

25 GnRH-deficient men were selected for study based upon their baseline testicular volumes (TV) and serum inhibin B (I(B)) levels to represent a spectrum of pubertal/testicular development. Subjects underwent: (i) a 12-hour overnight neuroendocrine evaluation for hormonal profiling and determination of endogenous LH secretion pattern, and (ii) a 7-day exposure to a physiologic regimen of exogenous pulsatile GnRH (25 ng/kg every 2 h). Daily measurements of serum testosterone (T) and I(B) levels were made and a 2-hour window of frequent blood sampling was monitored to measure LH and FSH following a single i.v. GnRH bolus (25 ng/kg). All subjects were screened for known loci underlying GnRH deficiency and the response to GnRH was tracked according to genotype.

RESULTS

Among the entire cohort, no changes were noted in serum T or I(B) during the 7 days, thus keeping gonadal feedback relatively constant. However, serum LH and FSH levels increased significantly (p < 0.0001) in the entire cohort. When analyzed by degree of pubertal/testicular development, men with no evidence of prior spontaneous pubertal development (TV <or=3 ml, Group I) showed sharp increases in serum FSH compared to men with some prior evidence of partial puberty (TV >3 ml, Group II, p < 0.0001). Group I exhibited a decreased LH response to GnRH on day 2 compared to day 1 (p < 0.01), which did not recover until day 5 (1-4 vs. 5-7 days, p < 0.0001). Group II displayed robust and equivalent LH responses to GnRH throughout the 7-day study. Genetic studies identified 8 mutations in 4 different loci (DAX1, KAL1, GNRHR, and FGFR1) in this cohort.

CONCLUSIONS

GnRH-deficient men undergoing GnRH-induced sexual maturation display an inverse relationship between FSH responsiveness to GnRH and baseline testicular size and I(B) levels. This observation implies that increasing seminiferous tubule maturity represents the major constraint on FSH responsiveness to GnRH in early puberty. In contrast, LH responsiveness to GnRH correlates directly with duration of GnRH exposure. Attenuated pituitary gonadotropin responses were noted in subjects harboring DAX1 mutations, consistent with known pituitary defects.

Reflexive testosterone release: a model system for studying the nongenomic effects of testosterone upon male behavior

Male mammals of many species exhibit reflexive testosterone release in mating situations. In house mice (Mus musculus), the dramatic robustness of such release, occurring primarily in response to a novel female, suggests some function. The resulting testosterone elevations typically peak during copulatory behavior and may serve to activate transitory motivational and physiological responses that facilitate reproduction. However, such a function requires that testosterone be working through either nongenomic, or very quick genomic, mechanisms. The first part of the review describes reflexive sex hormone release in house mice. The second part summarizes research implicating testosterone's fast actions in affecting anxiety, reward, learning, analgesia, and penile reflexes in rodents, all of which could optimize male mating success. The review concludes with a speculative model of how spontaneous and reflexive hormone release might interact to regulate reproductive behavior and why mice appear to be an ideal species for examining testosterone's quick effects.

Brain aromatase: roles in reproduction and neuroprotection

It is well established that aromatization constitutes an essential part of testosterone's signaling pathway in brain and that estrogen metabolites, often together with testosterone, organize and activate masculine neural circuits. This paper summarizes the current understanding regarding the distribution, regulation and function of brain aromatase in mammals. Data from our laboratory are presented that highlight the important function of aromatase in the regulation of androgen feedback sensitivity in non-human primates and the possible role that aromatase plays in determining the brain structure and sexual partner preferences of rams. In addition, new data is presented indicating that the capacity for aromatization in cortical astrocytes is associated with cell survival and may be important for neuroprotection. It is anticipated that a better appreciation of the physiological and pathophysiological functions of aromatase will lead to important clinical insights.

Obesity and sex steroid changes across puberty: evidence for marked hyperandrogenemia in pre- and early pubertal obese girls

CONTEXT

Peripubertal obesity is associated with abnormal sex steroid concentrations, but the timing of onset and degree of these abnormalities remain unclear.

OBJECTIVE

The objective of the study was to assess the degree of hyperandrogenemia across puberty in obese girls and assess overnight sex steroid changes in Tanner stage 1-3 girls.

DESIGN

This was a cross-sectional analysis.

SETTING

The study was conducted at general clinical research centers.

SUBJECTS

Thirty normal-weight (body mass index for age < 85%) and 74 obese (body mass index for age >or= 95%) peripubertal girls.

INTERVENTION

Blood samples (circa 0500-0700 h) were taken while fasting. Samples from the preceding evening (circa 2300 h) were obtained in 23 Tanner 1-3 girls.

MAIN OUTCOME MEASURES

Hormone concentrations stratified by Tanner stage were measured.

RESULTS

Compared with normal-weight girls, mean free testosterone (T) was elevated 2- to 9-fold across puberty in obese girls, whereas fasting insulin was 3-fold elevated in obese Tanner 1-3 girls (P < 0.05). Mean LH was lower in obese Tanner 1 and 2 girls (P < 0.05) but not in more mature girls. In a subgroup of normal-weight Tanner 1-3 girls (n = 17), mean progesterone (P) and T increased overnight 2.3- and 2.4-fold, respectively (P <or= 0.001). In obese Tanner 1-3 girls (n = 6), evening P and T were elevated, and both tended to increase overnight [mean 1.4- and 1.6-fold, respectively (P = 0.06)].

CONCLUSIONS

Peripubertal obesity is associated with hyperandrogenemia and hyperinsulinemia throughout puberty, being especially marked shortly before and during early puberty. P and T concentrations in normal-weight Tanner 1-3 girls increase overnight, with similar but less evident changes in obese girls.

Reproductive hormone levels in men exposed to persistent organohalogen pollutants: a study of inuit and three European cohorts

OBJECTIVE

Persistent organohalogen pollutant (POP) exposure may have a negative impact on reproductive function. The objective of this study was to assess the impact of POP exposure on the male hypothalamo-pituitary-gonadal axis.

PARTICIPANTS

Participants included 184 Swedish fishermen and spouses of pregnant women from Greenland (n = 258), Warsaw, Poland (n = 113) , and Kharkiv, Ukraine (n = 194).

EVALUATIONS/MEASUREMENTS

Serum levels of 2,2,4,4,5,5-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p -DDE) were determined in the four populations, showing different exposure patterns: Swedish fishermen, high CB-153/low p,p -DDE; Greenland, high CB-153/high p,p -DDE; Warsaw, low CB-153/moderate p,p -DDE; Kharkiv, low CB-153/high p,p -DDE. Serum was also analyzed for testosterone, estradiol, sex hormone-binding globulin (SHBG) , inhibin B, luteinizing hormone (LH) , and follicle-stimulating hormone (FSH) . Free testosterone levels were calculated based on testosterone and SHBG.

RESULTS

We found significant center-to-center variations in the associations between exposure and the outcomes. The most pronounced effects were observed in Kharkiv, where statistically significant positive associations were found between the levels of both CB-153 and p,p -DDE and SHBG, as well as LH. In Greenland, there was a positive association between CB-153 exposure and LH. In the pooled data set from all four centers, there was positive association between p,p -DDE and FSH levels [beta = 1.1 IU/L; 95% confidence interval (CI), 1.0-1.1 IU/L]. The association between CB-153 levels and SHBG was of borderline statistical significance (beta = 0.90 nmol/L; 95% CI, -0.04 to 1.9 nmol/L).

CONCLUSIONS

Gonadotropin levels and SHBG seem to be affected by POP exposure, but the pattern of endocrine response is the subject of considerable geographic variation.

Cellular and hormonal disruption of fetal testis development in sheep reared on pasture treated with sewage sludge

The purpose of this study was to evaluate whether experimental exposure of pregnant sheep to a mixture of environmental chemicals added to pasture as sewage sludge (n = 9 treated animals) exerted effects on fetal testis development or function; application of sewage sludge was undertaken so as to maximize exposure of the ewes to its contents. Control ewes (n = 9) were reared on pasture treated with an equivalent amount of inorganic nitrogenous fertilizer. Treatment had no effect on body weight of ewes, but it reduced body weight by 12-15% in male (n = 12) and female (n = 8) fetuses on gestation day 110. In treated male fetuses (n = 11), testis weight was significantly reduced (32%), as were the numbers of Sertoli cells (34% reduction), Leydig cells (37% reduction), and gonocytes (44% reduction), compared with control fetuses (n = 8). Fetal blood levels of testosterone and inhibin A were also reduced (36% and 38%, respectively) in treated compared with control fetuses, whereas blood levels of luteinizing hormone and follicle-stimulating hormone were unchanged. Based on immunoexpression of anti-Müllerian hormone, cytochrome P450 side chain cleavage enzyme, and Leydig cell cytoplasmic volume, we conclude that the hormone changes in treated male fetuses probably result from the reduction in somatic cell numbers. This reduction could result from fetal growth restriction in male fetuses and/or from the lowered testosterone action; reduced immunoexpression of alpha-smooth muscle actin in peritubular cells and of androgen receptor in testes of treated animals supports the latter possibility. These findings indicate that exposure of the developing male sheep fetus to real-world mixtures of environmental chemicals can result in major attenuation of testicular development and hormonal function, which may have consequences in adulthood.

Pesticide exposure alters follicle-stimulating hormone levels in Mexican agricultural workers

Organophosphorous pesticides (OPs) are suspected of altering reproductive function by reducing brain acetylcholinesterase activity and monoamine levels, thus impairing hypothalamic and/or pituitary endocrine functions and gonadal processes. Our objective was to evaluate in a longitudinal study the association between OP exposure and serum levels of pituitary and sex hormones. Urinary OP metabolite levels were measured by gas-liquid chromatography, and serum pituitary and sex hormone levels by enzymatic immunoassay and radioimmunoassay in 64 men. A total of 147 urine and blood samples were analyzed for each parameter. More than 80% of the participants had at least one OP metabolite in their urine samples. The most frequent metabolite found was diethylthiophosphate (DETP; 55%), followed by diethylphosphate (DEP; 46%), dimethylthiophosphate (DMTP; 32%), and dimethyldithiophosphate (DMDTP; 31%). However, the metabolites detected at higher concentrations were DMTP, DEP, DMDTP, and dimethylphosphate. There was a high proportion of individuals with follicle-stimulating hormone (FSH) concentrations outside the range of normality (48%). The average FSH serum levels were higher during the heavy pesticide spraying season. However, a multivariate analysis of data collected in all periods showed that serum FSH levels were negatively associated with urinary concentrations of both DMTP and DMDTP, whereas luteinizing hormone (LH) was negatively associated with DMTP. We observed no significant associations between estradiol or testosterone serum levels with OP metabolites. The hormonal disruption in agricultural workers presented here, together with results from experimental animal studies, suggests that OP exposure disrupts the hypothalamic-pituitary endocrine function and also indicates that FSH and LH are the hormones most affected.

Differentiation of adult-type Leydig cells occurs in gonadotrophin-deficient mice

During mammalian testis development distinct generations of fetal and adult Leydig cells arise. Luteinising hormone (LH) is required for normal adult Leydig cell function and for the establishment of normal adult Leydig cell number but its role in the process of adult Leydig cell differentiation has remained uncertain. In this study we have examined adult Leydig cell differentiation in gonadotrophin-releasing hormone (GnRH)-null mice which are deficient in circulating gonadotrophins. Adult Leydig cell differentiation was assessed by measuring expression of mRNA species encoding four specific markers of adult Leydig cell differentiation in the mouse. Each of these markers (3beta-hydroxysteroid dehydrogenase type VI (3betaHSD VI), 17beta-hydroxysteroid dehydrogenase type III (17betaHSD III), prostaglandin D (PGD)-synthetase and oestrogen sulphotransferase (EST)) is expressed only in the adult Leydig cell lineage in the normal adult animal. Real-time PCR studies showed that all four markers are expressed in adult GnRH-null mice. Localisation of 3betaHSD VI and PGD-synthetase expression by in situ hybridisation confirmed that these genes are expressed in the interstitial tissue of the GnRH-null mouse. Treatment of animals with human chorionic gonadotrophin increased expression of 3betaHSD VI and 17betaHSD III within 12 hours further indicating that differentiated, but unstimulated cells already exist in the GnRH-null mouse. Thus, while previous studies have shown that LH is required for adult Leydig cell proliferation and activity, results from the present study show that adult Leydig cell differentiation will take place in animals deficient in LH.

The effect of exogenous luteinizing hormone (LH) on oocyte viability: evidence from a comparative study using recombinant human follicle-stimulating hormone (FSH) alone or in combination with recombinant LH for ovarian stimulation in pituitary-suppressed women undergoing assisted reproduction

PURPOSE

The purpose of this prospective, randomized study was to compare ovarian response and oocyte and embryo yields in women undergoing ovulation induction for IVF/ICSI using recombinant human FSH (rhFSH) alone or in combination with recombinant human LH (rhLH).

METHODS

Patients were randomized to receive rhFSH alone (group F; n = 13) or rhFSH + rhLH (group L; n = 15). rhFSH was administered according to a step-down protocol; patients assigned to group L received rhLH at a fixed dose of 75 IU (1 ampoule) throughout the treatment period.

RESULTS

The total dose of rhFSH, number of growing follicles, and serum concentrations of estradiol (E2) on the day of hCG administration were similar in both treatment groups. However, the percentage of metaphase II oocytes and fertilization rate were significantly higher in group F than in group L. The lower fertilization rates associated with rhLH were also seen in a subgroup of patients from group L who had undergone a previous ART cycle stimulated with FSH only and thus acted as their own controls. However, when in vitro fertilization (IVF) and intracytoplasmic sperm injection cycles were considered separately, differences in fertilization rates were statistically significant only for oocytes treated by conventional IVF.

CONCLUSIONS

This study shows that the addition of recombinant LH to recombinant FSH in pituitary-suppressed women undergoing ART does not improve the ovarian response and even may have a negative impact on oocyte maturation and fertilization.

Effect of alcohol on the proestrous surge of luteinizing hormone (LH) and the activation of LH-releasing hormone (LHRH) neurons in the female rat

Reproduction is adversely affected by alcohol abuse in humans and laboratory animals. In rats, alcohol exposure suppresses both luteinizing hormone (LH) and sex steroid secretion, although consensus is lacking as to which level of the hypothalamic-pituitary-gonadal (HPG) axis is primarily affected. We tested the hypothesis that acute alcohol treatment inhibits the HPG axis by blunting release of LH-releasing hormone (LHRH) in female rats, by examining the effect of this drug on the central reproductive endocrine event; i.e., the proestrous surge of gonadotropins, which triggers ovulation. In a first series of experiments, we injected alcohol at 8 A.M. and 12 P.M. on proestrus and measured plasma levels of LH, estradiol (E2), and progesterone during the afternoons of proestrus and estrus. Alcohol administration blocked the proestrous surge of LH and ovulation. In subsequent experiments, alcohol inhibited the surge of LHRH (measured by push-pull cannulation) and LHRH neuronal activation (measured by Fos labeling in LHRH neurons). Because alcohol also decreased E2 levels, we reasoned that it might have prevented positive feedback; however, alcohol retained its ability to inhibit the LH surge evoked by E2 implantation in ovariectomized females, disproving this hypothesis. Additionally, alcohol does not act via increased corticosteroid secretion, because alcohol also blocked the proestrous surge in adrenalectomized females. Last, exogenous administration of LHRH to alcohol-blocked animals evoked LH secretion and ovulation, indicating that pituitary and/or ovarian function could be restored by mimicking the hypothalamic signal. Collectively, these data indicate that in female rats, alcohol inhibits the gonadotropin surge primarily by decreasing LHRH secretion.

Heterologous radioimmunoassay for llama and alpaca luteinizing hormone with a monoclonal antibody, an equine standard and a human tracer

A radioimmunoassay for llama and alpaca LH was developed using a human I125LH tracer from a commercial kit, equine LH diluted in human LH free serum as standard, and a monoclonal antibody (518B7) specific for LH but with low species specificity. A 60-min delay in the addition of the tracer and overnight incubation gave a sensitivity of 0.8 microgram L-1. The intra-assay coefficient of variation was 37% at 1 microgram L-1, declined to 15% at 4 micrograms L-1 and was below 6% for concentrations up to 32 micrograms L-1. The inter-assay coefficients of variation for 3 control samples were 20% (2.8 micrograms L-1), 16% (7.1 micrograms L-1) and 9.8% (19 micrograms L-1). In an attempt to increase sensitivity, all tubes were preincubated for 4 h at room temperature before adding the tracer, and the sample volume was increased from 50 microL to 100 microL (in the standard curve the increased volume was compensated for by human LH free serum). With this protocol, the assay sensitivity was 0.5 microgram L-1. The assay was validated clinically and demonstrated increased concentrations of LH after mating in llamas and alpacas. Furthermore, the assay was used to monitor LH responses to a single dose of GnRH in llamas (adult males and females at different ages).

Effects of oestrogenic silage on some clinical and endocrinological parameters in ovariectomized heifers

The influence of phytoestrogens was studied in 3 ovariectomized Swedish Friesian heifers fed 20 kg of 100% red clover silage per heifer/day for 14 days. Behaviour, reproductive organs and pituitary response to exogenous gonadotropin-releasing hormone (GnRH) injections were monitored. Clinical effects like oedema and mucous discharge in the vulva, presence of milky fluid in the mammae and increases in teat size and the cross-sectional distance of the uterus were observed in heifers fed red clover silage. Fluid accumulation in the uterus, visualized by means of ultrasonography, had still not disappeared 30 days after the red clover silage had been completely withdrawn. Red clover silage appeared to reduce the magnitude and duration of the pituitary response to GnRH injections.

Radioimmunoassay of bovine, ovine and porcine luteinizing hormone with a monoclonal antibody and a human tracer

A radioimmunoassay for bovine (bLH), ovine (oLH) and porcine (pLH) luteinizing hormone was developed using a human 125ILH tracer from a commercial kit and a monoclonal antibody (518B7) specific for LH but with low species specificity. Standard curves demonstrated similar binding kinetics when bLH, oLH and pLH were incubated with tracer and antibody for 2 h at room temperature. A 30-min delay in the addition of the tracer gave sufficient sensitivity when analysing pLH. Separation of antibody-bound LH from free hormone was achieved by using second antibody-coated micro Sepharose beads. The assay was validated and the performance compared with that of an RIA currently in use for determination of bLH and oLH (coefficient of correlation: 0.99 and 0.98). Regardless of the standards used, intra-assay coefficients of variation were < 10% for LH concentrations exceeding 1 microgram/L. The inter-assay coefficients of variation were < 15%. The assay was used for clinical evaluation demonstrating the pre-ovulatory LH surge in two cyclic cows, LH pulsatility in an oophorectomized ewe and LH response to GnRH injection in a boar.

Hormonal interrelationships in postpartum suckled dairy cows

Three cross-bred cows calved in March and April and were followed until day 62 after parturition. Each animal was suckled by 2 calves ad libitum. All calves were removed from the cows on day 55 after parturition. Blood was collected 3 times per day from the jugular vein by venipuncture. On 4 occasions after parturition--i.e. days 7-8, 21-22, 35-36 and 49-50, the cows were bled through a jugular venous catheter every 30 min during the 24 h. The plasma samples were analyzed for the content of 15-keto-13,14-dihydro-PGF2 alpha (main PGF2 alpha metabolite), LH, prolactin, cortisol and progesterone by radioimmunoassay methods. The concentration of PGF2 alpha increased from 280 to 730 pmol/l within the last 4 days before parturition. The highest geometric mean was 3106 pmol/l on the day of parturition. Thereafter a steady decrease of PGF2 alpha metabolite concentration was seen until day 21 when it reached plateau at 148 pmol/l. In all cows plasma LH concentrations increased significantly (P < 0.05) from about 1.6 micrograms/l on days 7-8 to 2.4 micrograms/l on days 21-22 post partum. The frequency of LH pulses showed no tendency to increase as the postpartum period progressed and averaged 6.5 pulses/24 h. Mean plasma LH concentrations increased from 2.1 micrograms/l 2 days before weaning to 3.2 micrograms/l 2 days after weaning (P < 0.05). LH peaks occurred less frequently in association with prolactin and cortisol peaks than in their absence. A partial positive correlation between PGF2 alpha metabolite and cortisol (r = 0.30) was found on days 7-8 post partum. Correlation between prolactin and cortisol on days 7-8 and 21-22 post partum was also positive (r = 0.20 and r = 0.27, respectively). There was a negative correlation between LH and cortisol on days 7-8 (r = -0.27) and days 49-50 (r = -0.21) post partum. The first and short progesterone increase observed after weaning was terminated in conjunction with PGF2 alpha metabolite peaks.

Effect of fractionated weaning on hormonal patterns and weaning to oestrus interval in primiparous sows

The effect of weaning the 4-5 heaviest piglets in the litter on day 33 of lactation and the remainder 2 days later (fractionated weaning) on plasma levels of prolactin, cortisol, oestradiol-17 beta (E2), progesterone (P4) and LH, as well as on the weaning to oestrus interval in primiparous sows was studied. Twelve crossbred sows were grouped into 6 pairs according to farrowing date and litter size. The litter of 1 sow in each pair (F) was weaned in 2 stages, and the other conventionally weaned at 35 days (C). Blood samples were collected via a permanent jugular vein catheter every 3 h from 9 a m to 9 p m daily throughout the experimental period, and intensively at 15 min intervals for 12 h on the day of first and final weaning and for 6 h on the day after each weaning. All sows were slaughtered following their first post-weaning oestrus and the reproductive organs were macroscopically examined. Lactational oestrus was not observed in any of the sows. Sows from 5 out of 6 pairs showed oestrus within 8 days of weaning and post-mortem examination showed normal ovulation. There was a tendency for the F sows to have a shorter weaning to oestrus interval, as compared with the C sows (5 of 6 pairs, 4.8 days v 5.6 days). The plasma levels of prolactin around weaning were not significantly different between the 2 groups. Within 6 h after final weaning, the prolactin concentrations decreased gradually from 7.6 and 8.7 to 1.6 and 1.7 microgram/l in the control and treatment groups, respectively. The plasma levels of cortisol, showing a diurnal rhythm (with the lowest level at 6 and/or 9 p m), did on no occasion differ between the 2 groups. On the day of final weaning, no diurnal rhythm was observed, with cortisol remaining high at 6 and 9 p m. The plasma levels of E2 and P4 were low until final weaning in both groups. After final weaning the E2 levels rose faster in the F sows than in the C sows, to 44.3 and 34.8 pmol/l, respectively, on day 2 (p less than 0.01). No significant differences in levels of plasma LH and the number of LH pulses were observed between the groups. After final weaning the average and base levels of LH and the number of LH pulse(s) increased significantly.

Effect of transportation and relocation in post-weaning anoestrous primiparous sows

The object of this investigation was to study the clinical and endocrine responses to transportation and relocation in 8 post-weaning anoestrous sows. They had been anoestrous for at least 24 days after weaning before transportation/relocation was performed. Laparoscopy, performed at the beginning of the experiment, revealed that the ovaries contained many follicles (less than or equal to 6 mm in diameter), but no corpora lutea. Blood samples, taken before and after transportation/relocation, showed that LH activity was low at the beginning of the experiment and increased after transportation/relocation in the majority of the sows. Peripheral plasma concentrations of of oestradiol-17 beta increased 1-4 days after transportation/relocation in 6 out of 8 sows which was followed by oestrus and ovulation. Progesterone concentrations were also below the practical detection limit until the end of oestrus. This study has demonstrated that a change in environment by transportation and relocation can induce oestrus by increasing the LH activity in post-weaning anoestrous sows.

Clinical, morphological and endocrinological studies in gilts with delayed puberty

Thirty-six gilts which had not shown oestrus at about 8 months of age or more were transported from the pig research station to the clinic, a journey of 12 km. The gilts were examined by laparoscopy and those which had only small follicles in the ovaries were catheterized and placed in pens, with sexually mature boars kept in adjacent pens. Oestrus detection was done twice daily and blood was sampled three times a day. After 7 days the laparoscopy was repeated and gilts which still had only small follicles in their ovaries were given 250 μg GnRH intravenously the following day. Blood samples were taken frequently before and after GnRH treatment. One week. after administration of GnRH the ovaries were inspected by laparoscopy once more.

The first laparoscopic examination showed that 42 % of the gilts were sexually mature. One gilt had no uterus or ovaries. Twenty gilts had only small follicles in the ovaries and fourteen of these gilts showed ovulatory oestrus 5.5 days (4-7.5 days) after arrival. In these fourteen gilts a rise in the oestradiol-17B level (>30 pmol/1) was seen at an average time of 1.9 days and a rise in LH (preovulatory peak) was seen at an averaged 4.5 days after the start of blood sampling. Six gilts were given 250 ug GnRH. An immediate rise in LH could be seen in all the gilts (mean peak level was 6.18 μg/l) and the elevated levels had a duration of 4 hours. None of the GnRH-treated gilts responded with oestrus symptoms or increased ovarian activity.

Treatment with gonadotropin releasing-hormone in prepubertal gilts at two different ages

To study the effect of GnRH in prepubertal gilts, seven crossbred gilts were treated with saline solution and 250 fig GnRH. In connection with saline and GnRH treatments blood was sampled every 15 min for 4 h, thereafter every 30 min for 2 h and every 60 min for 3 h, and finally every 3 h for 6 days. The ovaries were inspected by laparo-scopy just before and 6 days after GnRH treatment. The first GnRH treatment was undertaken when the gilts had a mean age of 141 days and mean body weight of 66 kg. One gilt was in prooestrus at this treatment. In the other 6 gilts the mean LH level was around 0.5 μg/l during a 4 h period after the saline injection. After the GnRH treatment a LH peak was seen with a mean duration of 4 h and a mean maximum level of 9.2 ± 2.07 μg/1. None of the gilts ovulated or showed oestrus within a week after GnRH treatment, which was confirmed by laparoscopy. The seventh gilt which was in prooestrus had high levels of oestradiol-17β (> 40 pmol/1) at GnRH treatment and no LH peak was seen during a 4 h period after treatment.

Two gilts which had not shown oestrus at an age of 173 days and a mean body weight of 93 kg were treated a second time with 250 μg GnRH. The LH peak had a duration of 4 h and a mean maximum level of 5.3 ± 3.04 μg/l. Neither of these 2 gilts showed oestrus or ovulated within a week after GnRH injection. It was concluded that a single injection of GnRH results in a LH peak but is not enough to stimulate ovulation or oestrus in prepubertal gilts at a mean age either of 141 or 173 days.

Plasma luteinizing hormone response to increasing doses of synthetic gonadotrophin-releasing hormone in heifers

The dosenresponse relationship for a synthetic gonadotrophin-releasing hormone (GnRH) was studied in normally cycling heifers using the area under the luteinizing hormone (LH) curve as a response parameter. Oestrus was synchronized by an injection of 0.5 mg cloprostenol before the experiment started and after the 3rd treatment with GnRH. Treatment with GnRH as assigned in a Latin square included 5 dose levels (0, 10, 50, 100, 250 μg) and 5 treatment days over a period of 22 days. GnRH was capable of inducing an increase of plasma LH within 30 min after injection. Plasma LH response increased with increasing doses of GnRH, the largest increase being observed when the dose was raised from 50 μg to 100 μg. One heifer did not respond to any of the doses applied. The existence of an individual treshold dose of GnRH is suggested.

Primary structure of the ovine hypothalamic luteinizing hormone-releasing factor (LRF) (LH-hypothalamus-LRF-gas chromatography-mass spectrometry-decapeptide-Edman degradation)

The primary structure of ovine hypothalamic hypophysiotropic luteinizing hormone-releasing factor, LRF, has been established as pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH(2) by hydrolysis of the peptide with chymotrypsin or pyrrolidone-carboxylylpeptidase and by analysis of the products by an Edman-dansylation sequencing technique, as well as by mass spectrometry of the derived phenylthiohydantoins. A decapeptide with the proposed primary structure, prepared by total synthesis, gave the same result on sequencing. The synthetic decapeptide possesses the same biological activities as the native ovine LRF. The amino-acid sequence of ovine LRF is identical to that already published for porcine LRF.