Effects of growth hormone and growth hormone-releasing hormone on steroid synthesis in cultured human luteinizing granulosa cells

Evaluation of growth hormone deficiency in women with unexplained infertility

PURPOSE

Growth hormone (GH) has been recognized to play a regulatory role in female reproduction. It has been reported that infertile GH deficient patients regained fertility after GH replacement. The frequency of GH deficiency is not established in patients diagnosed with unexplained infertility. Here, we aim to present the prevalence of GH deficieny in this patient group.

METHODS

We included patients diagnosed with unexplained infertility throughout 18 months. Insulin tolerance test (ITT) and glucagon stimulation tests (GST) were performed and insufficient response to both tests was required for the diagnosis of GH deficiency.

RESULTS

Twenty-five patients were included in the study, the mean age was 27.4 ± 4.5 years and the median duration of infertility was 60 months (min:14, max:120). Two patients were GH deficient according to GST and 14 to ITT. Two patients (8%) showed lack of response on both tests and were diagnosed with GH deficiency.

CONCLUSION

The rate of GH deficiency among women with unexplained infertility was 8% in this preliminary study. There is need for further studies with larger patient groups to verify the results.

Normal-high IGF-1 level improves pregnancy rate after ovarian stimulation in women treated with growth hormone replacement therapy

Objective

Growth hormone (GH) and insulin-like growth factors (IGFs) are not mandatory for reproductive life, but data suggest their synergistic action with follicle-stimulating hormone throughout ovarian folliculogenesis. We aimed to evaluate the association of IGF-1 level on clinical pregnancy rate after ovarian stimulation, with or without intrauterine insemination, in women with GH deficiency (GHD) treated with GH replacement therapy (GHRT) at conception.

Design and methods

Data from 19 women with both GHD and hypogonadotropic hypogonadism referred to our reproductive medicine department were retrospectively collected. IGF-1 levels were assessed in a single laboratory, and values were expressed in s.d. from the mean.

Results

Amongst the seven patients receiving GHRT during ovarian stimulation, higher IGF-1 levels were significantly associated with clinical pregnancy (+0.4 s.d. vs-1.6 s.d., P = 0.03). Amongst the 24 pregnancies obtained by the 19 infertile patients, pregnancy loss was less frequent with the addition of GHRT than without (1 miscarriage out of 8 total pregnancies vs 4 miscarriages out of 16 total pregnancies).

Conclusions

This is the first study evaluating the association of IGF-1 level on clinical pregnancy rate in GH-treated women at conception. When taking care of female infertility due to hypogonadotropic hypogonadism, practitioners should enquire about the associated GHD and IGF-1 levels. To ensure higher clinical pregnancy chances, practitioners should aim for IGF-1 values at conception, ranging from 0 s.d. to +2 s.d., and, if necessary, could discuss initiation or increase GH treatment. Prospective studies should help strengthen our results.

Growth hormone in fertility and infertility: Mechanisms of action and clinical applications

Secreted by the anterior pituitary gland, growth hormone (GH) is a peptide that plays a critical role in regulating cell growth, development, and metabolism in multiple targeted tissues. Studies have shown that GH and its functional receptor are also expressed in the female reproductive system, including the ovaries and uterus. The experimental data suggest putative roles for GH and insulin-like growth factor 1 (IGF-1, induced by GH activity) signaling in the direct control of multiple reproductive functions, including activation of primordial follicles, folliculogenesis, ovarian steroidogenesis, oocyte maturation, and embryo implantation. In addition, GH enhances granulosa cell responsiveness to gonadotropin by upregulating the expression of gonadotropin receptors (follicle-stimulating hormone receptor and luteinizing hormone receptor), indicating crosstalk between this ovarian regulator and the endocrine signaling system. Notably, natural gene mutation of GH and the age-related decline in GH levels may have a detrimental effect on female reproductive function, leading to several reproductive pathologies, such as diminished ovarian reserve, poor ovarian response during assisted reproductive technology (ART), and implantation failure. Association studies using clinical samples showed that mature GH peptide is present in human follicular fluid, and the concentration of GH in this fluid is positively correlated with oocyte quality and the subsequent embryo morphology and cleavage rate. Furthermore, the results obtained from animal experiments and human samples indicate that supplementation with GH in the in vitro culture system increases steroid hormone production, prevents cell apoptosis, and enhances oocyte maturation and embryo quality. The uterine endometrium is another GH target site, as GH promotes endometrial receptivity and pregnancy by facilitating the implantation process, and the targeted depletion of GH receptors in mice results in fewer uterine implantation sites. Although still controversial, the administration of GH during ovarian stimulation alleviates age-related decreases in ART efficiency, including the number of oocytes retrieved, fertilization rate, embryo quality, implantation rate, pregnancy rate, and live birth rate, especially in patients with poor ovarian response and recurrent implantation failure.

Expression of PTX3, GHR and GDF9 genes in cumulus cells and oocytes in relation to developmental competence of Bos indicus

The present study was conducted to evaluate the level of expression (mRNA) of specific developmental marker genes, viz. Growth Differentiation Factor 9 (GDF9), Growth Hormone Receptor (GHR) and Pentraxin 3 (PTX3) in bovine cumulus cells and oocytes in relation to in vitro developmental competence. Good quality Cumulus- Oocytes- Complexes (COCs) were selected for in vitro maturation and fertilization. The mean percentage of in vitro fertilization performance was 59.84 ± 4.28. The relative quantification values of GDF9 were 2.38, 98.13, 1 and 132.58; GHR were 4.31, 1.47, 1 and 43.58; PTX3 were 0.28, 0, 1 and 0.5 in immature cumulus cells, immature oocyte, mature cumulus cells and mature oocyte respectively when compared to the reference control. The expression of GDF9 gene was found to be up-regulated in oocytes compared to cumulus cells. The expression pattern of GDF9 was relatively more in in vitro matured oocytes compared to cumulus groups. The expression of GHR gene was up-regulated in oocytes. The relative abundance of PTX3 was slightly up-regulated in mature cumulus cells as compared to immature counterparts. Thus, GDF9 and GHR genes could be considered as embryonic developmental markers for bovine oocytes, while PTX3 gene for bovine cumulus cells.

Central growth hormone signaling is not required for the timing of puberty

Growth hormone (GH) is a key factor in the regulation of body growth, as well as a variety of other cellular and metabolic processes. Neurons expressing kisspeptin and leptin receptors (LepR) have been shown to modulate the hypothalamic-pituitary-gonadal (HPG) axis and are considered GH-responsive. The presence of functional GH receptors (GHR) in these neural populations suggests that GH may regulate the HPG axis via a central mechanism. However, there have been no studies evaluating whether or not GH-induced intracellular signaling in the brain plays a role in the timing of puberty or mediates the ovulatory cycle. Towards the goal of understanding the influence of GH on the central nervous system as a mediator of reproductive functions, GHR ablation was induced in kisspeptin and LepR expressing cells or in the entire brain. The results demonstrated that GH signaling in specific neural populations can potentially modulate the hypothalamic expression of genes related to the reproductive system or indirectly contribute to the progression of puberty. GH action in kisspeptin cells or in the entire brain was not required for sexual maturation. On the other hand, GHR ablation in LepR cells delayed puberty progression, reduced serum leptin levels, decreased body weight gain and compromised the ovulatory cycle in some individuals, while the lack of GH effects in the entire brain prompted shorter estrous cycles. These findings suggest that GH can modulate brain components of the HPG axis, although central GH signaling is not required for the timing of puberty.

Multiple Effects of Growth Hormone in the Body: Is it Really the Hormone for Growth?

In this review, we analyze the effects of growth hormone on a number of tissues and organs and its putative role in the longitudinal growth of an organism. We conclude that the hormone plays a very important role in maintaining the homogeneity of tissues and organs during the normal development of the human body or after an injury. Its effects on growth do not seem to take place during the fetal period or during the early infancy and are mediated by insulin-like growth factor I (IGF-I) during childhood and puberty. In turn, IGF-I transcription is dependent on an adequate GH secretion, and in many tissues, it occurs independent of GH. We propose that GH may be a prohormone, rather than a hormone, since in many tissues and organs, it is proteolytically cleaved in a tissue-specific manner giving origin to shorter GH forms whose activity is still unknown.

Regimen of ovarian stimulation affects oocyte and therefore embryo quality

Without any doubt the regimen used to mature multiple capable oocytes for IVF impacts IVF outcomes. Studies have indicated that the inclusion of LH activity, adjuvant agents such as growth hormone (GH), and regimens providing for simultaneous action of both LH and FSH during final oocyte maturation may have beneficial effects on IVF outcomes. Because of the difficulty in improving IVF outcomes in poor responders, the studies on GH are of particular interest. As pointed out in this review, the apparent beneficial effects of GH on oocyte competence may also apply to older women or to normal responders with reduced embryo quality. A much more difficult question is whether and how much ovarian stimulation impacts on oocyte competence. Paradoxically it seems that there are not demonstrated differences between the stimulated and the natural unstimulated cycle, whereas studies in laboratory animals and IVF patients have shown deleterious effects of higher compared with lower doses of gonadotropins. Recent studies suggest that the use of high doses of gonadotropins as an independent factor correlates negatively with the probability of live birth, whereas a high ovarian response per se is associated with better cumulative pregnancy rates, owing to the availability of more euploid and good-quality embryos. Although adjunctive use of androgens has not been discussed here, it is briefly covered in the first review of this series.

Growth hormone and reproduction: a review of endocrine and autocrine/paracrine interactions

The somatotropic axis, consisting of growth hormone (GH), hepatic insulin-like growth factor I (IGF-I), and assorted releasing factors, regulates growth and body composition. Axiomatically, since optimal body composition enhances reproductive function, general somatic actions of GH modulate reproductive function. A growing body of evidence supports the hypothesis that GH also modulates reproduction directly, exerting both gonadotropin-dependent and gonadotropin-independent actions in both males and females. Moreover, recent studies indicate GH produced within reproductive tissues differs from pituitary GH in terms of secretion and action. Accordingly, GH is increasingly used as a fertility adjunct in males and females, both humans and nonhumans. This review reconsiders reproductive actions of GH in vertebrates in respect to these new conceptual developments.

How to improve the probability of pregnancy in poor responders undergoing in vitro fertilization: a systematic review and meta-analysis

OBJECTIVE

To systematically review the literature to identify randomized controlled trials, which evaluate interventions aiming to improve the probability of pregnancy in poor responders undergoing in vitro fertilization (IVF).

DESIGN

Systematic review and meta-analysis.

SETTING

University-based hospital.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Pregnancy rate.

RESULT(S)

Twenty-two eligible randomized controlled trials were identified that evaluated in total 15 interventions to increase pregnancy rates in poor responders. Based on limited evidence, the only interventions that appear to increase the probability of pregnancy were the addition of GH to ovarian stimulation (odds ratio for live birth: 5.22, confidence interval: 95% 1.09-24.99) and the performance of embryo transfer on day 2 compared with day 3 (ongoing pregnancy rate: 27.7% vs. 16.3%, respectively; difference: +11.4, 95% confidence interval: +1.6 to +21.0).

CONCLUSION(S)

Insufficient evidence exists to recommend most of the treatments proposed to improve pregnancy rates in poor responders. Currently, there is some evidence to suggest that addition of GH, as well as performing embryo transfer on day 2 versus day 3, appear to improve the probability of pregnancy.

Effects of growth hormone on in vitro maturation of germinal vesicle of human oocytes retrieved from small antral follicles

PURPOSE

Evaluation of the effect of GH, administered in vivo, on in vitro maturation of human GV oocytes obtained from small follicles.

METHODS

The study included 88 ICSI women stimulated with long agonist protocol. They were randomly allocated to two groups (Group 1, 44 women with 86 GV oocytes), were cotreated with GH (Group 2, no GH: 44 women with 67 GV oocytes). GV oocytes from small follicles were matured in vitro, injected, and their development observed.

RESULTS

Resumption of meiosis was significantly higher in Group 1 compared to Group 2 (60 and 37.3% respectively). Significantly more M2 oocytes were obtained in Group 1 than in Group 2 (45.5 and 23.9% respectively). Fertilization rates were also significantly higher (51.9 and 18.8% respectively). No embryos were obtained in Group 2, whereas 21.1% of fertilized oocytes in Group 1 cleaved into class A embryos.

CONCLUSION

In vivo administration of GH enhanced in vitro maturation and fertilization of human GV oocytes retrieved from small antral follicles.

Polycystic ovary syndrome: evidence for reduced 3 beta-hydroxysteroid dehydrogenase gene expression in human luteinizing granulosa cells

In a preview study we found that luteinizing granulosa cells from follicles of patients with polycystic ovary syndrome (PCOS) have a reduced capacity to synthesize progesterone in vitro. Because the 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase (3 beta-HSD) is an important enzyme for the biosynthesis of progesterone, the reduced capacity of PCO luteinizing granulosa cells to synthesize progesterone in vitro may be due to reduced 3 beta-HSD gene expression. A reverse transcriptase polymerase chain reaction for 3 beta-HSD was performed and the relative intensity of signals for 3 beta-HSD was evaluated using computer-assisted densitometry. Cells from polycystic ovaries expressed less 3 beta-HSD in follicles < or 10 mm (p < 0.05) and in follicles > or 16 mm (p < 0.05) than cells from normal ovaries. Furthermore, after human chorionic gonadotropin stimulus (50 ng/ml), cells from polycystic ovaries expressed less 3 beta-HSD in follicles > or = 16 mm (p < 0.01) than cells from normal ovaries. The data show that there is a specific change in the gene expression of 3 beta-HSD in PCO granulosa cells resulting in a suppressed capacity to secrete progesterone.

Does growth hormone-releasing factor assist follicular development in poor responder patients undergoing ovarian stimulation for in-vitro fertilization?

Treatment with growth hormone-releasing factor (GRF) has been reported to improve the ovarian response to gonadotrophins in women who respond poorly to ovarian stimulation during in-vitro fertilization (IVF). The efficacy and tolerability of GRF were studied in a randomized, double-blind, placebo-controlled trial involving 196 patients. Following down-regulation with a gonadotrophin-releasing hormone agonist (GnRHa), patients were randomized to receive GRF (500 microg twice daily; n = 96) or placebo (n = 100) in addition to follicle stimulating hormone (FSH); treatment was continued until human chorionic gonadotrophin was given, or for a maximum of 14 days. GRF had no significant effect on the mean number of follicles with a diameter of >/=16 mm (GRF: 3.26 +/- 2.29; placebo: 3.27 +/- 2.30; P = 0.95), the number of FSH ampoules required to achieve ovarian stimulation (GRF: 55.2 +/- 16. 4; placebo: 54.9 +/- 17.2; P = 0.50), or on secondary measures of ovarian response and treatment outcome. There were, however, significant increases in circulating growth hormone (GH) and insulin-like growth factor (IGF)-1 concentrations. GRF was well tolerated. It is concluded that, despite producing significant increases in GH and IGF-1, concomitant treatment with GRF does not improve the ovarian response to FSH in poorly responsive women undergoing IVF.