Ovarian sensitization to gonadotrophins by human growth hormone. Persistence of the effect beyond the treated cycle

Female gonadal function before and after treatment of acromegaly

CONTEXT

The menstrual cycle is often abnormal in women with acromegaly. Gonadotropin deficiency may be due to a tumor mass effect (macroadenomas) and/or hyperprolactinemia and/or GH excess.

AIM OF THE STUDY

The aim of the study was to analyze the causes of ovarian dysfunction in a large series of patients with acromegaly followed up in a single center.

PATIENTS AND METHODS

Gonadal function was assessed on the basis of menstrual status and hormone assays before and after treatment of acromegaly, between 1985 and 2005, in 55 patients aged from 17 to less than 45 yr.

RESULTS

Seventeen women (31%) were considered to be eugonadal because they had regular menstrual cycles and/or conceived spontaneously. The remaining 38 women had anovulatory cycles. Of these, 11 had hyperprolactinemia and six had hypogonadism due to a mass effect. The cause of the menstrual disturbances was mixed or unclassifiable in 14 cases. In the seven remaining cases, the gonadal dysfunction was likely related to the GH/IGF-I excess, which exerts a direct effect on the gonadotropic axis. Two had polycystic ovary syndrome, which disappeared after normalization of serum GH/IGF-I levels, suggesting that GH/IGF-I excess may also have a direct effect on the ovary. Thirty-eight women became pregnant, and all had healthy children, despite active acromegaly in 12 cases (31%).

CONCLUSION

Gonadal dysfunction is very common in premenopausal women with acromegaly. The potential causes include the lactogenic effect of prolactin, GH, or both on gonadotropic axis. Tumor mass effect or direct effect of GH or IGF-I on the ovary may also participate in ovarian dysfunction.

Pelvic ultrasound evaluation in patients with Turner syndrome during treatment with growth hormone

OBJECTIVES

Treatment with growth hormone (GH), alone or in combination with oxandrolone, is used in patients affected by Turner syndrome to improve growth velocity and adult height. Since GH interacts with gonadotropins in the stimulation of the human ovary, the aim of our study was to evaluate the possible effects of GH administration on uterine and ovarian characteristics.

METHODS

We performed pelvic ultrasound assessment in 29 patients with Turner syndrome aged 7.5-16.6 years (19 with 45,X karyotype; 10 with variant karyotypes) before and during treatment with GH alone. Uterine volume and ovarian size and morphology were compared to those of 23 age-matched girls with Turner syndrome not treated with GH. Both patients and controls were divided into prepubertal and pubertal groups. Cross-sectional and longitudinal studies (before and every 6 months during GH treatment for 2 years) were performed.

RESULTS

We observed a significantly higher uterine anteroposterior diameter and volume in younger (< or = 11 years) GH-treated Turner syndrome girls than in those who were untreated. Also visualization and heterogeneous echopattern of the ovaries were significantly more frequent in treated than in untreated Turner syndrome patients, particularly before the age of 11 years. The longitudinal study showed a significant increase in uterine volume, more related to treatment than to age. Spontaneous breast development and menarche were found more frequently in GH-treated Turner syndrome girls.

CONCLUSION

Growth hormone therapy can have a co-gonadotropin role in patients with Turner syndrome.

Growth hormone does not increase the expression of insulin-like growth factors and their receptor genes in the pre-menopausal human ovary

A growing body of information now supports the existence of a complete intraovarian insulin-like growth factor I (IGF-I) system. Although the precise role of IGF-I in the context of ovarian physiology remains to be determined, it is likely that IGF-I may engage in the amplification of gonadotrophin hormonal action. These facts and experiments with animals establishing the ovaries of multiple species as a site of growth hormone (GH) reception and action have led to the use of recombinant GH (rGH) as an adjunctive agent to potentiate ovulation induction by exogenous gonadotrophins. Whether intraovarian IGF-I plays an intermediary role in GH hormonal action at the ovarian level remains uncertain at present. The aim of this study was to evaluate whether rGH administration to pre-menopausal women could modify the expression of the IGF-I gene in the ovary. The expression of the IGF-I gene was examined in a time-dependent manner in normal pre-menopausal ovaries obtained from nine women treated with rGH and nine control women treated with placebo, using solution hybridization/RNase protection assays. Ovarian tissue samples were obtained 24 h (six women) and 7 days (12 women) following rGH/placebo injection. Total RNA (20 microg) from whole pre-menopausal ovaries (with or without rGH treatment) as well as from human granulosa cells was hybridized with a human IGF-I antisense RNA. IGF-I peptide, but not oestradiol, serum concentrations increased significantly 24 h after rGH injection. IGF-I gene, however, was not expressed in the luteinized granulosa cells and whole pre-menopausal ovaries irrespectively of rGH treatment in ovarian samples analysed both 1 and 7 days following rGH injection. On the contrary, IGF-II mRNA transcribed from the fetal or fetal-neonatal IGF-II promoter and IGF-I receptor mRNA (both used as hybridization control) were both found in whole pre-menopausal ovary and luteinized granulosa cells. Nevertheless, no changes in the hybridization patterns were seen in the absence or presence of rGH. These studies demonstrate that rGH administration to normal premenopausal women does not change the expression of insulin-like growth factors and their receptor genes in the pre-menopausal human ovary. Furthermore, these results provide further evidence against locally produced IGF-I as responsible for any ovarian effects seen in systemic rGH administration.

Growth hormone and ovarian function

Growth and reproductive development are closely co-ordinated during puberty but there is also evidence that growth hormone (GH) may have a physiological role in adult ovarian function. Both GH and the insulin-like growth factors (IGFs) have been shown to augment granulosa cell proliferation and steroidogenesis in the human Graafian follicle, suggesting that GH may act as a 'co-gonadotrophin' at ovarian level. Furthermore, the intra-ovarian 'IGF system' (i.e. IGFs and IGF-binding proteins) may be implicated in folicular atresia and in disorders of follicular function associated with polycystic ovary syndrome (PCOS). The clinical importance of GH to ovarian function in the adult is illustrated by the finding that adjuvant GH treatment reduces the dose of exogenous gonadotrophin which is required to induce folliculogenesis in women with hypogonadotrophic hypogonadism. There is, however, no evidence that GH supplementation is of significant clinical benefit in the management of patients with other ovulatory disorders--including PCOS--or in superovulation protocols for in vitro fertilization.

A new concept of cotreatment with human growth hormone and menotropins in ovulation induction protocols

Follicular development in the primordial and preantral stages is almost completely independent of gonadotrophins or steroids and is mainly dependent on growth factors and local regulators. Since human growth hormone (hGH) was found to facilitate ovarian response to gonadotrophin stimulation, we hypothesized that the administration of hGH in an hypogonadotrophic state and prior to ovarian stimulation with menotropins, may initiate or facilitate the propagation of the primordial and preantral follicles to the gonadotrophin-dependent stages. We suggest that treatment with hGH prior to menotropin administration may be useful to improve results for poor responders to gonadotrophins.

The value of human growth hormone as an adjuvant for ovarian stimulation in a human in vitro fertilization program

The purpose of this study was to evaluate whether the combined treatment of growth hormone (GH) and gonadotropins can improve ovulation stimulation in previously poor responders. Twelve patients who, had suboptimal responses in previous in vitro fertilization cycle were enrolled. They underwent 1 cycle with gonadotropin-releasing hormone analogue (GnRH-a) and gonadotropins and another cycle with GnRH-a, gonadotropins, and GH. Serum gonadotropins, insulin-like growth factor-1 (IGF-1), and sex steroids, including estradiol (E2), progesterone (P4), testosterone, and androstenedione were measured on Day 2 and during ovulation induction. The serum IGF-1 level was higher in the GH cycle. There were no significant differences in the levels of the serum luteinizing hormone, E2, P4, testosterone, and androstenedione between the 2 cycles, so was IGF-1, E2 and P4 in follicular fluid. Co-treatment with GH did not improve the ovarian response. However, the GH cycles had better performance in terms of the number of oocytes fertilized and the pregnancy rate.

Double-blind placebo controlled study: human biosynthetic growth hormone for assisted reproductive technology

OBJECTIVE

To study whether the effect of cotreatment with human biosynthetic GH improves the outcome of poor IVF responders.

DESIGN

A double-blind placebo-controlled study using a GnRH agonist (GnRH-a) and gonadotropin in a "boost" flare-up protocol for ovarian stimulation together with either placebo, 4, or 12 IU of human GH followed by oocyte retrieval and IVF-ET.

PATIENTS

Twenty-two patients with previously demonstrated poor responses in at least two assisted reproductive technology cycles were recruited.

INTERVENTIONS

Pretreatment and post-treatment blood samples and daily morning blood samples during ovarian stimulation were collected after an overnight fast. Human GH or placebo and GnRH-a were administered SC; gonadotropin was administered IM. Oocytes were collected by ultrasound-guided transvaginal aspiration of follicles. Embryos were cultured in vitro and transferred transcervically.

MAIN OUTCOME MEASURES

Serum E2, FSH, GH, insulin-like growth factor-I (IGF-1), IGF binding protein 1 (IGFBP-1), and IGFBP-3 concentrations. Number of FSH ampules, follicles, oocytes, embryos, and pregnancies.

RESULTS

No improvement in cycle outcome was demonstrated with daily adjuvant human GH administration with either 4 or 12 IU. Serum IGF-I levels were highest in the 12 IU human GH group and lowest in the placebo group. Serum IGFBP-3 levels increased 2 days after IGF-I levels in the 12 IU human GH group only. Serum IGFBP-1 levels were unchanged in all groups.

CONCLUSION

Poor IVF responders do not benefit from cotreatment with human GH during their ovarian stimulation.

Low-dose growth hormone-releasing factor may enhance folliculogenesis in regularly menstruating women: a preliminary study

OBJECTIVE

To evaluate the effect of low-dose GH-releasing factor (GRF) on folliculogenesis in regularly menstruating women.

DESIGN

Prospective clinical trial where individual patients served as their own control.

SETTING

Outpatient Reproductive Endocrine/Infertility Clinic of the Los Angeles County-University of Southern California Medical Center, Los Angeles, California.

PATIENTS

Seven regularly menstruating women.

INTERVENTION

During treatment cycles, subjects received 100 micrograms SC GRF on cycle days 2 to 11 and were observed during a control cycle.

MAIN OUTCOME MEASURES

Follicle number and diameter, as well as endometrial thickness were all assessed by vaginal ultrasound and blood was obtained for serum FSH, LH, E2, P, GH, insulin-like growth factor 1 (IGF-1), and insulin-like growth factor binding protein-3.

RESULTS

During cycles treated with GRF, GH, and IGF-1 levels were normal. However, follicular growth rates and E2 to FSH ratios were significantly higher. The day of the peak E2 to follicular diameter ratio after GRF was earlier than in control cycles. Endometrial growth rates were also greater with GRF.

CONCLUSIONS

Our data, although preliminary, support the hypothesis that low doses of GRF may independently stimulate the ovary and enhance folliculogenesis.

The role of growth hormone in ovulation induction

During the last few years the potential importance of intraovarian regulators of follicular development has been recognized, and the effects of various growth factors on granulosa cell responses to gonadotrophins have been extensively investigated. Ovarian responses to exogenous gonadotrophins were improved by adjuvant growth hormone (GH) treatment of GH-deficient patients, and responses to hMG were apparently predicted by estimated GH reserve. However, the results of different studies of GH/hMG cotreatment were equivocal. Therefore, a randomized, prospective, cross-over study protocol between GH/hMG/hCG versus hMG/hCG was undertaken. Whereas 16 pregnancies were achieved in the 26 Clonidine-negative patients (61.5%) either in the GH/hMG cycle (11) or in the succeeding one (5), no benefit was detected in 8 Clonidine-positive patients from the GH/hMG combination. The recently described GH-binding protein (BP) may reflect the GH-receptor. GH-BP levels were evaluated in the sera and follicular fluids (FF) of patients undergoing ovulation induction with either hMG/hCG or GH/hMG/hCG. GH-BP increase in serum correlated with E2, and progesterone (P4) concentrations. The FF GH-BP correlated with serum GH-BP levels. Lower FF GH-BP levels were measured in older compared to younger women, while increased values were obtained both in patients with elevated E2 concentrations in serum and in FF, or when more than five oocytes were retrieved. Primary increased GH-BP in unexplained infertility may suggest a new mechanism whereby excessive GH-BP levels may deprive GH from its receptor and thus decrease the introavarian IGF-I production.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.

Ovulation induction in gonadotrophin-resistant women

The patient who has gonadotrophin-resistant ovaries and who requires ovulation induction or superovulation for IVF presents a serious problem. The diagnosis is usually made in the first treatment cycle which is either abandoned due to a failure of response, requires inordinately high doses of gonadotrophins to induce a response or fails to induce satisfactory oestradiol levels and/or follicular development. This situation is often associated with advanced maternal age and high day 3 concentrations of FSH. The possible treatment strategies that we have described seem to offer only a partial solution to specific subgroups of poor responders. These include protocols of clomiphene/hMG, mini-dose GnRH agonist regimens, and cotreatment with GH, each of which may be found to be effective in individual cases. Taking into account today's increasing demand for pregnancy in older aged women, more research is needed to evolve more efficient solutions for this difficult problem.

Conventional and nonconventional uses of growth hormone

Although GH has been available as a therapeutic agent for the GH-deficient child for more than 30 years, the conditions of its use have yet to be optimized. The availability of biosynthetic material has provided researchers with the opportunity to develop the protocols necessary to begin to finally answer the most fundamental questions pertaining to dose, frequency, and duration of treatment. It has also permitted the initiation of prospective trials in a large number of conditions that result in childhood short stature, with the expectation that some or many of them will be treated effectively and safely. Finally, it has opened the door to an entire spectrum of potentially new uses of GH and other growth factors for so-called nonconventional indications. That these have implications that range from the short-term rapid healing of a burn graft site, to the more efficient induction of ovulation, to the long-term preservation of lean body mass has excited the interest of investigators in many fields of medicine and physiology. Thus, the recent progress reported in this paper is really the beginning of the new research that will take place with GH and growth factors.

The potential relevance of growth hormone to female reproductive physiology and pathophysiology

OBJECTIVE

To assess possible interfacing between the somatotrophic and reproductive axes.

DESIGN

Literature review.

MAIN OUTCOME MEASURES

Ovarian growth hormone reception and action.

RESULTS

The available literature strongly supports a permissive role for the somatotrophic axis in the reproductive process.

CONCLUSIONS

Although a role for growth hormone in reproductive biology appears highly likely, its relevance to the process of puberty and to the normal workings of the menstrual cycle, as well as its possible application in reproductive pathology must await further investigation.