Morphological assessment of the effect of growth hormone on preantral follicles from 11-day-old mice in an in vitro culture system

Effect of different growth hormone pretreatment times in assisted reproductive therapy for patients with diminished ovarian reserve: A retrospective pilot cohort study

This study aimed to evaluate the effect of different growth hormone (GH) pretreatment times in assisted reproductive therapy in patients with diminished ovarian reserve (DOR). A retrospective pilot cohort analysis was performed on patients with DOR receiving GH pretreatment in the Assisted Reproduction Unit of Sir Run Run Shaw Hospital. A total of 1459 patients met the criteria and were divided into four groups according to GH pretreatment time as follows: 53 were in the 2-month pretreatment group (GH1), 400 were in the 1-month pretreatment group (GH2), 414 were in the ovulation induction period pretreatment group (GH3), and 592 were in the non-GH pretreatment group (control group). In addition, GH1, GH2, and GH3 were combined in the GH pretreatment group. Baseline characteristics and treatment outcomes were compared between the groups. The number of oocytes retrieved in the GH pretreatment, GH1, GH2, and GH3 groups was significantly higher than that in the control group (all P < .01). The numbers of oocytes retrieved in the GH1 and GH2 groups were similar but were nominally higher than those in the GH3 group. Estradiol concentrations in the GH pretreatment, GH2, and GH3 groups were significantly higher than those in the control group on the day of human chorionic gonadotropin injection (all P < .01). In the GH1 group, 22 patients had >1 assisted reproductive therapy cycle (non-GH pretreatment) before GH pretreatment, and the number of oocytes retrieved in the GH pretreatment cycle was higher than that in the non-GH pretreatment cycle, but this was not significant. These findings suggest that the GH pretreatment time was appropriately prolonged, and the number of oocytes retrieved nominally increased. In patients with DOR, GH pretreatment improved treatment outcomes. More than 1 month of GH pretreatment did not increase the number of oocytes retrieved.

Fertility issues in hypopituitarism

Women with hypopituitarism have lower fertility rates and worse pregnancy outcomes than women with normal pituitary function. These disparities exist despite the use of assisted reproductive technologies and hormone replacement. In women with hypogonadotropic hypogonadism, administration of exogenous gonadotropins can be used to successfully induce ovulation. Growth hormone replacement in the setting of growth hormone deficiency has been suggested to potentiate reproductive function, but its routine use in hypopituitary women remains unclear and warrants further study. In this review, we will discuss the clinical approach to fertility in a woman with hypopituitarism.

Does growth hormone supplementation of in vitro fertilization/intracytoplasmic sperm injection improve cumulative live birth rates in women with poor embryonic development in the previous cycle?

BACKGROUND

Growth hormone (GH) has been proposed as an adjunct in in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles, especially in women with poor ovarian response. However, it is unclear whether GH supplementation is effective in women with poor embryonic development in the previous IVF cycle. The aim of this study was to evaluate the effectiveness of GH supplementation in IVF/ICSI cycles in women with poor embryonic development in the previous cycle.

METHODS

This is a retrospective cohort study from a public fertility center in China, in which we performed propensity score-matching (PSM) for female age and AFC in a ratio of 1:1. We compared the cumulative live birth rate per started cycle, as well as a series of secondary outcomes. We included 3,043 women with poor embryonic development in the previous IVF/ICSI cycle, of which 1,326 had GH as adjuvant therapy and 1,717 had not. After PSM, there were 694 women in each group.

RESULTS

After PSM, multivariate analyses showed the cumulative live birth rate to be significantly higher in the GH group than the control group [N = 694, 34.7% vs. N = 694, 27.5%, risk ratio (RR): 1.4 (95%CI: 1.1-1.8)]. Endometrial thickness, number of oocytes retrieved, number of embryos available, and number of good-quality embryos were significantly higher in the GH group compared to controls. Pregnancy outcomes in terms of birth weight, gestational age, fetal sex, preterm birth rate, and type of delivery were comparable. When we evaluated the impact of GH on different categories of female age, the observed benefit in the GH group did not appear to be significant. When we assessed the effect of GH in different AFC categories, the effect of GH was strongest in women with an AFC5-6 (32.2% versus 19.5%; RR 2.0; 95% CI 1.2-3.3).

CONCLUSIONS

Women with poor embryonic quality in the previous IVF/ICSI cycles have higher rates of cumulative live birth with GH supplementation.

Metabolic hormones are integral regulators of female reproductive health and function

The female reproductive system is strongly influenced by nutrition and energy balance. It is well known that food restriction or energy depletion can induce suppression of reproductive processes, while overnutrition is associated with reproductive dysfunction. However, the intricate mechanisms through which nutritional inputs and metabolic health are integrated into the coordination of reproduction are still being defined. In this review, we describe evidence for essential contributions by hormones that are responsive to food intake or fuel stores. Key metabolic hormones-including insulin, the incretins (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), growth hormone, ghrelin, leptin, and adiponectin-signal throughout the hypothalamic-pituitary-gonadal axis to support or suppress reproduction. We synthesize current knowledge on how these multifaceted hormones interact with the brain, pituitary, and ovaries to regulate functioning of the female reproductive system, incorporating in vitro and in vivo data from animal models and humans. Metabolic hormones are involved in orchestrating reproductive processes in healthy states, but some also play a significant role in the pathophysiology or treatment strategies of female reproductive disorders. Further understanding of the complex interrelationships between metabolic health and female reproductive function has important implications for improving women's health overall.

Effects of Growth Hormone on Adult Human Gonads: Action on Reproduction and Sexual Function

Growth hormone (GH), which is commonly considered to be a promoter of growth and development, has direct and indirect effects on adult gonads that influence reproduction and sexual function of humans and nonhumans. GH receptors are expressed in adult gonads in some species including humans. For males, GH can improve the sensitivity of gonadotropins, contribute to testicular steroidogenesis, influence spermatogenesis possibly, and regulate erectile function. For females, GH can modulate ovarian steroidogenesis and ovarian angiogenesis, promote the development of ovarian cells, enhance the metabolism and proliferation of endometrial cells, and ameliorate female sexual function. Insulin-like growth factor-1 (IGF-1) is the main mediator of GH. In vivo, a number of the physiological effects of GH are mediated by GH-induced hepatic IGF-1 and local IGF-1. In this review, we highlight the roles of GH and IGF-1 in adult human gonads, clarify potential mechanisms, and explore the efficacy and the risk of GH supplementation in associated deficiency and assisted reproductive technologies. Besides, the effects of excess GH on adult human gonads are discussed as well.

The Clinical Application of Growth Hormone and Its Biological and Molecular Mechanisms in Assisted Reproduction

Growth hormone (GH) has been used as a co-gonadotrophin in assisted reproduction, particularly in poor ovarian responders. The application of GH has been alleged to activate primordial follicles and improve oocyte quality, embryo quality, and steroidogenesis. However, the effects of GH on the live birth rate among women is controversial. Additionally, although the basic biological mechanisms that lead to the above clinical differences have been investigated, they are not yet well understood. The actions of GH are mediated by GH receptors (GHRs) or insulin-like growth factors (IGFs). GH regulates the vital signal transduction pathways that are involved in primordial follicular activation, steroidogenesis, and oocyte maturation. However, the therapeutic windows and duration of GH administration during assisted reproductive technology require further investigation. The review aimed to clarify the role of GH in human fertility from a molecular and biological point of view to provide evidence for proper GH administration.

The insulin-like growth factor and its players: their functions, significance, and consequences in all aspects of ovarian physiology

Background

Insulin-like growth factor (IGF) has unique and well-known functions in female fertility, according to documents reporting improved yield of oocytes, reinforced quality of the embryo, and enhanced live births with simultaneous reduction of miscarriage. However, there is no detailed information on the bio-mechanisms linking such clinical differences.

Main body

IGF and its receptors are expressed in a variety of tissues in the reproductive system such as granulosa cells, oocytes, and theca cells. Hence, the development of female gametes may be directly regulated by IGF, thereby affecting gamete quality and so its competence for implantation. IGF is a central player in changing the fate of cells during survival and proliferation through the modulation of leading signaling pathways, including Jak/STAT, MAP kinase/ERK, and PI3K/Akt, and subsequent impacts on steroidogenesis and cell division.

Conclusion

The current review aims to scrutinize the performance of IGF to regulate the normal ovarian, and its impacts on cell signaling pathways and resulting alterations in steroidogenesis and cell proliferation. The function of IGF and its receptor has been reviewed in female fertility at both molecular and biochemical levels.

The role of growth hormone for fertility in women with hypopituitarism

Growth hormone (GH) is an important regulator of the female reproductive system. In vitro and non-human in vivo studies demonstrate a role of GH in steroidogenesis, folliculogenesis, and post-fertilization development. Given its ability to modulate the reproductive system and potentiate the effects of gonadotropins, a beneficial role of GH replacement therapy to optimize fertility has been suggested. Women with hypopituitarism have lower pregnancy and live birth rates. Limited data suggest a role of GH in enhancing fertility management in women with hypopituitarism. GH replacement therapy may be especially relevant in women with hypopituitarism as well as in women considered poor ovarian responders and require assisted reproductive techniques.

Growth Hormone Cotreatment for Low-Prognosis Patients According to the POSEIDON Criteria

BACKGROUND

Poor ovarian response (POR) remains one of the most challenging conditions in assisted reproduction technology. Previous studies seemed to indicate that growth hormone (GH) was a potential solution for the dilemma of POR; however, the role GH played on the low-prognosis patients diagnosed and stratified by the POSEIDON criteria remains indistinct.

METHODS

This retrospective study was performed among women with POR according to the POSEIDON criteria who failed a previous in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycle, and the subsequent cycle was under GH cotreatment and conducted within 12 months. These participants were stratified into four groups according to the POSEIDON criteria. The comparison was implemented between the failed cycle and the cycle treated with GH. Generalized estimating equation (GEE) multivariate regression was applied for data analysis.

RESULTS

A total of 428 low-prognosis women were included in this study. GH supplementation improved the live birth rates (47.66%, 28.33%, 45.45%, and 24.07%; in groups 1, 2, 3, and 4, respectively) and the clinical pregnancy rates (OR 19.16, 95% CI 7.87-46.63, p < 0.001; OR 7.44, 95% CI 1.65-33.55, p = 0.009; OR 10.19, 95% CI 2.39-43.52, p = 0.002; OR 27.63, 95% CI 4.46-171.11, p < 0.001; in groups 1, 2, 3, and 4, respectively) in all four POSEIDON groups. The number of oocytes retrieved was significantly elevated in the subgroups with normal ovarian reserve (IRR 1.47, 95% CI 1.36-1.59, p < 0.001; IRR 1.31, 95% CI 1.15-1.49, p < 0.001; in groups 1 and 2, respectively). The number of day-3 good-quality embryos was significantly elevated in the subgroups with either normal ovarian reserve or aged young (IRR 2.13, 95% CI 1.78-2.56, p < 0.001; IRR 1.54, 95% CI 1.26-1.89, p < 0.001; IRR 1.47, 95% CI 1.10-1.98, p = 0.010; in groups 1, 2, and 3, respectively).

CONCLUSION

Growth hormone cotreatment could ameliorate the pregnancy outcome for women with POR under the POSEIDON criteria who failed a previous IVF/ICSI cycle. The application of growth hormone for low-prognosis women who experienced a failed cycle might be considered and further studied.

The effect of growth hormone supplementation in poor ovarian responders undergoing IVF or ICSI: a meta-analysis of randomized controlled trials

PURPOSE

The aim of this meta-analysis was to evaluate the effect of growth hormone (GH) supplementation in poor responders undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).

METHODS

PubMed, MEDLINE and Cochrane Library databases were searched for the identification of relevant randomized controlled trials. Outcome measures were live birth rate, clinical pregnancy rate, miscarriage rate, cycle cancelation rate, number of retrieved oocytes and total dose of gonadotropin.

RESULTS

Fifteen randomized controlled trails (RCTs) involving 1448 patients were eligible for the analysis. GH supplementation improved live birth rate (RR, 1.74; 95% CI, 1.19-2.54), clinical pregnancy rate (RR, 1.65; 95% CI, 1.31-2.08) and retrieved oocytes number (SMD, 0.72; 95% CI, 0.28-1.16), while reducing cancelled cycles rate (RR, 0.62; 95% CI, 0.44-0.85) and dose of Gonadotropin (SMD,-1.05 95% CI, - 1.62 - -0.49) for poor ovarian response patients. Besides, there was no significant difference in the miscarriage rate between GH group and control group.

CONCLUSIONS

Based on the limited available evidence, growth hormone supplementation seems to improve IVF/ICSI outcomes for poor ovarian responders. Further randomized controlled trials with large sample sizes are required to clarify the effect of GH adjuvant therapy in the treatment of women with poor ovarian response.

Effect of somatotropin on survival and diameter of bovine preantral follicles

ABSTRACT The aim of this study was to evaluate the effect of Recombinant bovine somatotropin (rbST) on survival and diameter of bovine preantral ovarian follicles (PAOF) cultured in vitro. Ovaries were collected from adult cows and fragments of ovarian cortex were immediately fixed (non-cultured control) or cultured in vitro in α-MEM+ alone or containing 10, 50, 100 or 1,000ng/mL rbST. The fragments were processed for Classical Histology and Transmission Electron Microscopy. After one and seven days of culture, the percentage of normal follicles in the non-cultured control was superior (P< 0.05) to the follicles cultured in α-MEM+ alone or with different rbST concentrations. The oocyte and follicular mean diameter did not increase during the culture for one and seven days, both in media containing rbST and in the medium without this hormone. The only medium in which there was no reduction in follicular diameter with the time of culture was the medium without rbST. Ultrastructural damage in PAOF cultured in vitro was found. It is concluded that the use of rbST at different concentrations in in situ culture of bovine preantral follicles has no beneficial effects on survival and growth of bovine PAOF.

Evidence that growth hormone can improve mitochondrial function in oocytes from aged mice

Decline in successful conception decreases more rapidly after 38 years of age owing to follicular depletion and decreased oocyte quality. However, limited information is available regarding the underlying mechanism and the useful treatment. This study aimed to evaluate the effects of growth hormone supplementation on oocyte maturation in vivo in aged and young mice and to determine its effect on mitochondrial function. The influence of three different doses of recombinant human growth hormone (rhGH) (0.4, 0.8 and 1.6 mg/kg/day) for 8 weeks before ovarian stimulation was analyzed. Superovulated oocytes were released from the oviduct of 12-week-old and 40-week-old female C57BL/6J mice 14-16 h after administration of human chorionic gonadotropin. Ovarian follicle and morphological analysis and oocyte maturation parameters were then evaluated. This study is the first, to our knowledge, to report that medium- and high-dose rhGH significantly increases antral follicles in aged mice but anti-Müllerian hormone (AMH) levels. Furthermore, derived oocytes, MII-stage oocyte rate, ATP levels, mitochondrial membrane potential and frequencies of homogeneous mitochondrial distribution increased. In contrast, in both aged and young mice, the mtDNA copy numbers per oocyte were similar before rhGH administration, and upon saline administration, they did not differ significantly. We conclude that medium-dose rhGH supplementation before standard ovarian stimulation regimens improves oocyte quality in aged mice, probably by enhancing mitochondrial functionality.

Impact of recombinant bovine somatotropin, progesterone, and estradiol benzoate on ovarian follicular dynamics in Bos taurus taurus cows using a protocol for estrus and ovulation synchronization

This study aimed to evaluate the effect of recombinant bovine somatotropin (bST) in combination with progesterone (P4) and estradiol benzoate (EB) on ovarian follicular dynamics using a protocol for estrus and ovulation synchronization in crossbred Bos taurus taurus cows. Twenty-four non-lactating multiparous cows were randomly assigned to two groups: the recombinant bovine somatotropin group (GbST; n = 11) received an intravaginal P4 device (1.5 g), estradiol benzoate (EB = 1.0 mg IM), bST (500 mg SC), and an ovarian ultrasonography (US) on day zero (d0 = beginning of the study); d-cloprostenol (150 μg, IM), US, and P4 removal on d8; 1.0 mg of EB (IM) on d9; and US on d10 and d15. On the other hand, to the control group (GC; n = 13), the same protocol as the GbST was applied, except for the non-receipt of bST on d0. The follicles were measured and evaluated on d0, d8, and d10, as were the corpora lutea (CL) on d15 (using ultrasonography). The effect of the two treatments (GbST vs. GC) on the follicle size, CL (F-test), and ovulation rate (logistic regression) were evaluated. The GbST showed a greater follicle diameter on d10 (14.5 mm) than the GC (12.1 mm; P < 0.03), as well as a greater diameter of CL on d15 (19.7 vs. 16.9 mm, P < 0.01). In addition, in the former, the ovulation rate (90.9 vs. 69.2%, P = 0.09) was observed to be greater. It was concluded that the combination of bST, P4, and EB in synchronization for estrus and ovulation protocols significantly increased the diameter of the preovulatory follicle, produced a higher follicular growth rate, and a greater diameter of the corpus luteum. Additionally, there was a higher percentage of cows with ovulation compared to the group that did not receive bST.

Application of Growth Hormone in in vitro Fertilization

Growth hormone (GH) is a peptide hormone secreted mainly by the anterior part of the pituitary gland and plays a critical role in cell growth, development, and metabolism throughout the body. GH can not only directly influence human oocytes and cumulus cells but also indirectly improve oocyte quality through activating synthesis of insulin-like growth factor-I or promoting follicle-stimulating hormone-induced ovarian steroidogenesis. Since GH can regulate female and male infertility, it has been applied in the management of infertility for many years, especially in patients with poor ovarian response or poor prognosis. During ovarian stimulation, GH administration might improve the success rate of in vitro fertilization (IVF) probably through the beneficial effects of GH on oocyte quality as indicated by a higher number of mature oocytes and embryos arriving at the transfer stage and a higher fertility rate in GH-treated patients. However, there is still great controversy in the application of GH in IVF. While some researchers showed that pregnancy, implantation and live birth rates could be increased by ovarian pretreatment with GH, others did not support GH as an effective adjuvant for infertility treatment because the live birth rate was not increased. This study reviewed and summarized recent advancements and benefits in clinical application of GH, trying to reach a just unbiased conclusion regarding the effect of GH therapy in IVF.

Growth Hormone and Insulin-Like Growth Factor Action in Reproductive Tissues

The role of growth hormone (GH) in human fertility is widely debated with some studies demonstrating improvements in oocyte yield, enhanced embryo quality, and in some cases increased live births with concomitant decreases in miscarriage rates. However, the basic biological mechanisms leading to these clinical differences are not well-understood. GH and the closely-related insulin-like growth factor (IGF) promote body growth and development via action on key metabolic organs including the liver, skeletal muscle, and bone. In addition, their expression and that of their complementary receptors have also been detected in various reproductive tissues including the oocyte, granulosa, and testicular cells. Therefore, the GH/IGF axis may directly regulate female and male gamete development, their quality, and ultimately competence for implantation. The ability of GH and IGF to modulate key signal transduction pathways such as the MAP kinase/ERK, Jak/STAT, and the PI3K/Akt pathway along with the subsequent effects on cell division and steroidogenesis indicates that these growth factors are centrally located to alter cell fate during proliferation and survival. In this review, we will explore the function of GH and IGF in regulating normal ovarian and testicular physiology, while also investigating the effects on cell signal transduction pathways with subsequent changes in cell proliferation and steroidogenesis. The aim is to clarify the role of GH in human fertility from a molecular and biochemical point of view.

The Effect of Growth Hormone on the Clinical Outcomes of Poor Ovarian Reserve Patients Undergoing in vitro Fertilization/Intracytoplasmic Sperm Injection Treatment: A Retrospective Study Based on POSEIDON Criteria

The aim of this retrospective analysis is to explore whether growth hormone (GH) pretreatment is beneficial for patients with poor ovarian reserve undertaking in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment. Poor ovarian reserve patients with anti-Mullerian hormone (AMH) <1.2 ng/mL were recruited and divided into the GH adjuvant group (GH+ group) and the counterpart without GH pretreatment (GH- group). One-to-one case-control matching was performed to adjust essential confounding factors between the GH+ group and GH- group. A total of 676 cycles were included in the present study with 338 cycles in each group. Conventional ovarian stimulation protocols were applied for ART treatment. Patients were further divided into POSEIDON group 3 (PG3, age <35 years) and POSEIDON group 4 (PG4, age ≥35 years), based on POSEIDON criteria. The demographic data, cycle characteristics, and clinical outcomes between the GH+ group and GH- group, as well as in the further stratified analysis of PG3 and PG4 were compared. GH adjuvant showed a beneficial effect on the ovarian response and live birth rate in poor ovarian reserve patients. Further stratification revealed that in PG4, there was a significantly increased number of good-quality embryos in the GH+ group compared to the GH- group (1.58 ± 1.71 vs. 1.25 ± 1.55, P = 0.032), accompanied by a reduced miscarriage rate and a greatly improved live birth rate (29.89 vs. 17.65%, P = 0.028). GH adjuvant failed to promote the live birth rate in PG3. In conclusion, GH pretreatment is advantageous by elevating ovarian response and correlated with an improved live birth rate and reduced miscarriage rate in POSEIDON poor ovarian reserve patients older than 35.

Impact of recombinant bovine somatotropin, progesterone, and estradiol benzoate on ovarian follicular dynamics in Bos taurus taurus cows using a protocol for estrus and ovulation synchronization

This study aimed to evaluate the effect of recombinant bovine somatotropin (bST) in combination with progesterone (P4) and estradiol benzoate (EB) on ovarian follicular dynamics using a protocol for estrus and ovulation synchronization in crossbred Bos taurus taurus cows. Twenty-four non-lactating multiparous cows were randomly assigned to two groups: the recombinant bovine somatotropin group (GbST; n&#x202F;=&#x202F;11) received an intravaginal P4 device (1.5&#x202F;g), estradiol benzoate (EB&#x202F;=&#x202F;1.0&#x202F;mg IM), bST (500&#x202F;mg SC), and an ovarian ultrasonography (US) on day zero (d0&#x202F;=&#x202F;beginning of the study); d-cloprostenol (150&#x202F;μg, IM), US, and P4 removal on d8; 1.0&#x202F;mg of EB (IM) on d9; and US on d10 and d15. On the other hand, to the control group (GC; n&#x202F;=&#x202F;13), the same protocol as the GbST was applied, except for the non-receipt of bST on d0. The follicles were measured and evaluated on d0, d8, and d10, as were the corpora lutea (CL) on d15 (using ultrasonography). The effect of the two treatments (GbST vs. GC) on the follicle size, CL (F-test), and ovulation rate (logistic regression) were evaluated. The GbST showed a greater follicle diameter on d10 (14.5&#x202F;mm) than the GC (12.1&#x202F;mm; P&#x202F;<&#x202F;0.03), as well as a greater diameter of CL on d15 (19.7 vs. 16.9&#x202F;mm, P&#x202F;<&#x202F;0.01). In addition, in the former, the ovulation rate (90.9 vs. 69.2%, P&#x202F;=&#x202F;0.09) was observed to be greater. It was concluded that the combination of bST, P4, and EB in synchronization for estrus and ovulation protocols significantly increased the diameter of the preovulatory follicle, produced a higher follicular growth rate, and a greater diameter of the corpus luteum. Additionally, there was a higher percentage of cows with ovulation compared to the group that did not receive bST.

The Growth of Preantral Follicles and the Impact of Different Supplementations and Circumstances: A Review Study with Focus on Bovine and Human Preantral Follicles

One of the most important concerns cancer survivors face is fertility. Current treatment modalities often result in damage to the reproductive system. Different options have been proposed to preserve the fertility of affected women, and many attempts have been made to improve their chance of childbearing after therapy. Cryopreservation of ovarian tissue and follicles before the onset of cancer treatment and then either transplantation of ovarian tissue or culture of ovarian tissue and individual follicles in vitro is a commonly cited approach. Extensive research is being done to design an optimal condition for the culture of ovarian follicles. Improving follicle culture systems by understanding their actual growth needs might be a crucial step toward fertility preservation in cancer patients. This review article will try to provide a summary of the role of different factors and conditions on growth of human and bovine preantral follicles in vitro.

Autocrine/paracrine proliferative effect of ovarian GH and IGF-I in chicken granulosa cell cultures

It is known that growth hormone (GH) and its receptor (GHR) are expressed in granulosa cells (GC) and thecal cells during the follicular development in the hen ovary, which suggests GH is involved in autocrine/paracrine actions in the female reproductive system. In this work, we show that the knockdown of local ovarian GH with a specific cGH siRNA in GC cultures significantly decreased both cGH mRNA expression and GH secretion to the media, and also reduced their proliferative rate. Thus, we analyzed the effect of ovarian GH and recombinant chicken GH (rcGH) on the proliferation of pre-hierarchical GCs in primary cultures. Incubation of GCs with either rcGH or conditioned media, containing predominantly a 15-kDa GH isoform, showed that both significantly increased proliferation as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, proliferating cell nuclear antigen (PCNA) quantification and ((3)H)-thymidine incorporation ((3)H-T) assays in a dose response fashion. Both, locally produced GH and rcGH also induced the phosphorylation of Erk1/2 in GC cultures. Furthermore, GH increased IGF-I synthesis and its release into the GC culture incubation media. These results suggest that GH may act through local IGF-I to induce GC proliferation, since IGF-I immunoneutralization completely abolished the GH-induced proliferative effect. These data suggest that GH and IGF-I may play a role as autocrine/paracrine regulators during the follicular development in the hen ovary at the pre-hierarchical stage.

Molecular and cellular mechanisms for the regulation of ovarian follicular function in cows

Ovary is an important organ that houses the oocytes (reproductive cell). Oocyte growth depends on the function of follicular cells such as the granulosa and theca cells. Two-cell two gonadotropin systems are associated with oocyte growth and follicular cell functions. In addition to these systems, it is also known that several growth factors regulate oocyte growth and follicular cell functions. Vascular endothelial growth factor (VEGF) is involved in thecal vasculature during follicular development and the suppression of granulosa cell apoptosis. Metabolic factors such as insulin, growth hormone (GH) and insulin-like growth factor 1 (IGF-1) also play critical roles in the process of follicular development and growth. These factors are associated not only with follicular development, but also with follicular cell function. Steroid hormones (estrogens, androgens, and progestins) that are secreted from follicular cells influence the function of the female genital tract and its affect the susceptibility to bacterial infection. This review covers our current understanding of the mechanisms by which gonadotrophins and/or steroid hormones regulate the growth factors in the follicular cells of the bovine ovary. In addition, this review describes the effect of endotoxin on the function of follicular cells.

Impact of growth hormone (GH) and follicle stimulating hormone (FSH) on in vitro canine preantral follicle development and estradiol production

OBJECTIVE

Evaluate the effect of different concentrations of growth hormone (GH) on the in vitro development of domestic dog (Canis lupus familiaris) preantral follicles in the presence or absence of follicle stimulating hormone (FSH).

METHODS

Secondary preantral follicles, isolated by microdissection, were cultured in a medium composed of αMEM with bovine serum albumin (BSA), glutamine, hypoxanthine, insulin, transferrin, selenium and ascorbic acid (αMEM(+)-control) added at different concentrations of GH (GH10 ng/ml or GH50 ng/ml) and FSH (GH10+FSH, GH50+FSH). Follicle development was evaluated based on the percentage of intact follicles, antrum formation, follicular diameter, follicular viability using fluorescent markers and estradiol production.

RESULTS

GH50 was the only treatment that maintained the same percentage of normal morphologically follicles from day 0 to day 18 of culture (P<0.05). For all treatments, except the control, follicles were viable throughout the 18 days of culture (P<0.05). GH50 supplemented with FSH (GH50+FSH) resulted in the highest average follicular diameter (P<0.05) from day 12 to 18. Follicles from both the control and the GH50+FSH treatment groups actively and increasingly secreted estradiol from day 6 to 18 of culture (P<0.05).

CONCLUSIONS

Our study demonstrates that GH benefits the maintenance of follicular morphology in a dose-dependent manner and, in association with FSH, stimulates in vitro follicular growth and estradiol production.

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.

In vitro development of bovine secondary follicles in two- and three-dimensional culture systems using vascular endothelial growth factor, insulin-like growth factor-1, and growth hormone

The aim of this study was to evaluate the development and estradiol production of isolated bovine secondary follicles in two-dimensional (2D, experiment 1) and three-dimensional (3D using alginate, experiment 2) long-term culture systems in the absence (control group; only α-MEM(+)) or presence of vascular endothelial growth factor (VEGF), insulin-like growth factor-1, or GH alone, or a combination of all. A total of 363 isolated secondary follicles were cultured individually for 32 days at 38.5 °C in 5% CO2 in a humidified incubator with addition of medium (5 μL) every other day. In 2D culture system, follicular growth and antrum formation rates were higher (P < 0.05) in VEGF treatment compared with the other treatments. In 3D culture system, only estradiol concentration was greater (P < 0.05) in the GH than in the control group, whereas the other end points were similar (P > 0.05). In summary, this study demonstrated that the benefits of using a certain type of medium supplement depended on the culture system (2D vs. 3D). Vascular endothelial growth factor was an effective supplement for the in vitro culture of bovine secondary follicles when the 2D culture system was used, whereas GH only affected estradiol production using the 3D culture system. This study sheds light on advancements in methodology to facilitate subsequent studies on bovine preantral follicle development.

Effect of morphological integrity, period, and type of culture system on the in vitro development of isolated caprine preantral follicles

The aims of this study were the following: (1) to define an optimal period for the IVC of isolated caprine preantral follicles, (2) to verify the relationship between follicular morphology (intact, extruded, and degenerate follicles) and estradiol production, and (3) to evaluate the effects of the bidimensional (2D) and three-dimensional (3D) culture systems on the in vitro development of caprine preantral follicles. Three experiments were performed. In experiments 1 and 2, the isolated secondary follicles were cultured for 18, 24, and 30 days or 30, 36, and 42 days, respectively. In experiment 3, the optimal culture period from experiment 2 was used for 2D and 3D culture systems. After culture, the oocytes were submitted to IVM. The morphological integrity, antral cavity formation rates, follicular diameter, presence of healthy, grown oocytes (≥110 μm), rates of resumption of meiosis, and estradiol concentrations were evaluated. In experiment 1, the percentage of oocytes that resumed meiosis was higher in oocytes cultured for 30 days (48.84%) than in oocytes cultured for 18 and 24 days (15% and 20.93%, respectively). In experiment 2, the percentage of oocytes that resumed meiosis was significantly higher in oocytes cultured for 30 and 36 days (47.5% and 50%, respectively) than in oocytes cultured for 42 days (20%). The estradiol concentrations on Day 12 of culture were similar for normal and extruded follicles and higher than those observed in degenerate follicles at the end of the culture period. In conclusion, the 36-day culture period resulted in the highest rates of meiosis resumption. In addition, because the loss of follicular integrity affects the patterns of estradiol production, follicular integrity is a good predictor of follicular quality.

Presence of growth hormone receptor (GH-R) mRNA and protein in goat ovarian follicles and improvement of in vitro preantral follicle survival and development with GH

This study aimed to demonstrate the expression of growth hormone receptor (GH-R) mRNA and protein in goat ovarian follicles in order to investigate the effects of GH on the survival and development of preantral follicles. The ovaries were processed for the isolation of follicles to study GH-R mRNA expression or to localization of GH-R by immunohistochemical analysis. Pieces of ovarian cortex were cultured for 7 days in minimum essential medium(+) (MEM(+)) in the presence or absence of GH at different concentrations (1, 10, 50, 100, and 200 ng/mL). High expression levels of GH-R mRNA were observed in granulosa/theca cells from large antral follicles. However, preantral follicles do not express mRNA for GH-R. Immunohistochemistry demonstrated that the GH-R protein was expressed in the oocytes/granulosa cells of antral follicles, but any protein expression was observed in preantral follicles. The highest (P < 0.05) rate of normal follicles and intermediate follicles was observed after 7 days in MEM(+) plus 10 ng/mL GH (70%). In conclusion, GH-R mRNA and protein are expressed in caprine antral follicles, but not in preantral follicles. Moreover, GH maintains the survival of goat preantral follicles and promotes the development of primordial follicles.

Effect of sequential medium on in vitro culture of goat ovarian cortical tissue

A sequential medium was evaluated on the survival, activation and growth rates of caprine preantral follicles submitted to a long-term culture period, aiming to establish an ideal in vitro culture system. Ovarian fragments were cultured for 16 days in α-MEM(+) alone or supplemented with hormones (GH and/or FSH) added sequentially on different days of culture. Ovarian fragments were cultured in the first (days 0-8) and second (days 8-16) halves of the culture period, generating 10 treatments: α-MEM(+)/α-MEM(+), FSH/FSH, FSH/GH, FSH/FSH+GH, GH/GH, GH/FSH, GH/FSH+GH, FSH+GH/FSH+GH, FSH+GH/FSH and FSH+GH/GH. Follicle morphology, viability and ultrastructure were analyzed. After day 1 of culture, FSH treatments maintained the percentage of normal follicles similar to the fresh control. At day 16 of culture, the treatment FSH/GH showed the highest (P<0.05) percentage of normal follicles. The ultrastructure of follicles was preserved in the fresh control and FSH/GH treatment. Follicles cultured with FSH/GH had a higher (P<0.05) viability than α-MEM(+); however the viability was lower (P<0.05) when compared to the fresh control. The FSH/GH treatment showed the highest (P<0.05) percentage of follicular activation and secondary follicle formation and produced the largest (P<0.05) mean follicular diameter after 16 days of culture. In conclusion, a sequential medium supplemented with FSH followed by GH during a long-term culture maintains the survival, viability and ultrastructure of goat preantral follicles, and promotes activation and secondary follicles.

Local expression and distribution of growth hormone and growth hormone receptor in the chicken ovary: effects of GH on steroidogenesis in cultured follicular granulosa cells

Preovulatory follicular development (PFD) is mainly regulated by gonadotropins (FSH, LH) and steroids, although other intraovarian factors are also involved. We analyzed the local expression of growth hormone (GH) in the hen ovary and the role that this hormone may play on the regulation of steroidogenesis in granulosa cells (GCs). Ovarian follicles from sexually mature hens were studied at different developmental stages. Both GH mRNA (by in situ hybridization) and protein (by immunohistochemistry) were expressed mainly in the GCs, and to a lesser extent in the theca cells of the follicular wall. Sequence of a GH cDNA 690-bp fragment obtained from the follicular wall was identical to that obtained from the pituitary. The growth hormone receptor (GHR) mRNA was also expressed in the follicles. Nine GH variants were observed by SDS-PAGE and Western blotting, but the main isoform showed a MW of 17 kDa, at all developmental stages. Addition of GH (0.1, 1, 10 nM) stimulated the synthesis of progesterone (P4) in primary GCs cultures in a dose-dependent manner (1.5, 2.9, 5.4 times, respectively). GH also stimulated the expression of cholesterol side-chain cleavage enzyme (cytochrome P450scc) mRNA, a rate-limiting enzyme during P4 synthesis (2.9, 4.6, 4.9 times, respectively), whereas the synthesis of 3β-hydroxysteroid dehydrogenase (3β-HSD) mRNA (a constitutive enzyme) was not changed. Both GH and GHR were co-expressed in GCs cultures. The locally expressed GH present in concentrated (4×, 6×, 8×) conditioned media obtained from ovarian GC cultures stimulated P4 production (1.2, 2.2, 4.4 times, respectively) in additional fresh cultured GCs, and this effect disappeared when the conditioned media were treated with antiserum against GH. These data suggest that locally produced GH may modulate follicular development through autocrine/paracrine effects in the chicken ovary.

Ultrastructure of isolated mouse ovarian follicles cultured in vitro

BACKGROUND

In vitro maturation of ovarian follicles, in combination with cryopreservation, might be a valuable method for preserving and/or restoring fertility in mammals with impaired reproductive function. Several culture systems capable of sustaining mammalian follicle growth in vitro have been developed and many studies exist on factors influencing the development of in vitro grown oocytes. However, a very few reports concern the ultrastructural morphology of in vitro grown follicles.

METHODS

The present study was designed to evaluate, by transmission and scanning electron microscopy, the ultrastructural features of isolated mouse preantral follicles cultured in vitro for 6 days in a standard medium containing fetal calf serum (FCS). The culture was supplemented or not with FSH.

RESULTS

The follicles cultured in FCS alone, without FSH supplementation (FCS follicles), did not form the antral cavity. They displayed low differentiation (juxta-nuclear aggregates of organelles in the ooplasm, a variable amount of microvilli on the oolemma, numerous granulosa cell-oolemma contacts, signs of degeneration in granulosa cell compartment). Eighty (80)% of FSH-treated follicles formed the antral cavity (FSH antral follicles). These follicles showed various ultrastructural markers of maturity (spreading of organelles in ooplasm, abundant microvilli on the oolemma, scarce granulosa cell-oolemma contacts, granulosa cell proliferation). Areas of detachment of the innermost granulosa cell layer from the oocyte were also found, along with a diffuse granulosa cell loosening compatible with the antral formation. Theca cells showed an immature morphology for the stage reached. Twenty (20)% of FSH-treated follicles did not develop the antral cavity (FSH non-antral follicles) and displayed morphological differentiation features intermediate between those shown by FCS and FSH antral follicles (spreading of organelles in the ooplasm, variable amount of microvilli, scattered granulosa cell-oolemma contacts, signs of degeneration in granulosa cell compartment).

CONCLUSIONS

It is concluded that FSH supports the in vitro growth of follicles, but the presence of a diffuse structural granulosa cell-oocyte uncoupling and the absence of theca development unveil the incomplete efficiency of the system. The present study contributes to explain, from a morphological point of view, the effects of culture conditions on the development of mouse in vitro grown follicles and to highlight the necessity of maintaining efficient intercellular communications to obtain large numbers of fully-grown mature germ cells.

Stability of housekeeping genes and expression of locally produced growth factors and hormone receptors in goat preantral follicles

The aim of the present study was to investigate the stability of six housekeeping genes, and the relative expression of growth factors (EGF, GDF-9, BMP-15, VEGF, FGF-2, BMP-6, IGF-1 and KL) and hormone receptors (FSH, LH and GH) in goat preantral follicles. To evaluate to stability of housekeeping genes micro-dissected fresh follicles (150–200 μm) as well as follicles that have been in vitro cultured for 12 days were used. In addition, isolated fresh follicles were used to compare expression of various growth factors and hormone receptors before culture. Both fresh and cultured follicles were subjected to total RNA extraction and synthesis of cDNA. After amplification of cDNA by real-time PCR, the geNorm software program was used to evaluate the stability of glyceraldehyde-2-phosphate dehydrogenase (GAPDH), β-tubulin, β-actin, phosphoglycerokinase (PGK), 18S rRNA, ubiquitin (UBQ) and ribosomal protein 19 (RPL-19). In addition, follicular steady-state levels of mRNA from the various growth factors under study were compared. Results demonstrated that, in goat preantral follicles, UBQ and β-actin were the most suitable reference genes and thus could be used as parameters to normalize data from future in vitro studies. In contrast, 18S RNA appeared the least stable gene among the tested housekeeping genes. Analysis of mRNA for several hypophyseal hormone receptors in fresh preantral follicles showed significantly higher FSH-R mRNA levels than those of LH-R and GH-R, and no difference between GH-R and LH-R mRNA levels. In regard growth factor mRNA expression in goat preantral follicles, EGF mRNA levels appeared significantly lower than those of the other studied growth factors. Increasingly higher relative mRNA levels were observed for GDF-9, BMP-15, BMP-6, FGF-2, VEGF, Kl and IGF-1, successively. In conclusion, UBQ and β-actin are the most stable housekeeping genes in fresh and 12-days cultured caprine preantral follicles. Furthermore, in fresh follicles, high levels of FSH-R mRNA are detected while among eight growth factors, IGF-1 is the most highly expressed and EGF the weakest expressed compound.

The effect of growth hormone on ovarian follicular response and oocyte nuclear maturation in young and aged mice

The aim of this study was to investigate the possible effects of recombinant human growth hormone (rhGH) on the ovarian follicle numbers and the nuclear maturity status of ovulated oocytes. Aged and young Balb-C mice were randomly divided into three groups: (i) control, (ii) stimulated with follicle stimulating hormone (FSH) and (iii) stimulated with FSH+rhGH. Ovaries were collected for histological and morphometric investigations. For the determination of nuclear maturation of ovulated oocytes, additional aged and young mice were randomly divided into two groups: (i) stimulated with FSH and (ii) stimulated with FSH+rhGH. In young mice, developing ovarian follicle numbers were significantly higher with rhGH; while in aged mice, there was no statistically significant difference between groups. In young mice co-stimulated with FSH and rhGH, atretic follicle numbers were significantly higher. In aged mice, atretic follicle numbers significantly decreased with FSH while there was a slight decrease with rhGH and this was not significant. The percentage of metaphase-II oocytes were significantly higher in both young and aged mice groups co-stimulated with FSH and rhGH. In conclusion, co-treatment with FSH and rhGH for ovarian stimulation in older mice appears to cause a slight decrease in the number of atretic follicles and thus improves the collection of high numbers of mature, fertilizable oocytes.

Expression and localization of growth hormone and its receptors in the chicken ovary during sexual maturation

Roles of pituitary growth hormone (GH) in female reproduction are well established. Autocrine and/or paracrine actions of GH in the mammalian ovary have additionally been proposed, although whether the ovary is an extra-pituitary site of GH expression in the laying hen is uncertain. This possibility has therefore been assessed in the ovaries of Hy-Line hens before (between 10-16 weeks of age) and after (week 17) the onset of egg laying. Reverse transcription/polymerase chain reaction (RT-PCR) analysis has consistently detected a full-length (690 bp) pituitary GH cDNA in ovarian stroma from 10 weeks of age, although GH expression is far lower than that in the pituitary gland or hypothalamus. GH mRNA is also present in small (>1-4 mm diameter) follicles after their ontogenetic appearance at 14 weeks of age and in all other developing follicles after 16 weeks of age (>4-30 mm diameter). Immunoreactivity for GH is similarly present in the ovarian stroma from 10 weeks of age and in small (<4 mm diameter) and large (>4-30 mm) follicles from 14 and 16 weeks of age, respectively. The relative intensity of GH staining in the ovarian follicles is consistently greater in the granulosa cells than in the thecal cells and is comparable with that in the follicular epithelium. A 321-bp fragment of GH receptor (GHR) cDNA, coding for the intracellular domain of the receptor, has also been detected by RT-PCR in the ovary and is present in stromal tissue by 10 weeks of age, in small follicles (<4 mm diameter) by 14 weeks of age, and in larger follicles (>4-30 mm diameter) from 16 weeks. GHR immunoreactivity has similarly been detected, like GH, in the developing ovary and in all follicles and is more intense in granulosa cells than in the theca interna or externa. The expression and location of the GH gene therefore parallels that of the GHR gene during ovarian development in the laying hen, as does the appearance of GH and GHR immunoreactivity. These results support the possibility that GH has autocrine and/or paracrine actions in ovarian function prior to and after the onset of lay in hens.

Endocrine and ovarian response after a 2-day controlled suckling and eCG treatment in lactating rabbit does

Synchronization methods are used to obtain higher fertility when artificial insemination (AI) is applied to lactating rabbit does. The most common methods are eCG administration or temporary doe-litter separation. Nevertheless, drawbacks have been reported, such as negative side effects of hormonal treatment in the doe and low litter growth due to absence of suckling, respectively. Recently, improved reproductive performance (without visible consequences on young rabbit growth), has been obtained by applying a 2-day controlled nursing method before AI, by allowing for a 10 min nursing of the litter 24 h of separation. The present study was undertaken to examine the pituitary (PRL, LH, FSH) and the ovarian response (follicle size and number) to those methods. A total of 442 lactating does inseminated on day 11 post-partum were distributed in three experimental groups: 2CN (closing of nest box on day 9, controlled nursing on days 10 and 11), eCG (20 IU administered on day 9 post-partum) and CONTROL (untreated). Blood samples were obtained from 10 does per group at 48, 24 and 0 h before AI, and 1h after AI. Both 2CN and eCG treatments similarly improved sexual receptivity (76.3, 77.5 and 58.2%, respectively; P<0.001) and fertility (63.1, 64.1 and 48.4%, respectively; P<0.05) in lactating does, compared to the CONTROL group. Similar plasma FSH levels in all groups of does and sampling times were observed. Due to the absence of suckling, plasma concentration of PRL on day 10 post-partum in the 2CN group was lower than in the CONTROL group (P<0.05); this endocrine change in PRL levels could explain the better reproductive performances obtained with 2CN treatment. At 1h after exogenous administration of GnRH (at the moment of AI) a high LH response was observed in all groups (P<0.001). Ovaries from 20 rabbits treated in the same way but uninseminated (2CN, n=10; eCG, n=5; CONTROL, n=5 does) were obtained on day 11 post-partum in order to check the morphometric status (weight, width and height) and to make histological and immunohistochemical studies to detect growth hormone receptor (GH-R). As a result, synchronization methods did not show any significant difference in relation to the CONTROL group. However, a small increase in the number of primary follicles was evidenced in the 2CN group with respect to the eCG group, similarly to the CONTROL group (23.0+/-3.7, 9.4+/-4.9 and 14.8+/-4.92 primary follicles, respectively; P=0.1). GH-R immunostaining-presence was more evident in the 2CN and the eCG groups, including primordial follicles and oocytes themselves. Thus, there could have been some direct effects of GH on follicular development, as described in other species. Some ovarian parameters described open new ways to study intra-ovarian mechanism of follicular development in the post-partum period of rabbit does.

Effects of gonadotrophins, growth hormone, and activin A on enzymatically isolated follicle growth, oocyte chromatin organization, and steroid secretion

So far, standard follicle culture systems can produce blastocyst from less than 40% of the in vitro matured oocytes compared to over 70% in the in vivo counterpart. Because the capacity for embryonic development is strictly associated with the terminal stage of oocyte growth, the nuclear maturity status of the in vitro grown oocyte was the subject of this study. Mouse early preantral follicles (100-130 microm) and early antral follicles (170-200 microm) isolated enzymatically were cultured for 12 and 4 days, respectively, in a collagen-free dish. The serum-based media were supplemented with either 100 mIU/ml FSH (FSH only); 100 mIU/ml FSH + 10 mIU/ml LH (FSH-LH); 100 mIU/ml FSH + 1 mIU/ml GH (FSH-GH) or 100 mIU/ml FSH + 100 ng/ml activin A (FSH-AA). Follicle survival was highest in follicle stimulating hormone (FSH)-AA group in both cultured preantral (91.8%) and antral follicles (82.7%). Survival rates in the other groups ranged between 48% (FSH only, preantral follicle culture) and 78.7% (FSH only, antral follicle culture). Estradiol and progesterone were undetectable in medium lacking gonadotrophins while AA supplementation in synergy with FSH caused increased estradiol secretion and a simultaneously lowered progesterone secretion. Chromatin configuration of oocytes from surviving follicles at the end of culture revealed that there were twice more developmentally incompetent non-surrounded nucleolus (NSN) oocytes (>65%) than the competent surrounded nucleolus (SN) oocytes (<34%). We conclude that the present standard follicle culture system does not produce optimum proportion of developmentally competent oocytes.

Reduced recruitment and survival of primordial and growing follicles in GH receptor-deficient mice

GH influences female fertility. The goal of the present study was to obtain more insight into the effect of loss of GH signalling, as observed in humans suffering from Laron syndrome, on ovarian function. Therefore, serial paraffin sections of ovaries of untreated and IGF-I-treated female GH receptor knock-out (GHR/GHBP-KO) mice were examined to determine the follicular reserve and the percentage of follicular atresia in each ovary. Our observations demonstrate that the amount of primordial follicles was significantly elevated in GHR/GHBP-KO mice, while the numbers of primary, preantral and antral follicles were lower compared with wild-type values. The reduced number of healthy growing follicles in GHR/GHBP-KO mice was accompanied by a significant increase in the percentage of atretic follicles. IGF-I treatment of GHR/GHBP-KO mice for 14 days resulted in a reduced number of primordial follicles, an increased number of healthy antral follicles, and a decreased percentage of atretic follicles. The results of the present study suggest that GH may play a role, either directly or indirectly, via for instance IGF-I, in the recruitment of primordial follicles into the growing pool. Furthermore, GH seems to protect antral follicles, directly or indirectly from undergoing atresia.

Impact of various endocrine and paracrine factors on in vitro culture of preantral follicles in rodents

Folliculogenesis is a complex process regulated by various paracrine and autocrine factors. In vitro growth systems of primordial and preantral follicles have been developed for future use of immature oocytes, as sources of fertilizable oocytes and for studying follicular growth and oocyte maturation mechanisms. Rodents were often chosen for in vitro follicular culture research and a lot of factors implicated in folliculogenesis have been identified using this model. To date, the mouse is the only species in which the whole process of follicular growth, oocyte maturation, fertilization and embryo transfer into recipient females was successfully performed. However, the efficiency of in vitro culture systems must still be considerably improved. Within the follicle, numerous events affect cell proliferation and the acquisition of oocyte developmental competency in vitro, including interactions between the follicular cells and the oocyte, and the composition of the culture medium. Effects of the acting factors depend on the stage of follicle development, the culture system used and the species. This paper reviews the action of endocrine, paracrine factors and other components of culture medium on in vitro growth of preantral follicles in rodents.

Chronic somatostatin treatment affects pituitary gonadotrophs, ovaries and onset of puberty in rats

The effects of chronic somatostatin (SRIH-14) treatment on the pituitary gonadotrophs (FSH and LH cells) and ovaries of female Wistar rats were examined. Females were given 20 microg/100 g b.w. twice per day from the immature (23rd day) till the adult period of life (71st day). The onset of puberty was determined by daily examination for vaginal opening. The peroxidase-antiperoxidase immunocytochemical procedure was used to study the gonadotrophs. Changes in the number per unit area (mm2), cell volume and volume densities of LH- and FSH-immunoreactive cells were evaluated by morphometry and stereology. Ovaries were analysed by simple point counting of follicles and corpora lutea (CL). Follicles were divided by size according to the classification of Gaytán and Osman. The mitotic indexes of granulosa and theca cells in the follicles were estimated at all stages of folliculogenesis. The number, volume and the volume density of FSH- and LH-immunoreactive cells decreased after chronic SRIH-14 treatment, particularly the latter. In the ovary, SRIH-14 treatment decreased the number of healthy follicles at all phases of folliculogenesis, lowered the mitotic indexes of granulosa and theca cells but increased the number of atretic follicles. Healthy CL were fewer in number, while regressive CL were increased. Vaginal opening occurred at a later age in treated females. It can be concluded that chronic SRIH-14 treatment markedly inhibited LH cells and to a lesser extent FSH cells. In the ovary SRIH-14 inhibited folliculogenesis, enhanced atretic processes and lowered proliferative activity of granulosa and theca cells. It also delayed puberty onset.

The early stages of follicular development: activation of primordial follicles and growth of preantral follicles

Although enormous progress has been made in understanding the events and regulation of the later stages of ovarian follicular development, the early stages of development, to a large extent and particularly in large mammals, remain a mystery. Mechanisms that regulate the initiation of follicular growth (follicle activation) and the ensuing growth and differentiation of preantral follicles are of considerable interest, since their elucidation is a prerequisite to use of the primordial pool to enhance reproductive efficiency in domestic animals, humans, and endangered species. This review is an attempt to summarize the approaches that have been taken to further this goal and the results thus far of these efforts. Preantral follicular development can be divided into three stages: activation of primordial follicles, the primary to secondary follicle transition, and the development of secondary follicles to the periantral stage. The activation of primordial follicles in vitro has been achieved thus far in rodents, cattle, and primates, where it occurs spontaneously without the addition of growth factors or hormones. The ovaries of rodents are small enough to be cultured intact and, in that experimental situation, some follicles activate, while many remain in the resting pool, and the addition of specific factors can increase or decrease the number of follicles that leave the resting pool in vitro. In contrast, follicular activation in cattle and primates has been studied by culturing small pieces of the ovarian cortex, rich in primordial follicles, and the great majority of the primordial follicles activate in that situation, suggesting the importance of inhibitory factors to the normal, gradual exit of follicles from the resting pool. In cultured rodent ovaries, follicles appear to pass easily and spontaneously from the primary to the secondary stage, whereas few of the activated follicles in cultured cortical pieces from cattle or primates progress from the primary to the secondary stage. Understanding the requirements for the primary to secondary transition is critical for growing follicles activated in vitro to the late preantral and antral stages. In contrast, the requirements for the continued growth of larger preantral follicles, which can be isolated for in vitro studies, have been extensively explored in rodents and to a lesser extent in domestic species. A number of hormones and factors have been implicated and will be discussed. Taken together, the results highlight the need for a better understanding of the earliest stages of follicular development in domestic ruminants, particularly follicle activation and the primary to secondary follicle transition.

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.

IGF-1 in gynaecology and obstetrics: update 2002

Recent discoveries on endocrine, paracrine and autocrine involvement of insulin-like growth factor-1 (IGF-1) in the proliferation of many tissues raised the attention of its role in reproduction and in the growth of various cancers as well as of benign proliferations. The intention of this article is to focus on IGF-1 in the field of gynaecology. Perimenopausal women who exhibit high IGF-1 and low IGF binding protein (IGFBP) levels, like IGFBG-3, have an increased risk of developing breast cancer. A higher risk for cervical, ovarian and endometrial cancer is related to high IGF-1 levels in post- and premenopausal women. It has been shown that myomas, by far the most common benign uterine tumor in women, grow in the presence of IGF-1, in vitro as well as in vivo. Studies show that IGF-1 is involved in the differentiation of various reproductive tissues, like endometrium and ovarian tissues. Patients suffering from polycystic ovary syndrome (PCO) frequently show insulin resistance accompanied by an increase of IGF-1 in plasma. Plasma IGF-1 levels are higher in cases of severe endometriosis, however, in endometriosis and in PCO IGF levels locally in the endometrium are reduced, what might explain infertility. Recently, it was shown that IGF facilitates the implantation of the human embryo in the endometrium during IVF. Implantation is a paradox where different immune systems have to collaborate to make implantation and survival of the pregnancy possible. IGF seems to be the starter molecule so that the two epithelia can fuse. A disturbance can result in complications during pregnancy i.e. spontaneous miscarriage, preeclampsia as well as defects of the embryo. Therefore, IGF is a useful marker in successful pregnancy as well. A better mechanistic understanding of IGF-1 action on the cellular level not only provides more elegant mechanistic explanations for the scientist, but the practitioner might find it interesting to utilize its diagnostic potential as a marker for various diseases. The relation between systemic IGF levels and local tissue IGF-1 levels has not yet been determined for all conditions.

Effects of multiple somatostatin treatment on rat gonadotrophic cells and ovaries

The effect of multiple somatostatin (SRIH-14) treatment on the pituitary gonadotrophs, follicle stimulating harmone (FSH) and luteinizing harmone (LH), and ovaries of adult female Wistar rats was examined. Females received two 20 microg/100 g body wt. doses daily subcutaneously, for five consecutive days. FSH and LH cells were studied using a peroxidase-antiperoxidase immunocytochemical procedure. Morphometry and stereology were used to evaluate changes in the number per unit area (mm2), cell volume and volume densities of LH- and FSH-immunoreactive cells. Ovaries were analysed by simple point counting of follicles and corpora lutea. Follicles were divided by size according to the classification of Gaytán and Osman. Morphometric and stereological analysis of the pituitary showed that the number, volume and the volume density of FSH- and LH-immunoreactive cells were decreased after multiple SRIH-14 treatment, particularly in the latter. In the ovary, SRIH-14 induced decreases in the number of healthy follicles in all phases of folliculogenesis and corpora lutea, but the large antral follicle stage was most affected. The number of atretic follicles was increased. It can be concluded that multiple SRIH-14 treatment markedly inhibited LH cells, but affected FSH cells as well. In the ovary, SRIH- 14 acted by inhibiting folliculogenesis and enhancing atretic processes.

In vitro follicle growth: achievements in mammalian species

The exact mechanisms regulating in vivo folliculogenesis in mammalians have only been partly unravelled. Some processes, such as the initiation of growth of primordial follicles are still poorly understood. This increases the difficulty to culture follicles in vitro as the primordial follicles will be the ultimate starting material for culture. There are important species differences in regulation and timing of maturation, which makes it difficult to transpose techniques. Only in the mouse model, live pups were born when primordial or early preantral follicles were cultured entirely in vitro. Although no systems are as yet permitting complete in vitro culture of early follicle stages in large animals or humans, parts of folliculogenesis have been successfully reproduced in vitro. This review summarizes achievements of the last years in follicle culturing starting off at several stages of development. Future applications of in vitro follicle culture include fertility preservation for humans, preservation of rare animal species and creation of oocyte banks for research.