Testicular Growth and Pubertal Onset in GH-Deficient Children Treated With Growth Hormone: A Retrospective Study

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.

Higher Prepubertal IGF-1 Concentrations Associate to Earlier Pubertal Tempo in Both Sexes

INTRODUCTION

Pubertal onset is triggered by multiple neuroendocrine interactions. The role of prepubertal IGF-1 in this process has not been explored in both sexes. Our objective was to analyze the association of prepubertal IGF-1 concentration with age at thelarche (B2) and menarche (M) in girls and age at gonadarche (G2) in boys.

METHODS

This is a longitudinal study (n = 1,196 boys and girls) within the Growth and Obesity Chilean Cohort Study (GOCS). At age ≈ 6.7 years, blood sample was taken for IGF-1. Subjects were divided into 4 groups according to the onset age of the pubertal event.

RESULTS

Higher prepubertal IGF-1 levels were observed at earlier ages of B2 (p = 0.003) and M onset (p = 0.041). A taller prepubertal height was observed at younger ages of B2 and M (p=<0.001 and 0.002, respectively). The hazard proportional regression models (HR) showed that with an increase of 1 SD in IGF-1, the HR of presenting B2 at younger ages was 1.25, and this association was maintained when adjusted for confounding variables. Similarly, the HR of presenting M at earlier ages was 1.21. This association was maintained only when adjusting for body mass index but not using further confounders. In boys, prepubertal IGF-1 showed a tendency to be significantly higher in children with earlier G2 and taller height (both p < 0.001). The HR of presenting G2 at younger ages was 1.22, and this association was maintained after adjusting for confounders.

CONCLUSIONS

Higher IGF-1 levels in mid-childhood are associated with earlier puberty onset. The role of IGF-1 in the onset of puberty requires further investigation.

Reproductive Markers of Testicular Function and Size During Puberty in Boys With and Without a History of Cryptorchidism

CONTEXT

Longitudinal data on levels of hypothalamic-pituitary-gonadal axis hormones and insulin-like growth factor I (IGF-I) during puberty in boys with a history of cryptorchidism are largely missing.

OBJECTIVE

We aimed to compare pubertal hormone levels between boys with a history of congenital cryptorchidism who experienced spontaneous testicular descent or underwent orchiopexy and boys without a history of cryptorchidism.

METHODS

This was a nested case-control study within a population-based birth cohort, with a prospective, longitudinal pubertal follow-up every 6 months (2005 to 2019). Participants were 109 Finnish boys, including boys with a history of unilateral cryptorchidism who underwent orchiopexy (n = 15), unilateral cryptorchidism who had spontaneous testicular descent (n = 15), bilateral cryptorchidism who underwent orchiopexy (n = 9), bilateral cryptorchidism who had spontaneous testicular descent (n = 7), and controls (n = 63). Serum reproductive hormone levels and testicular volumes were measured.

RESULTS

From around onset of puberty, boys with bilateral cryptorchidism who underwent orchiopexy had significantly higher follicle-stimulating hormone (FSH) and lower inhibin B levels than controls. Boys with unilateral cryptorchidism who underwent orchiopexy had significantly higher FSH than controls, whereas inhibin B levels were similar. Testosterone, luteinizing hormone, insulin-like factor 3, and IGF-I were generally similar between groups. Testicular volume of boys with unilateral or bilateral cryptorchidism who underwent orchiopexy was smaller than that of the controls from 1 year after pubertal onset (P < 0.05).

CONCLUSION

Cryptorchid boys, particularly those with bilateral cryptorchidism who underwent orchiopexy, had altered levels of serum biomarkers of Sertoli cells and germ cells and smaller testicular volumes compared with controls.

LOCAL-IGF-1 and GH application IMPROVES germ cell histology, spermatogenesis and fertility after experimental testicular torsion and detorsion

OBJECTIVE

To evaluate the impact of insulin like growth factor-1(IGF-1) and growth hormone (GH) on testis histology, spermatogenesis, and fertility in prepubertal rats exposed to 6 h of testicular torsion (TT) and detorsion.

MATERIAL-METHOD

Forty-eight male Wistar-albino rats weighing 30-70g and at 3-week age were allocated into six groups involving eight rats in each group as follows: Group 1:Sham, Group 2:Control, Group 3:Gelatin, Group 4:Local-IGF-1, 5: Local-GH, Group 6: Systemic-GH. Right testis was only exposed and sutured in the sham group, and right testes were rotated clockwise, 720°, fixed, and 6 h later, detorsion on the testis was done in groups 2-6. Unloaded gelatin, 5 μg local-IGF-1 loaded, and 2IU rhGH loaded gelatin were sutured to the right testis after detorsion in groups 3-5. In Group 6, 0.3IU/100gr/d rhGH was given for seven days via subcuticular route after detorsion. Each of the rats cohabited with two female rats five weeks later. Afterward, both right and left testes were removed. Mean diameter of seminiferous tubules (STD), mean biopsy score count of the testis (TBSC), mean percentage of haploid cells (HCP) were assessed, and fertility parameters were evaluated.

RESULTS

STD and TBSC of the ipsilateral testes were significantly reduced in control and gelatin groups when compared to sham, local-IGF-1, and local-GH groups. STD and TBSC of the ipsilateral testes of the systemic-GH group were decreased compared to the sham group. HCP of the ipsilateral testes of control, gelatin, and systemic-GH groups were significantly lower than the sham, local-IGF-1, and local-GH groups. STD, TBSC, and HCP of the contralateral testes were significantly reduced in control and gelatin groups when compared separately to sham, local-IGF-1, systemic- GH, and local-GH groups. The difference between groups regarding potency, fertility, fecundity indexes, and mean fetus numbers were not significant.

CONCLUSION

Even though there was significant and permanent histologic germ cell damage and reduced HCP in both ipsilateral and contralateral testes, experimental 6 h TT and detorsion in prepubertal rats did not have a negative impact on future fertility. Local-IGF-1and rhGH treatment improved germ cell histology and spermatogenesis in both ipsilateral and contralateral testes of prepubertal rats, subjected to 6 h of TT and detorsion.

Pubertal timing in children with Silver Russell syndrome compared to those born small for gestational age

CONTEXT

Data on pubertal timing in Silver Russell syndrome (SRS) are limited.

DESIGN AND METHODS

Retrospective observational study including twenty-three SRS patients [11p15 loss of methylation, (11p15 LOM, n=10) and maternal uniparental disomy of chromosome 7 (mUPD7, n=13)] and 21 small for gestational age (SGA). Clinical (thelarche in females; testis volume ≥ 4 ml in males; pubarche), BMI SD trend from the age of 5 to 9 years to the time of puberty, biochemical parameters of puberty onset [Luteinizing hormone (LH), 17-β-estradiol, testosterone], and bone age progression were evaluated.

RESULTS

Pubertal onset and pubarche occurred significantly earlier in children with SRS than in SGA (p 0.03 and p 0.001, respectively) and clinical signs of puberty onset occurred earlier in mUPD7 than in 11p15LOM group (p 0.003). Five SRS children experienced central precocious puberty and LH, 17-β-estradiol, testosterone were detected earlier in SRS than in SGA (p 0.01; p 0.0001). Bone age delay in SRS children was followed by rapid advancement; the delta between bone age and chronological age in SRS group became significantly higher than in SGA group at the age of 9-11 years (p 0.007). 11p15LOM patients were underweight at the age of 5 years and showed a progressive normalization of BMI that was significantly higher than in mUPD7 (p 0.04) and SGA groups (p 0.03) at puberty onset.

CONCLUSION

Timing of puberty is affected in SRS and occurred earlier in mUPD7 compared to 11p15LOM. The impact of early puberty on adult height and metabolic status deserves long-term evaluation.