Minipuberty in Male Full-term Neonates Appropriate and Small for Gestational Age and in Preterm Babies: Data from a Single Centre

INTRODUCTION: The postnatal activation of the hypothalamic-pituitary-gonadal (HPG) axis is usually known as 'minipuberty'. There are still open questions about its biological function and significance depending on sex, gestational age (GA) and birth weight (BW) with few available longitudinal data. METHODS: A single-centre, longitudinal study to quantify urinary follicle stimulating hormone (uFSH), luteinizing hormone (uLH) and testosterone (uTs) in male neonates. Neonates were enrolled and stratified into three subgroups: full-term boys appropriate for GA (FT AGA); FT boys with BW ≤3rd centile [FT small for gestational age (SGA)]; and preterm (PT) boys ≤33 weeks of GA. Urinary hormones were correlated to simultaneous auxological parameters, linear growth and external genitalia at scheduled time-points. RESULTS: Forty-six boys were recruited, with subgroup sizes FT AGA n=23, FT SGA n=11 and PT n=12. PT boys display a pulsatile pattern of urinary gonadotropins (uGns) with higher levels of uLH and a gradual increase of uTs. Testicular descent started from 29-32 weeks with the peak of uTs. During the first 12-months post-term age (PTA), FT AGA boys displayed a better linear growth (p<0.05). PT showed higher uGns levels until 3-months PTA. PT babies had higher uLH levels than FT AGA, with a peak at 7 and 30 days, during the first 90 days of life (p<0.001) and higher uTs levels. Correlation analysis between penile growth of all neonates and uTs was significant (p=0.04) but not within subgroups. DISCUSSION AND CONCLUSION: This study investigated postnatal HPG axis activation in term and PT infants. Minipuberty may involve an early window of opportunity to evaluate the functionality of the HPG axis. Further studies with a long-term follow-up are needed with a special focus on possible consequences of GA and BW

The FSHR polymorphism p.N680S mediates different response kinetics to FSH in vitro

Introduction: FSH acts on its receptor (FSHR) resulting in signal transduction activation, gene expression and steroidogenesis. The FSHR common SNP p.N680S is a marker of gonadal response in vivo. However, in vitro dose–response experiments failed to demonstrate the molecular basis thereof so far. In this study, we systematically investigated whether p.N680S mediates different kinetics of FSH response in vitro. Design: We evaluated the activation kinetics of cAMP, phERK1/2, phCREB by ELISA and western blotting in FSHR homozygous, primary, human granulosa lutein cells (hGLC-680N, -680S) stimulated by 50 nM r-FSH for up to 2 h (short-term stimulation). Following short-term stimulation the expression of target genes was evaluated by real-time PCR after 12 h, and progesterone production kinetics over 24 h. Specific inhibitors/agonists (U0126, PMA) were used in the presence and in the absence of FSH. Results: Intracellular cAMP increased within 5–10 min in hGLC-680N, reaching the plateau in about 45 min. cAMP increase was delayed in hGLC-680S, reaching the plateau in 120 min, revealing different activation kinetics (Mann–Whitney U test; P<0.05; n=4). r-FSH-dependent cAMP stimulation kinetics resulted in different ERK1/2 and CREB phosphorylation, reaching maximal levels in 5–30 min in hGLC-680N, whereas, in hGLC-680S, these were weaker and steady over 2 h (Mann–Whitney U test; P<0.05; n=3). hGLC-680N stimulation resulted in higher expression levels of AREG and StAR (Mann–Whitney U test; P<0.05; n=4) and in subsequently different progesterone production kinetics, achieving overall higher levels in hGLC-680N vs -680S (Mann–Whitney U test; P<0.05; n=3). Interestingly, the different kinetics of progesterone production between hGLC-680N and -680S were interchanged by selective phospho-ERK1/2 blockade/activation through specific inhibitor/agonist, revealing a short-term cross-talk mediated by ERK1/2. Conclusions: This study demonstrates for the first time in vitro, how FSHR p.N680S mediates different response to FSH, resulting in different kinetics of cAMP, phERK1/2 and phCREB activation, and progesterone production

FSHR polymorphism p.N680S mediates different responses to FSH in vitro

The single nucleotide polymorphism p.N680S of the follicle-stimulating hormone (FSH) receptor (FSHR) is a discrete marker of ovarian response but previous in vitro studies failed to demonstrate differences in the response to FSH between N and S carrier cells. Here we demonstrate that p.N680S mediates different kinetics of the response to FSH in vitro. Intracellular cAMP production is faster in p.N680S N than in S homozygous human granulosa cells (45 versus 90 min to achieve the plateau, respectively; Mann-Whitney's U-test; p < 0.005; n = 4). Reflecting the cAMP kinetics, phospho-ERK1/2 and -CREB activation, AREG and STARD1 gene expressions and progesterone production were qualitatively and quantitatively different in N versus S homozygous cells. Finally, the blockade of ERK pathway by U0126 abolishes the genotype-mediated different effects on gene expression and progesterone production (Mann-Whitney's U-test; p ≥ 0.005; n = 3)