Hormone Inhibition During Mini-Puberty and Testicular Function in Male Rats

The mini-pubertal period of almost six hours in neonatal male rats is thought to be an important stage in sexual development.

The aim of this study was to investigate the effect of hormone inhibition during mini-puberty on testicular function in male rats.

We measured serum testosterone (T), luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels in male rats at different time points after birth by enzyme linked immunosorbent assay (ELISA) and established a "no mini-puberty" model by ether inhalation. The mRNA expression levels of testicular androgen receptor (AR), insulin-like growth factor 3 (INSL3), anti-Mullerian hormone (AMH), and ghrelin were determined by real-time polymerase chain reaction (PCR) assays on postnatal days 45 and 75. Testicular tissue biopsies were stained with hematoxylin and eosin (H & E) and the structure, number and maturity of testis cells (including spermatogenic, Sertoli, and Leydig cells) were observed under microscopy at the same time.

Serum T and LH levels peaked at two hours after birth, while FSH peaked at hour 0, and bilateral testicular weight peaked at four hours after birth. The rats that underwent ether inhalation five minutes after birth had markedly reduced serum hormone levels. The mini-puberty model group revealed visible morphologic alterations in the tests on postnatal day 45. Then, on postnatal day 75, the mRNA expression level of AMH significantly decreased (P < 0.05) in the same group.

The inhibition of mini-puberty period in male rats was demonstrated to have an effect on their testicular function to some extent.