ABSTRACT
The aim of the study was to establish the profile of inhibit B in normal and in experimentally manipulated sertoli and germ cells by transient neonatal hypothyroidism [TNH], hemicastration and acute irradiation in prepubertal and pubertal rats. Material and After birth, pups were divided by sex and male pups were retained. For neonates designated as controls [group I] [10 rats]: mothers and litters remained untreated, received food and water adlibitum then pups of 21 days old were sham operated. Group II [Hypothyroid group]: neonates were made hypothyroid by the addition of 0.1% [wt/vol] propylthiouracil [PTU] to the mothers water immediately after birth from day 1 to day 21. Group III [hemicastrated group] [10 rats]: neonatal hemicastration was done on day 21. Group IV [irradiated group] [10 rats]: 21 day old rats were exposed to a low dose of 3 Grays of gamma ray. Serum was collected at prepuberty [4th week] and puberty [12th week] for estimation of inhibin B, follicle stimulating hormone [FSH] and testosterone levels.Semen analysis was done for pubertal rats. Inhibin B levels significantly declined at all groups II, III and IV compared to control rats aged 4 weeks. While in rats aged 12 weeks, significant increase at inhibin B level was observed at group II, while significantly declined at both groups III and IV. Comparing inhibin B levels at both age groups, there was significant decline in both control and hemicastrated rats with advancing age. While insignificant change was observed at both hypothyroid and irradiated groups. Prepubertal inhibin B level in control group correlated positively with its pubertal level, testosterone, sperm quality and pubertal testicular weight. It was negatively correlated with FSH both prepubutaly and at puberty. The study confirms the role that inhibin plays in the regulation of FSH secretion. Measurement of inhibin B prepubertally may give clinical clues about developmental deficiencies in the gonads that otherwise only become apparent around puberty or later in life