Effects of thyroxine treatment during lactation on the testicular function of rats across different ages

Thyroid hormones are involved in the development of several tissues and organs and are essential for the normal growth and reproductive function. The aim of this study was to determine the effects of thyroid hormones on the development of testis and progression of spermatogenesis. Lactating mothers were treated with oral thyroxine (T4; 20 μg/100 g) for 20 days after parturition. The pups were decapitated at the age of 20, 40 and 60 days post partum. Neonatal hyperthyroidism resulted in a decrease in body and testis mass, an increase of free thyroxine and a decrease of testosterone concentrations in plasma of treated rats. The treatment was associated with a significant decrease of the diameter of seminiferous tubules and a slowdown in spermatogenesis, following a delay in the maturation of germ cells. We conclude that thyroid hormones affect the progression of postnatal spermatogenesis

EFFECT OF LEPTIN ON FOLLICULOGENESIS DURING DEVELOPMENT IN FEMALE WISTAR RAT

This study aims to investigate the effect of leptin on ovaries in female Wistar rat during development. Rats were divided into two groups: 30 and 60-day-old females. Experimental treated females were administrated                 8 μg/100 g body weight intraperitoneal leptin injections daily for 5 days, while controls received the same volume of saline solution. Leptin treatment resulted in a significant decrease in body weight (150.50 ± 4.02 vs 157.78 ± 3.51 g,               p 0.05). For FSH, the difference between controls and treated females was not significant in both ages (p > 0.05). Leptin appears to be involved in the regulation of body weight, folliculogenesis, the ovulatory process and luteogenesis by control of gonadotropic hormones and progesterone at the age of 60 days but not at 30 days, when leptin receptors are probably not expressed yet