Effect of gonadotropins and thyrotropin on the testes and ovaries of the newly hatched chicken.

In newly hatched male and female chickens thyrotropin (TSH) and gonadotropins (FSH, LH) were found to increase the number of spermatogonia or Sertoli cells in the seminiferous cord, and the number of granulosa cells in the ovarian follicle. The effect of gonadotropins was more pronounced than that of TSH. Regarding the overlapping effect of thyrotropin and gonadotropins, in both male and female neonatal gonads the hormones similar in structure seem to be able to substitute each other. They do not however, change each other's effect on the parenchymatous tissue (number of spermatogonia and Sertoli cells in the male, and number of follicles in the female) if they are administered one after the other.