The Effects of Selective Withdrawal of FSH or LH on Spermatogenesis in the Immature Rat

The effects of antisera specific to rat follicle stimulating hormone (FSH) and sheep luteinizing hormone (LH) on spermatogenesis were studied in 20-day-old rats. The antisera to rat FSH binds only with iodine-125 FSH while the sheep anti-LH serum cross-reacts with rat LH. Anti-LH serum administered over a 14-day period caused an 80% reduction in testes weight and a considerable reduction in the weights of the epididymides ventral prostate and seminal vesicles. A reduction in the size of the Leydig cells of the diameter of the seminiferous tubules and in the number of germ cells was observed. Serum testosterone levels were dramatically reduced (113 + or -6 pg/ml compared with 616 + or -138 pg/ml in controls). Anti-FSH serum treatment decreased testes weight by about 50% but did not markedly reduce accessory organ weights or serum testosterone levels. Although the Leydig cells appeared normal the tubule diameter and the number of spermatocytes and spermatids were reduced below control values. It appears that anti-FSH serum inhibits spermatogenesis in the immature rat without affecting serum testosterone levels.