Effects of early treatment with antiserum to ovine follicle-stimulating hormone and luteinizing hormone on gonadal development in the rat.

Neonatal rats secrete considerable amounts of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) between 5 and 15 days of age. Antisera to LH and FSH were injected during this 11-day period in an attempt to study the importance of gonadotropins for functional development of the gonads. Autopsies at 15 days of age revealed normal ovarian follicular histology after either antiserum treatment, but antiserum to LH significantly retarded differentiation of interstitial tissue. Uterine weights were increased, and some of the serum samples showed elevated FSH levels following the antiserum treatments. The testes of antiserum-treated rats were heavier at 15 days of age, while accessory sex organ weights were unchanged. Vaginal opening after antiserum treatment was more variable than in controls, but tended to be earlier. The first appearance of penile serum was not significantly changed. Both males and females were fertile as adults. Important limitations to the use of chronic antiserum injections were found in immature rats. The antisera were present for at least 34 days after injection. The ways in which this pool of antiserum might have influenced the results are discussed.