GONADOTROPHIN PATTERNS IN MALE AND FEMALE RATS: PLASMA LH AND FSH AT VARIOUS AGES EVALUATED BY THE METHOD OF PARABIOSIS

Abstract

ABSTRACT Ventral prostates in hypophysectomized male parabiotic partners of intact animals were used to compare the amount of plasma luteinizing hormone (LH) in males and females of various ages. Ovarian weight, histology, and augmentation with chorionic gonadotrophin, in hypophysectomized androgenized females were used to estimate plasma follicle stimulating hormone (FSH) activity in intact adult males and females. In young animals, up to 50 days of age, males apparently have the same amount of plasma LH as females, but older cyclic females produced significantly heavier prostates in their hypophysectomized male partners than did males. The results are consistent with the interpretation that cyclic surges of LH added to a tonic level produced an average value higher for females than males. In contrast, males of all ages and particularly adults, have a significantly greater amount of circulating FSH than females.