Dissociation between female sexual behavior and luteinizing hormone release in old female rats

Abstract

The relationship between lordosis behavior and LH release as measured by the response to mating or by the positive feedback response to estradiol benzoate (EB)/progesterone was studied in ovariectomized rats of three different age groups: young adult female rats (5 to 8 months old), middle age female rats (15 to 23 months old) and old female rats (over 24 months old). Middle age and old rats showed high levels of lordosis behavior regardless of the pattern of LH secretion in response to mating or the positive feedback response to EB/progesterone. The mean LH rise after mating as well as after EB/progesterone treatment in pooled middle age and old rats is significantly lower than that of young rats. A clear dissociation between lordosis behavior and LH release in middle age and old female rats suggests that they are regulated at least in part by different mechanisms.