Luteinizing hormone in the cat. II. Mating-induced secretion.

Abstract

In cannulated female cats, LH concentrations increased within 5 min after mating and usually reached a maximum within 20 min if the animals were limited to a single copulation. The dynamics of such LH release were similar to those observed after the iv injection of gonadotropin-releasing hormone (GnRH). A second mating, 1 h after the first, resulted in a second, similar increase in concentrations of LH without evidence of a priming effect of the first mating on the LH release mechanism. When female cats were permitted to mate at their own pace, copulations were frequent during the first 2 h, with LH release being evident during the first 90 min. However, the copulatory stimulus became ineffective (or nearly so) at inducing LH release when matings continued beyond this period. In all types of cats studied (spontaneous estrous, estrogentreated, intact, and estrogen-treated castrate), the LH response to a single coitus varied considerably and was not correlated with plasma concentrations of estradiol or prog...