THE OVARIAN HORMONES AND SPONTANEOUS RUNNING ACTIVITY IN THE FEMALE RAT1

Abstract

The complete restoration of running activity in the ovariectomized albino rat is accomplished with rather small quantities of estrone administered in such a way that a constant source of the hormone is maintained. Estradiol benzoate in the quantities injected was less effective and supplementary injns. of progesterone were completely dispensable. It is not implied that estrone is the only estrogenic substance having this action. The amt. of activity following replacement therapy was generally proportional to the amt. shown prior to ovariectomy rather than to the amt. of hormone given. This fact, when taken in conjunction with the observation that the ovaries of the less active animals were not different from those of the more active animals, led to the belief that the character of running activity like that of the mating responses is strongly influenced by unidentified somatic factors, or at least extra-ovarian factors, rather-than by quantitative fluctuations in the amt. of available estrogenic substances. Attention is called to a number of fundamental similarities and differences between running activity and the mating response. The suggestion is made that these 2 features of the estrous behavior pattern are mediated by different mechanisms.