Regulation of uterine activity during gestation and parturition in rabbits and rats.

Abstract

Uterine muscular activity is influenced by ovarian steroid hormones, by nervous activity, and by endogenous, humoral or locally produced, uterus-activating agents such as the neurohypophyseal peptides, the prostaglandins, and various biogenic amines. Purely physical factors, such as stretch, also play a part in the regulation of myometrial function. While the neural control of uterine function is more intimately linked to uterine vascular supply than to its muscular elements, at least in rats and rabbits, the hormonal factors exert a profound influence directly on the contractile components of the uterus. However, in spite of much progress in recent years in the understanding of the mechanism of action of steroid hormones, the integration of biochemical events at the molecular level into various contractile responses at the tissue level remains to be elucidated. The possible interrelationship between endocrine factors and the nervous system in integrating the total activity of the whole organ has also to be clarified, but all evidence points to the hormonal and humoral agents as the dominating factors in the regulation of uterine contractility.