New observations on the physiology of menstruation

Abstract

Endometrium was studies histologically, histochemically, and ultrastructurally in a series of biopsies taken from 3 normal, ovulating patients on Days 1-9 of the cycle. The occurrence of ovulation and the adequacy of progesterone were determined by radioimmunoassay. The most striking feature of menstruating endometrium was its vigorous attempt to survive. This was manifested by lysosomal activity, lipid accumulation, expulsion of glycoproteins, and the uptake of stromal debris by epithelial cells for passage to the uterine cavity. Regression, rather than cell death, was the chief event of menstruation. While some cells of the spongiosa underwent necrosis, the vast majority remained viable and underwent remodeling to participate in the new cycle. These studies may lead to further understanding of the process of menstruation and the pathophysiology of anovulatory bleeding and irregular shedding of the endometrium.

PIP: To understand the differences between menstruation and the pathophysiology of anovulatory bleeding and irregular shedding of the endometrium, a series of biopsies were taken from 3 normal ovulating patients on Days 1-9 of the cycle. Occurrence of ovulation and the adequacy of progesterone were determined by radioimmunoassay. Findings are discussed and illustrated in detail. The most striking feature of the menstruating endometrium was its vigorous attempt to survive. Regression, rather than cell death, was the chief characteristics and was accompanied by lysosomal activity, lipid accumulation, expulsion of glycoproteins, and uptake of stromal debris by epithelial cells for passage to the uterine cavity. While some cells of the spongiosa underwent necrosis, electron microscopy showed that most of the cells r and participated in a new cycle. These studies dispel the theory that inadequate lymphatic drainage causes tissue destruction. There is no accumulation of catabolic products. The only cells which die or become detached from the endometrium are from the compact and upper spongy layers. Some were sufficiently viable to grow on surfaces where they could implant and receive nourishment. However, if they were stimulated to secretory exhaustion by an oral contraceptive or deprived of physiologic estrogen stimulation by gonadotropin inhibitors, their survival would be limited to the life expectancy of the cell. Thus, endometriosis caused by retrograde menstruation would respond to oral contraceptives and gonadotropin inhibitors while endometriosis from metaplasia of the pelvic peritoneum to a Mullerian type of epithelium and stroma would be adversely affected by progestins. Endometriosis with a basalis endometrium must be treated by conservative surgery and/or hysterectomy and extirpation of the ovaries. No findings supported the theory of menstrual toxin. It is probable that some of the presently accepted concepts of menstruation developed from the study of anovulatory or inadequate ovulatory endometrium which is associated with varying degrees of necrosis and sloughing to the basalis.