Discussion [of lysosome function in normal endometrium and endometrium exposed to contraceptive steroids].

Lysosomes differ as to types locations and function in the endometrium. Stromal lysosomes are usually found in endometrial granulocytes which are bound to lysosomes and released by a drop in progesterone thereby increasing permeability of lysosomal membranes. Normal menstrual shedding results if the events occur evenly. If the occurence is focal as in oral contraceptive use breakthrough bleeding occurs. Vascular change many not necessarily cause endometrial bleeding. Tissue dissolution occurs first brought about either by 1) release of lysosomes and granules from endometrial granulocytes causing tissue dissociation as in normal menstruation or 2) anovulatory tissue necrosis causing shrinkage of tissue and vessels. IUD-associated abnormal bleeding has been related at the ultrastructural level with vessel breaks and diapedesis. The relation of lysosome function to the onset of menstrual bleeding is not well understood due to lack of data and research on the subject. There has also never been a satisfactory histochemical study at the ultrastructural level of the endometrium of women exposed to long-term contraceptive steroids in appropriate dosages. Further research should be done on the histochemistry of the vascular structure in the endometrium in relation to lysosomal enzymes.