[Effects of quingestanol acetate on the histology, histochemistry and ultrastructure of the endometrium].

According to studies carried out using the optical microscope and the electron microscope quingestanol acetate, which is a powerful progestagen, modified significantly the histology and the histochemistry of the endometrium. The mechanisms of transport across the cellular membranes are not changed, but probably there is competition between the oestrogens at the binding sites as a result of which the synthesis of proteins and hydrocarbons is changed. This in turn provokes the formation of aggregations of platelets in the blood vessels and cellular degeneration starting from the onset of the cycle. The contraceptive efficiency of quingestanol acetate when it is administered by itself is due to alterations in cellular biology which it brings about at the level of the endometrium as well as due to its inhibitory effect on gonadotropins.