[Enzyme histochemical studies on the rat adrenal cortex, ovary, uterus and vagina following chlormadinone acetate administration, especially cholinesterase activity in myometrium and endometrium].

1. Female albino rats were treated with a total of 28 mg of chlormadinone acetate (CMA) for 28 days. In the adrenal cortex, the ovary, the vagina, and the uterus the activities of 3-beta-ol-steroiddehydrogenase, of dl-beta-OH-butric acid dehydrogenase, of alcaline and acid phosphatases, of DPN-diaphorase, of ATP-ase, and of non-specific esterases do not differ from untreated controls. 2. In the external muscle layer of the myometrium strong cholinesterase (ChE) activity was induced by C.M.A. A corresponding high ChE activity is normally found in immature rats or in estrus. 3. Furthermore, by treatment with CMA, ChE activity was induced in the tubular glands of the endometrium. This activity is found in the small parts of glomerate glandular terminals only but not in the rest of the glandular epithelium, nor in the epithelium of the cavum. It could be demonstrated that a corresponding ChE activity normally appears in the second third of pregnancy. The ChE activity induced by CMA was considerably higher and more widespread than during normal pregnancy. 4. It is concluded that in the endometrial glands a development similar to pregnancy is initiated by CMA. But development stops at the stage of ChE activity, thus leading to accumulation of ChE active cells.