Epidermal Thickness Following Oestrone Injections in the Mouse

Abstract

THE cyclic variation in the mitotic activity of the epidermis of the adult female mouse, which is dependent on the cyclic activity of the ovary, is accompanied by coincident cyclic variation in epidermal thickness¹. Thus, in the antero-dorsal region of the body, the highest rate of mitotic activity occurs during the proœstrous period, with the result that the epidermis is at its thickest in proœstrus and early œstrus. It has also been shown that the mitotic activity of the epidermis can be artificially stimulated by œstrone injections², and it would therefore seem probable that the same treatment would result in epidermal thickening. However, Hooker and Pfeiffer³ have reported that injections of œstradiol benzoate result in a decrease of epidermal thickness, an effect apparently due to inhibited mitotic activity. An additional analysis of the effects of œstrone injections on the rate of cell division and thickness of the epidermis has therefore been made in an attempt to throw light on the apparent contradiction.