Epidermal Mitosis in Relation to Sugar and Phosphate

Abstract

DESCRIPTIONS have been given of the diurnal mitosis cycles in the ear epidermis of the adult male mouse, and the conclusion has been reached that the form of these cycles is determined by the daily routine of activity and of rest¹. During bodily activity, the mitosis-rate is low, and during sleep and rest it is high. In extending these observations, two further important facts were noticed, namely, that excessive muscular exercise is followed by an abnormal depression of the mitosis-rate², and more recently, that the same effect can be induced by extreme cold. Since in both these situations there is a drain on the sugar reserves of the body, in the one case for muscle contraction and in the other for heat production, it was suspected that an abundance of sugar may be a critical factor in the development of a high mitosis-rate.