STRESS AND EPIDERMAL MITOTIC ACTIVITY.

Abstract

The effects of stress, induced by overcrowding adult male mice, have been examined in relation to adrenal size and to epidermal mitotic activity. After 3 weeks the size (expressed as the maximum sectional area) of the adrenal medulla of the crowded mice increased by about 80 %, while that of the cortex increased by about 30 %. Simultaneously, the epidermal mitotic rate fell by about 60 %. The effects of the adrenal hormones on epidermal mitosis were next studied. It was found that adrenaline has a powerful antimitotic action both in vivo and in vitro, and that the same is true of the glucocorticoid hormone, 11-dehydro-17-hydroxycorticosterone-21-acetate (cortisone). It is suggested that the antimitotic effects of stress may be due to a high rate of secretion of either, or both, these adrenal hormones, and that these substances act through some interference in carbohydrate metabolism. When energy production is inhibited, it is known that, while no new epidermal mitosis can develop, there is no impediment to the completion of any division already in progress, and this is the precise pattern of inhibition produced by both adrenaline and cortisone. Evidence is reviewed to suggest that the antimitotic action of these hormones may be related to an inhibition of hexokinase. Adrenaline is not known to affect this enzyme, but it is rapidly oxidized to adrenochrome which does. It is shown that adrenochrome has a powerful antimitotic action.