A study of mitosis in mouse ear epidermis in vitro: V. Effects of hormones

Abstract

1. 1. The present study examines the question of whether hormones stimulate or inhibit mitotic activity because of their influence on glucose utilization and energy production for mitosis in mouse ear epidermis cultured in vitro. 2. 2. Estrone, estradiol, testosterone, progesterone and ACTH generally had no effect on epidermal mitotic activity; adrenalin, adrenochrome, insulin, growth hormone and DOCA inhibited mitosis to various degrees and with various consistencies; and glucagon increased mitotic activity under certain conditions. 3. 3. Testing these hormones in the presence of three different concentrations of glucose indicated that the mitotic action of a hormone in vitro is not a result of merely increasing or decreasing the available intracellular glucose supply. 4. 4. The belief that insulin and the growth hormone mediate their mitotic, effects specifically through the glucokinase reaction was shown to be invalid. 5. 5. Trace quantities of metals (possible hormone contaminants) by themselves are capable of increasing or inhibiting epidermal mitotic activity. 6. 6. Further evidence is presented to question the actual function of glucose as an energy metabolite for epidermal mitosis in vitro (non-utilizable sugars also support mitotic activity). 7. 7. All of our results support the contention that hormonal influences on epidermal mitotic activity are neither related to the known biological effects of a hormone or to any specific energy requirements for mitosis.