Hormones, Carbohydrate Metabolism, and Mitosis

Hormones, Carbohydrate Metabolism, and Mitosis 1. Hormones and Enzymes 

The probability that animal and plant hormones exert their effects through their control of one or more critical enzyme systems is now gen- 

Average numbers of mitoses arrested by colchicine in 4 hr. in unit lengths (1 cm.) of sections 7 m thick of mouse ear epidermis incubated at 38°C. in 4 ml. saline medium with an oxygen gas phase. Each figure is the average of 5 observations. 

Substrate Alone +0.5 Mg. insulin +5 Mg. insulin +50 Mg. inaiilin +250 Mg. insulin 

Clearly insulin is capable of stimulating the epidermal mitotic rate, and that this is due to its action on the enzyme glucokinase is shown by coincident experiments in which fructose was used as substrate. It is evident that fructose is a more efficient substrate for epidermal mitotic activity than is glucose, and that insulin exerts no stimulus to the efficiency of the epidermal fructokinase system. 

---