A time course study of the effect of repetitive doses of estradiol-17 beta on serum glucose and lipids, liver glycogen and some carbohydrate metabolizing enzymes in liver of male flounder (Platichtys flesus L.).

1. Repeated treatment of male flounder with 5 and 100 microgram doses of estradiol-17 beta increases the level of phospholipid, triglyceride, free fatty acids and total lipid in serum as a function of time and dose, during a period of 17 days. 2. The glucose level in serum is increased and decreased respectively by doses of 5 and 100 micrograms. 3. Five and 100 microgram doses decrease the level of glycogen in liver. 4. Five microgram doses do not affect the activity of the measured enzymes considerably, with the exception of phosphorylase a. 5. One hundred microgram doses increase the activity of glucose-6-phosphate dehydrogenase after 11 days. 6. One hundred microgram doses increase the activity of pyruvate kinase continuously during the experimental period and decrease phosphorylase a and glucose-6-phosphatase activity.