Effect of estrogen-progestogen administration on tissue cation concentrations in the rat

Five studies are reported which were designed to define the effects of an estrogen and a progestogen, alone and in combination, on tissue concentrations (heart, kidney, and liver) of two trace metals (zinc, copper) and four bulk cations (sodium, potassium, calcium, magnesium). Male rats received Premarin (0.08 mg) and/or progesterone (2 mg) in saline intramuscularly 5 days a week for 12 weeks. A significant increase in kidney copper concentrations was the most striking finding in treated, compared to control, animals. A small but significant increase in kidney zinc concentrations also was observed. The changes in cation concentrations in the liver were less striking and consistent, and no changes were observed in cation concentrations of heart muscle. The increase in renal copper was greater with estrogen than with progestogen alone but the two in combination produced an additive effect. Dose-response and time-response changes were documented. Two weeks after discontinuing treatment, renal copper and zinc concentrations returned to control levels.