Influence of estrogens on electrolyte and water exchanges in the ovariectomized rat

¹ Department of Physiology, College of Physicians and Surgeons, Columbia University, New York City

Daily measurements in rats of food and water intakes, and urine and electrolyte excretion during 7 days feeding and 5 days food deprivation were made on the following groups: normal males, normal and ovariectomized females, ovariectomized receiving 10, 50, and 100 µg diethylstilbestrol (DES) or 5 µg estradiol dipropionate, and ovariectomized pair-fed to the 100 µg DES group. Only 50 and 100 µg of DES resulted in significant reductions in water and food intakes, urinary volume, sodium, potassium, chloride and Na:K ratio. Pair-fed rats had similar decreases except for the Na:K ratio which remained normal. Except for the latter, all effects of high estrogen dosages can be attributed to reduced food intake. Estrogen did not alter glomerular filtration rate or serum electrolyte concentrations. Food deprivation caused a reduction in fluid exchange and electrolyte excretion in all except the ovariectomized animals which had an initial greater fluid turnover. Thus, DES, in high dosages, depressed the Na:K ratio in the ovariectomized rat, an effect which was independent of the electrolyte intake.

Key Words: DES and urinary sodium: potassium ratio • estrogens and water intake • estrogens and food intake • estrogens and electrolyte excretion • diethylstilbestrol • urinary Na:K ratio

Submitted on July 5, 1963