EFFECTS OF 9-ALPHA-FLUOROHYDROCORTISONE ON BLOOD PRESSURE, PLASMA VOLUME, AND SODIUM, POTASSIUM AND WATER BALANCE IN RATS

Abstract

ABSTRACT In normal rats on a standard sodium diet, the administration of 9-alpha-fluorohydrocortisone (9aFF) induced a rapid increase of blood pressure in parallel to an increase of plasma volume. Water and potassium balances became negative. Urinary sodium excretion remained unchanged or increased after high doses, whereas urinary sodium concentration and faecal sodium excretion were reduced. The diurnal rhythm of water and sodium excretion changed: during the night-period, renal water and sodium excretion were diminished, whereas during the day-period both were enhanced. Thus, some effects of 9aFF on electrolyte and water balance are similar to those of DOC, while other effects are similar to those of cortisone. It is postulated that a shift of fluid from intracellular to extracellular compartments, which increases plasma volume, is of critical importance for the 9aFF-induced blood pressure elevation in rats.