Influence of adrenalectomy on chronopharmacological phenomenon of furosemide in rats.

The role of adrenal corticoids in the time-dependent changes in the effects of furosemide was examined. Furosemide (30 mg/kg) was given orally to adrenalectomized or sham-operated rats at 12 a.m. or 12 p.m. Urine volume and urinary excretion of sodium and furosemide for 8 hr were significantly greater at 12 a.m. than at 12 p.m. in the sham-operated rats. However, such time-dependent changes in these parameters disappeared in the adrenalectomized animals. These findings indicate that adrenal corticoids are directly or indirectly involved in this event.