DAILY FLUCTUATIONS OF FUROSEMIDE DIURETIC EFFECT AT RATS

Abstract

THE AIM. Definition of furosemide diuretic activity dependence from time of its introduction to rats and identification of revealed distinctions possible reasons. MATERIALS AND METHODS. In experiments on rats daily fluctuations of furosemide effect was defined and histologically – functional activity of renal tubule cells capacity (by means of cytomorphometry). Diuresis was measured in 6 and 24 hours after administration, containing of Na, K, creatinine and furosemide was detected, nuclearcytoplasmatic relations in epithelial cells of renal tubules and correlation of active and inactive renal cells were counted. RESULTS. Furosemide introduction at 12.00 led to fast increasing of diuretic activity preserving during the day, substantial growth of sodium and potassium rejection, increase of daily creatinine excretion. At furosemide introduction at 24.00 number of quantitative differences was found: more significant diuretic and especially natriuretic effect, increase of potassium and creatinine excretion at night. Cytomorphometry data indirectly confirmed that during the dark period of day functional renal activity of rats is essentially higher then at day-time. CONCLUSION. Diuretic effect of furosemide at rats is subject to circadian fluctuations and is more expressed at night. Daily fluctuations in furosemide effect at rats operation are caused by changes of functional renal activity during the day.