Effect of Russell's viper venom on kidney functions of hyperthyroid and hypothyroid rats

Abstract

The present investigation aims to study whether change in renal function of either hyperthyroid or hypothyroid rats is affected by Russell's viper venom. Decrease In hematocrit value was observed in all three groups of rats given the venom, Heart rate and mean arterial blood pressure decreased in hyperthyroid rats while changes of these two parameters were not found in normal and hypothyroid rats. Renal blood flow and glomerular filtration rate decreased while renal vascular resistance increased in normal and hypothyroid rats. Urinary excretion of potassium, chloride and calcium decreased while no change in urinary excretion of sodium was observed in these two groups. Plasma concentration of the electrolytes did not change but the increase of plasma creatinine and urea were observed. The study in hyperthyroid rats found that urine flow rate, free water clearance, plasma concentration of chloride and calcium increased while the other parameters did not change. These results Indicate that L-thyroxine alleviated the effect of Russell's viper venom. The protective effect of L-thyroxine against the venom nephrotoxicity may be due to the beneficial effect of hypercalcemia which inhibits renin secretion. Renin-angiotensin system has been suggested to induce a renal vasoconstriction after envenomation. The renal vasoconstriction may play some roles in the initial pathogenesis of acute renal failure.