Effect of meglumine iothalamate on renal hemodynamics and function in the diabetic rat

Diabetic rats were given an intravenous (external jugular vein) injection of 3 mg/kg of 60% meglumine iothalamate to test for this contrast agent's functional effects on the kidney. Rats were made diabetic by the intravenous injection of 60 mg/kg streptozotocin six months prior to the experiment and received no treatment during the interim. Glomerular filtration rate, renal blood flow, blood pressure, and sodium reabsorption were measured immediately before and at timed intervals after the administration of the contrast agent. In the diabetic rats, meglumine iothalamate caused a small and brief increase in renal blood flow followed by a sustained decrease; in the control animals an initial rapid rise was followed by a sustained elevation. Glomerular filtration rate also decreased slightly after contrast agent injection and remained depressed below baseline in the diabetic rats, whereas in the control animals it rose slightly above baseline and returned to control values by the end of the experiment. Sodium reabsorption was initially much higher than that of the controls, and it remained much higher throughout the experiment but decreased slightly just after injection of the contrast agent. Volume expansion of the diabetic animals decreased fractional sodium reabsorption to levels similar to those of the control rats but did not normalize the response of renal blood flow, glomerular filtration rate, or sodium reabsorption. Dehydration of control animals increased initial sodium reabsorption to levels similar to those of the diabetic animals but did not normalize the response to the contrast agent of the glomerular filtration rate, renal blood flow, or sodium reabsorption.(ABSTRACT TRUNCATED AT 250 WORDS)