Acute renal response to large doses of intravenous prednisolone in kidney homograft recipients and in normal subjects.

The immediate renal response to large intravenous doses of prednisolone was studied in 18 kidney homograft recipients and in 6 normal subjects. Clearance rates of inulin (C), creatinine (C), p-aminohippurate (C), and electrolytes were measured over 3 one-hour periods following intravenous infusion of prednisolone (1 Gm.) and compared with corresponding clearance rates after a placebo infusion. C, C, and C rates and ratios exhibited a substantial decrease during all collection periods following the infusion of prednisolone, both in the normal subjects and in the patients. Fractional excretion of potassium increased in a progressive fashion reaching peak values after 3 hours. Biphasic variations were observed in the fractional excretion of sodium ; an increase during the first hour was followed by a decrease during the third hour. The changes in the fractional excretions of ultrafiltrable calcium , ultrafiltrable magnesium , and phosphorus were minimal. Normal subjects exhibited significant decreases in and following the infusion of prednisolone; there was no significant change in the patients. increased significantly both in the normal subjects and in the patients. These results indicate that acute suppression of kidney function is a general renal response to large doses of glucocorticoids. The marked decrease in the creatinine clearance ratio observed after the administration of prednisolone is consistent with a depressed tubular secretion of creatinine and emphasizes the inadequacy of C as an indication of glomerular filtration rate (GFR) under conditions in which large doses of glucocorticoids are employed.