Acute effect of prednisolone on renal handling of sodium.

The effect of prednisolone on renal handling of sodium (Na) was studied in rats under three experimental conditions: 1) hydropenia, 2) water diuresis, and 3) distal tubular blockade (DTB). Prednisolone, 0.25 mg/100 g per hr, was infused directly into left renal artery and urine was collected separately from each kidney. Predominantly unilateral increases in urine flow (V) and Na excretion were noticed in all experiments during prednisolone infusion. In the hydropenic rats the maximal increments on the infused side were, for V (mean ± SD), from 9.3 ± 1.5 to 21.4 ± 0.8 μl/min (P < 0.001); for C(Na)/C(In), from 0.28 ± 0.11 to 2.97 ± 0.71 % (P < 0.005); and for [Formula: see text] , from 2.93 ± 2.26 to 5.32 ± 1.92% (P < 0.05). In the rats with water diuresis, the maximal increases were, for V/C(In), from 5.87 ± 1.97 to 10.1 ± 6.0% (P < 0.005); for C(H(2)O)/C(In), from 4.09 ± 0.68 to 6.00 ± 0.44% (P < 0.0005); and for C(Na)/C(In), from 0.22 ± 0.07 to 0.70 ± 0.38% (P < 0.01). In DTB-rats the maximal increases were for V from 48.6 ± 9.0 to 72.7 ± 14.1 μl/min (P < 0.0005) and for C(Na)/C(In) from 9.42 ± 2.97 to 20.23 ± 7.34% (P < 0.005). In the contralateral kidney these changes were less pronounced. These observations suggest that prednisolone depresses directly Na reabsorption. The association of natriuresis with augmented [Formula: see text] and C(H(2)O)/C(In) during hydropenia and water diuresis, respectively, and the increases in V and C(Na)/C(In) during DTB, all are consistent with inhibition of Na reabsorption in the proximal tubule

Acute Alteration of Plasma Renin Activity by Large Doses of Intravenous Prednisolone

Large doses of intravenous glucocorticoids have been used in an attempt to reverse homograft rejection. The intravenous administration of 1 g prednisolone over 1 hr resulted in a significant acute reduction of plasma renin activity in 5 normal subjects tested and in 11 out of 15 patients bearing renal homografts. No definite explanation for failure to respond nor the mechanism of this prednisolone effect is readily at hand. An acute decrease in renin activity could be salutary for the chronically or acutely rejecting patient in that it could reduce vasopressor and salt-retaining effects. However, several of the non-responders had an increase in renin activity which could have been detrimental. © 1972, SAGE Publications. All rights reserved

Serum parathyroid hormone levels and renal handling of phosphorus in patients with chronic renal disease

In eight patients with advanced renal insufficiency (inulin clearance 1.4-9.1 ml/min), concentrations of serum calcium (S[Ca]) and phosphorus (S[P]) were maintained normal (S[Ca] > 9.0 mg/100 ml, (S[P] < 3.5 mg/100 ml) for at least 20 consecutive days with phosphate binding antacids and oral calcium carbonate. The initial serum levels of immunoreactive parathyroid hormone (S-PTH) were elevated in three (426-9230 pg/ml), normal in four (one after subtotal parathyroidectomy), and not available in one. The initial fractional excretion of filtered phosphorus was high in all and ranged from 0.45-1.05. Following sustained normo-calcemia and normo-phosphatemia, S-PTH was reduced below control levels in all patients; being normal in six and elevated in two. decreased below control levels in all patients; it remained high in six (of which five had normal S-PTH) and was normal in two (of which one had elevated S-PTH). The observed relationship between S-PTH and could either reflect the inability of the radioimmunoassay for PTH employed to measure a circulating molecular species of PTH which was present in which case the actual levels of S-PTH were higher than those measured, and/or it could be indicative of the presence of additional important factor(s) (other than S-PTH) which inhibit tubular reabsorption of phosphorus in advanced chronic renal failure. © 1972 by The Endocrine Society

Hypernatremia: Complication of Renal Homotransplantation

Hypernatremia was observed in five recipients of renal homografts during the first postoperative week. The peak serum levels of sodium varied between 152 and 158 mEq/liter. The postoperative diuresis was associated with sodium concentration in the urine, consistently lower than that in the extracellular water; moderate urinary hypertonicity, with urea being the main urinary solute; and urea excretion exceeding 60% of its filtered load in most instances. The inability of elaborate urine with sodium concentration equal or higher than that in the serum, possibly related to osmotic diuresis and/or altered renal hemodynamics, appears to be the primary cause responsible for the development of hypernatremia in these patients. © 1971, American Medical Association. All rights reserved

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 (CIN), creatinine (CCR), p-aminohippurate (CPAH), 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. CIN, CCR, and CPAH rates and ( CCR CIN) 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 ( CK CIN) increased in a progressive fashion reaching peak values after 3 hours. Biphasic variations were observed in the fractional excretion of sodium ( CNA CIN); an increase during the first hour was followed by a decrease during the third hour. The changes in the fractional excretions of ultrafiltrable calcium ( CCa CIN), ultrafiltrable magnesium ( CMg CIN), and phosphorus ( CP CIN) were minimal. Normal subjects exhibited significant decreases in ( CCa CIN) and ( CMg CIN) following the infusion of prednisolone; there was no significant change in the patients. ( CP CIN) 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 ( CCR CIN) observed after the administration of prednisolone is consistent with a depressed tubular secretion of creatinine and emphasizes the inadequacy of cCR as an indication of glomerular filtration rate (GFR) under conditions in which large doses of glucocorticoids are employed. © 1971