Characteristics of the kidney functional state after a single dose of thyroxine in white rats

A 50 mcg/100 g b.w. single dose of thyroxine was injected to non-inbred white rat males with body mass 140-180 g in conditions of 5% water and osmotic (3% solution of sodium chloride) load, then renal function was studied. This injection reduced creatinine clearance and phosphate excretion, raised nitrate and protein excretion. The kidney of the hyperthyroid animals retains ability to increase creatinine clearance in response to osmotic load. Thus, the above model demonstrates that in the absence of thyroxine renal toxicity it changes homeostatic renal functions both at the vascular-glomerular and tubular levels.