Effect of acute heat stress on some renal functions in the sickle cell patient.

1. The effect of acute temperature change on some renal functions was studied in 19 young sickle cell patients and 10 normal young adults (AA). 2. Glomerular filtration rate, Renal plasma flow and urine flow rate were highest in the SS followed by the SC and least in the AA at 20 degrees C. At 40 degrees C there was reduction in all the paramenters; the least reduction occurred in the normal controls. At 20 degrees C solute excretion was higher in the patients but at 40 degrees, excretion decreased to value close to that of controls in the SC but in the SS it remained high. 3. At 40 degrees, renal function in the patients approached that in normal controls, particularly in the SC. 4. It is suggested that functional changes occur not only in Henles loops but also in other postglomerular tubules and that the functional defect is unmasked during osmotic plus water diuresis and exposure to cool temperature.