Circadian rhythms in the urinary excretion of phosphate and cyclic 3',5'-adenosine monophosphate in kidney graft recipients.

Circadian rhythms of urinary phosphate excretion in 13 supine and 8 ambulatory kidney graft recipients in the late post-transplant period were studied. A comparison of serum phosphate level and urinary phosphate excretion revealed two groups of patients: a) with normal serum phosphate level and a high urinary phosphate excretion, and b) patients with subnormal serum phosphate and a moderate phosphate excretion. Compared to control group of 9 healthy volunteers much greater variations in phosphate and cyclic 3',5'-AMP excretion in grafted patients were recorded. An inversed phosphate excretion rhythm was observed in 5 out 13 supine patients.