Serum and urine phosphate during short-term beta-adrenergic blockade in healthy men

Treatment of 6 healthy adult men with a beta-blocker, timolol, resulted in a rise in serum phosphate which was maintained for the 5 days of therapy. This rise was accompanied by a transient fall in urine phosphate and a rise in the tubular maximum for phosphate reabsorption per unit glomerular filtration rate (TmPO4/GFR). No change in circulating parathyroid hormone or growth hormone could be demonstrated.