Hibernation "trigger" alters renal function in the primate.

Macaque monkeys acclimatized to a restraint chair were fitted with indwelling venous and urinary catheters. After basal rates of urine production and creatinine clearance were determined, a 50 mg dose of plasma dialysate albumin fraction obtained from the woodchuck was administered intravenously in a total volume of 2.5 ml. Plasma fractions were collected during the winter interval of hibernation (hibernation "trigger" or HT), or during the summer active (SAWA) period. Although the SAWA fraction exerted no effects on renal function, HT caused a significant reduction in creatinine clearance. In addition, a tendency toward reduced urine flow and creatinine production occurred following the HT infusion. These findings suggest that over and above the hypothermia, aphagia and opioid-like behavioral depression induced by HT, the albumin fraction (HT) present endogenously in the woodchuck during winter torpor, exerts a direct action on the kidney of the primate, possibly on the mechanisms underlying glomerular filtration and the tubular reabsorption process.