Endogenous biologically active human parathyroid hormone: measurement by a guanyl nucleotide-amplified renal adenylate cyclase assay.

Abstract

The purpose of the present study was to establish and validate a routine procedure for the measurement of endogenous biologically active human parathyroid hormome (PTH). To accomplish this, we measured the activation of canine renal cortical plasma membrane adenylate cyclase activity produced by PTH standards or test sera in the presence of the hydrolysis-resistant GTP analog, 5′-guanylimidodiphosphate (100 [M). In this system, as little as 3 pg (=0 3 fmol) human PTH-(1–U≃84)′ assay tube produced significant adenylate cyclase activation. Glucagon, human calcitonin, ACTH-(l–), arginine vasopressin, epinephrine, and prostaglandin E1 had little or no activity. A competitive PTH antagonist, [8Nle, 18Nle, 34Tyr]bovine PTH(3–34) amide, completely inhibited enzyme activation produced by exogenous PTH, parathyroid venous effluent serum, or peripheral chronic renal failure serum. Thus, the activity in serum was due specifically to biologically active PTH.The concentrations of biologically active PTH and immunoreac...