Renal and adrenal adenosine 3',5'-monophosphate production and corticosteroid secretion in response to synthetic chicken parathyroid hormone-(1-34).

The activity of synthetic chicken (c) PTH-(1-34) amide was tested in dispersed chicken and rat kidney and adrenocortical cells. In the adrenal cells the effect of intact cPTH was also evaluated. In chicken kidney cells, the time- and dose-response patterns of cAMP production were similar for cPTH-(1-34) amide and human (h) PTH-(1-34), whereas rat kidney cells were considerably more sensitive to hPTH-(1-34) than to cPTH-(1-34) amide. The agonist effects of both hPTH-(1-34) and cPTH-(1-34) amide in kidney cells were inhibited by the bovine PTH-(3-34) analog. In chicken adrenocortical cells, cPTH-(1-34) amide stimulated cAMP production and steroid secretion. This action of the peptide was inhibited by bovine PTH-(3-34) and hPTH-(1-34), which by themselves showed no agonist effects. The maximal response of steroid secretion to cPTH-(1-34) amide was significantly lower than that to ACTH, but intact cPTH (supplied as a semipurified parathyroid extract) stimulated steriodogenesis to the same extent as ACTH. In rat adrenocortical cells, intact cPTH stimulated both cAMP formation and steriodogenesis, but cPTH-(1-34) amine showed no agonist effect. The action of the intact hormone in the rat adrenal could be inhibited by cPTH-(1-34) amide. The present results demonstrate the interaction of cPTH-(1-34) with kidney and adrenocortical cells of either chicken or rat. The cAMP and steroidogenic responses of the adrenocortical cells to PTH appear to be dependent (completely in the rat and partially in the chicken) on some sequence beyond the 1-34 region.