Binding of synthetic beta-human atrial natriuretic peptide to cultured rat vascular smooth muscle cells.
We have studied the effects of synthetic beta-human atrial natriuretic peptide (beta-hANP), an antiparallel dimer of alpha-hANP, on receptor binding and cGMP generation in cultured rat vascular smooth muscle cells and compared the effects with those of alpha-hANP. Characteristics of temperature-dependent binding and degradation of 125I-beta-hANP were similar to those of 125I-alpha-hANP. Scatchard analysis indicated a single class of binding sites for beta-hANP with a maximal binding capacity one-half that of alpha-hANP. Parallel and antiparallel dimers were equipotent in inhibiting the binding and stimulating intracellular cGMP formation, of which the maximal effect was about one-half that of alpha-hANP. Reverse-phase high performance liquid chromatography revealed that most of beta-hANP added to cells was converted to a small molecular mass component corresponding to alpha-hANP after incubation. These data suggest that the less potent effect of beta-hANP in receptor binding and cGMP generation may be partly accounted for by the possible conversion of beta-hANP to alpha-hANP at the site of target cells.
D000818:Animals; D001011:Aorta / Q000378:metabolism; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000378:metabolism*
D046911:Macromolecular Substances; D011956:Receptors, Cell Surface; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP