Influence of cations on kinetics of angiotensin II binding to adrenal, renal, and smooth muscle receptors.
A number of biological responses to angiotensin II have been demonstrated to be modulated acutely by cations, but the exact mechanism has not been elucidated. We have utilized a radioreceptor assay for angiotensin II to determine whether this acute regulatory mechanism could be related to a change in either number or affinity of angiotensin II binding to receptors. Three target tissues were used (adrenal glomerulosa, glomeruli, and uterine smooth muscle). Both mono- and divalent cations influence the kinetics of angiotensin II binding in a similar manner in all tissues. Divalent cations increase the number of receptor sites to a greater extent than did monovalent cations, while monovalent cations changed binding affinity to a greater extent than did divalent cations. These studies demonstrate that both the number and affinity to a greater extent than did monovalent cations, while monovalent cations changed binding affinity to a greater extent than did divalent cations. These studies demonstrate that both the number and affinity of angiotensin receptors can be rapidly modulated by a variety of cations.
D000311:Adrenal Glands / Q000378:metabolism*; D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology*; D002414:Cations, Monovalent / Q000494:pharmacology; D005260:Female; D007678:Kidney Glomerulus / Q000378:metabolism*; D007700:Kinetics; D009130:Muscle, Smooth / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*
D002413:Cations, Divalent; D002414:Cations, Monovalent; D011945:Receptors, Angiotensin; D011956:Receptors, Cell Surface; D000804:Angiotensin II