Effect of age on endothelin-1 binding sites in rat cardiac ventricular membranes.
To establish whether the density, affinity, or selectivity of endothelin-1 (ET-1) binding sites in cardiac ventricular membranes varies with age, membranes were harvested from 5- to 7-day-, 20-day-, and 8- to 9-week-old Sprague Dawley rats and labeled with [125I]ET-1. Selectivity was established by using cold ET-1, ET-2, ET-3, big ET-1, and (+)PN200-110 to inhibit specific binding of [125I]ET-1. Over the age span studied, selectivity and affinity of the [125I]ET-1 binding sites was unchanged, but density (Bmax) decreased from 209.7 +/- 18.4 at 5-7 days to 154.0 +/- 8.9 (p less than 0.02) at 20 days, and to 89.7 +/- 5.2 (p less than 0.01) fmol/mg protein at 8-9 weeks. These age-dependent differences in Bmax were not accompanied by a change in membrane yield and occurred at a time when the specific binding of (+)[3H]PN200-110 increased.
Gu
X H
XH
Department of Medicine, University of Melbourne, Austin Hospital, Heidelberg, Australia.
Ou
R C
RC
Casley
D J
DJ
Daly
M J
MJ
Nayler
W G
WG
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002118:Calcium / Q000037:antagonists & inhibitors; D004095:Dihydropyridines / Q000378:metabolism / Q000494:pharmacology; D019332:Endothelin-1; D016232:Endothelins / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D006352:Heart Ventricles / Q000378:metabolism; D017275:Isradipine; D008566:Membranes / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011498:Protein Precursors / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017466:Receptors, Endothelin; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D004095:Dihydropyridines; D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium; D017275:Isradipine