Calcium reveals different mechanisms of guanylate cyclase activation by atrial natriuretic factor and ATP in rat lung membranes.
CaCl2 inhibited ATP-stimulated guanylate cyclase activity, but had little effect on basal and atrial natriuretic factor-stimulated guanylate cyclase activity in rat lung membranes. LaCl3 had similar effects as CaCl2 on basal and stimulated guanylate cyclase activity. LiCl and other monovalent salts inhibited ATP-stimulated guanylate cyclase activity more than basal enzyme activity. However, atrial natriuretic factor somehow stabilized the enzyme against the inhibitory effect of LiCl. These results suggest that ATP and atrial natriuretic factor activate the enzyme through different mechanisms. Since the effect of calcium on guanylate cyclase activity is different from that of monovalent salts and can be mimicked by lanthanum, it may be mediated by a specific calcium binding site or binding protein.
Chang
C H
CH
Department of Medicine, Case Western Reserve University, Cleveland, OH.
Jiang
B
B
Douglas
J G
JG
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000535:Aluminum / Q000494:pharmacology; D000077410:Aluminum Chloride; D017607:Aluminum Compounds; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002122:Calcium Chloride / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D002712:Chlorides / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D007811:Lanthanum / Q000494:pharmacology; D008094:Lithium / Q000494:pharmacology; D018021:Lithium Chloride; D008168:Lung / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D017607:Aluminum Compounds; D002712:Chlorides; C472610:atrial natriuretic peptide, rat; C028521:lanthanum chloride; D000077410:Aluminum Chloride; D007811:Lanthanum; D009320:Atrial Natriuretic Factor; D000255:Adenosine Triphosphate; D008094:Lithium; D000535:Aluminum; D006162:Guanylate Cyclase; D018021:Lithium Chloride; D002122:Calcium Chloride; D002118:Calcium