Developmental changes in ANP-stimulated guanylyl cyclase activity enhanced by ATP in rat lung membrane fractions.
1. ANP (atrial natriuretic peptides)- or ANP/ATP-stimulated guanylyl cyclase activities were compared in adult (2 month old) and neonatal (5-7 day old) rat lung membrane fractions. 2. The enzyme activities of both membranes depended on the incubation time and ATP concentration: although the activities of both membranes were similar after a short incubation time (4 min), those in adult membranes were lower than those of neonatal membranes after longer incubation times (10 and 30 min) or at lower concentrations of ATP. 3. ANP/ATP gamma S-stimulated guanylyl cyclase activities, which were much higher than ANP/ATP-stimulated activities, were similar in both membranes. 4. ATPase activity of adult membranes was higher than that of neonatal membranes, suggesting that hydrolysis of ATP leads to a decrease of ANP/ATP-guanylyl cyclase activity in adult membranes. Triton X-100 enhanced and diminished ANP/ATP-stimulated guanylyl cyclase activities of adult and neonatal membranes, respectively, and thereby abolished the adult/neonatal difference in the membrane response to ATP. 5. ANP-stimulated activities of both membranes were much more activated by pre-incubation with ATP gamma S than those induced by simultaneous addition of ATP gamma S. The former activities were decreased to levels of the latter by Triton X-100. The latter activities were not affected by Triton X-100. 6. The present results suggested that conformation of lung plasma membranes is related to activation of the ANP receptor/guanylyl cyclase system.
Department of Pharmacology, Faculty of Pharmaceutical Sciences Hokkaido University, Sapporo, Japan.
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Charoonroje
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Tokumitsu
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Nomura
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D006162:Guanylate Cyclase / Q000378:metabolism*; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects; D008566:Membranes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D017830:Octoxynol / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D011506:Proteins; C022571:adenosine 5'-O-(3-thiotriphosphate); D009320:Atrial Natriuretic Factor; D000255:Adenosine Triphosphate; D017830:Octoxynol; D000251:Adenosine Triphosphatases; D006162:Guanylate Cyclase