Externalization and internalization of (Na+ + K+)-ATPase in rat heart during different phases of sepsis.
Changes in the distribution of (Na+ + K+)-ATPase in two subcellular fractions, the sarcolemma and the light vesicle, of rat heart during sepsis were studied. Sepsis was induced by cecal ligation and puncture (CLP). The alpha-subunit of (Na+ + K+)-ATPase was photoaffinity labeled with [alpha-32P]8-N3ATP. The results show that septic rat heart exhibits hyperdynamic (hypermetabolic) phase during early (9 hr post-CLP), followed by hypodynamic (hypometabolic) phase during late (18 hr post-CLP) sepsis. Marker enzyme and beta-adrenergic receptor assays depict that the light vesicle fraction is the intracellular site of surface receptor. The incorporation of the photolabel into the alpha-subunit (M(r) = 98,000) of the (Na+ + K+)-ATPase in sarcolemmal fraction was increased by 60% (P < 0.01) during early sepsis, but was decreased by 63% (P < 0.01) during late sepsis. In contrast, the binding of 98,000-M(r) peptide in light vesicles was decreased by 40% (P < 0.01) in early sepsis, but was increased by 102% (P < 0.01) during late sepsis. The ouabain-sensitive (Na+ + K+)-ATPase activity was increased by 31% (P < 0.05) during the early sepsis, but was decreased by 32% (P < 0.01) during late sepsis in the sarcolemmal fraction; while in the light vesicle fraction, the (Na+ + K+)-ATPase activity was decreased by 21% (P < 0.01) during early sepsis, but was increased by 47% (P < 0.01) during the late phase of sepsis. The yield of membrane proteins for each specific fraction remained unchanged for control, early sepsis, and late sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)
Tang
C
C
Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, MO 63104.
Hsu
H K
HK
Chen
X Y
XY
Liu
M S
MS
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D000345:Affinity Labels; D000818:Animals; D001386:Azides / Q000378:metabolism; D001667:Binding, Competitive; D004082:Dihydroalprenolol / Q000378:metabolism; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D007545:Isoproterenol / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000201:enzymology* / Q000648:ultrastructure; D010042:Ouabain / Q000494:pharmacology; D010777:Photochemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism; D012508:Sarcolemma / Q000201:enzymology; D018805:Sepsis / Q000201:enzymology*
D000345:Affinity Labels; D001386:Azides; D011943:Receptors, Adrenergic, beta; D006165:Guanylyl Imidodiphosphate; C017040:8-azidoadenosine 5'-triphosphate; D010042:Ouabain; D004082:Dihydroalprenolol; D000255:Adenosine Triphosphate; D007545:Isoproterenol