Kinetic characteristics of hamster (mesocricetus auratus) brown fat (Na+/K+)-ATPase: Effects of catecholamines

D. R. Hettinger, Barbara A Horwitz

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

1. The (Na+/K+-ATPase activity of brown fat membranes is increased by norepinephrine, the physiological mediator of thermogenesis in this tissue. 2. This increased ATPase activity was inhibited approximately 50% by either propranolol (a β-adrenergic blocker) or phentolamine (an α-blocker). 3. The α-agonist, phenylephrine and the β-agonist, isoproterenol, also stimulated the ATPase activity. 4. That these latter effects were receptor-specific is supported by the finding that: (a) l(-)isoproterenol stimulation was inhibited by propranolol but not by phentolamine; (b) d(+)isoproterenol had no stimulatory effect on the ATPase activity; and (c) the l(-)phenylephrine-induced increase was inhibited by phentolamine but not by propranolol. 5. (-)norepinephrine, l(-)isoproterenol and l(-)phenylephrine all decreased the apparent Km for K+ of the (Na+/K+-ATPase but did not alter the apparent Kmfor ATP or the Vmax of the reaction.

Original languageEnglish (US)
Pages (from-to)355-360
Number of pages6
JournalComparative Biochemistry and Physiology. Part C, Comparative
Volume74
Issue number2
DOIs
StatePublished - 1983

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ASJC Scopus subject areas

  • Immunology
  • Pharmacology

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