These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Role of beta1- and beta3-adrenoceptors in the regulation of lipolysis and thermogenesis in rat brown adipocytes.
    Author: Atgié C, D'Allaire F, Bukowiecki LJ.
    Journal: Am J Physiol; 1997 Oct; 273(4):C1136-42. PubMed ID: 9357756.
    Abstract:
    To evaluate the physiological functions of beta1-, beta2-, and beta3-adrenoceptors (ARs) in brown adipose tissue, the lipolytic and respiratory effects of various adrenergic agonists and antagonists were studied in rat brown adipocytes. The beta-agonists stimulated both lipolysis and respiration (8-10 times above basal levels), with the following order of potency (concentration eliciting 50% of maximum response): CL-316243 (beta3) > BRL-37344 (beta3) > isoproterenol (mainly beta1/beta2) > norepinephrine (NE; mainly beta1/beta2) > epinephrine (mainly beta1/beta2) >> dobutamine (beta1) >> procaterol (beta2). Schild plot coefficients of competitive inhibition experiments using ICI-89406 (beta1 antagonist) revealed that more than one type of receptor mediates NE action. It is concluded from our results that 1) NE, at low plasma levels (1-25 nM), stimulates lipolysis and respiration mainly through beta1-ARs, 2) NE, at higher levels, stimulates lipolysis and respiration via both beta1- and beta3-ARs, 3) beta2-ARs play only a minor role, and 4) beta3-ARs may represent the physiological receptors for the high NE concentrations in the synaptic cleft, where the high-affinity beta1-ARs are presumably desensitized. It is also suggested that lipolysis represents the flux-generating step regulating mitochondrial respiration.
    [Abstract] [Full Text] [Related] [New Search]