Beta-3 adrenoceptor (beta-3AR) expression in leptin treated OB/OB mice.
Leptin-deficient Ob/Ob mice are hypometabolic and have reduced fat cell expression of beta-3 adrenoceptors (ARs). To determine whether leptin repletion restores beta-3 AR number, C57BL/6J Ob/Ob mice were given exogenous leptin (5 mg/kg I.P. daily) for 21 days. Leptin administration reduced body weight from 43.1+/-3.7 to 34.1+/-3.7 g in Ob/Ob animals but had no effect on weight in wildtype animals. Body weight increased by 12% in Ob/Ob mice receiving saline. Beta-3 AR mRNA concentrations were markedly reduced in Ob/Ob animals at baseline. Leptin increased beta-3 AR mRNA to control levels in Ob/Ob mice, but had no effect in wildtype animals. Adipocyte leptin mRNA was increased by 400% in Ob/Ob mice and did not suppress with exogenous leptin administration, suggesting no direct feedback regulation of leptin synthesis. We speculate that restoration of beta-3 AR expression by repleting leptin may be important in correcting hypometabolism in Ob/Ob animals.
Breslow
M J
MJ
The Johns Hopkins Medical Institutions, Department of Anesthesiology/Critical Care Medicine, Baltimore, Maryland 21287-8711, USA. mbreslow@welchlink.welch.jhu.edu
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Berkowitz
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D000818:Animals; D020738:Leptin; D051379:Mice; D008817:Mice, Mutant Strains; D009765:Obesity / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D054411:Receptors, Leptin
D020738:Leptin; D011506:Proteins; D012333:RNA, Messenger; D011943:Receptors, Adrenergic, beta; D054411:Receptors, Leptin; C515447:leptin receptor, mouse