Alpha 1- and beta-adrenergic receptors in brown adipose tissue of lean (Fa/?) and obese (fa/fa) Zucker rats. Effects of cold-acclimation, sucrose feeding and adrenalectomy.
1. The populations of alpha 1- and beta-adrenergic receptors in brown adipose tissue (BAT) of genetically obese Zucker rats (fa/fa) were studied with [3H]prazosin and [3H]CGP-12177 respectively. 2. The density of alpha 1-adrenergic receptors in BAT was significantly lower in obese than in lean Zucker rats, both at 2-4 months of age and at 6 weeks of age. The density of beta-adrenergic receptors was identical in BAT of lean and obese 6-week-old Zucker rats. 3. Cold-acclimation increased the alpha 1-receptor density significantly in BAT of both lean and obese Zucker rats, and the number of beta-receptors was also somewhat increased. 4. Sucrose feeding did not affect the density of alpha 1-receptors in BAT of lean or obese Zucker rats, but it increased beta-receptor density. 5. Adrenalectomy restored the density of alpha 1-adrenergic receptors in BAT of obese Zucker rats to the value observed in lean rats. 6. It is concluded that there is a direct correlation between alpha 1-receptor density and tissue recruitment, and that alpha 1-receptor density is thus positively correlated with sympathetic activity. beta-Receptor density is apparently better correlated with feeding conditions.
D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism*; D000315:Adrenalectomy; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D003080:Cold Temperature; D005260:Female; D008297:Male; D009765:Obesity / Q000378:metabolism*; D011224:Prazosin / Q000378:metabolism; D011412:Propanolamines / Q000494:pharmacology; D051381:Rats; D011924:Rats, Zucker; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013395:Sucrose / Q000494:pharmacology
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D013395:Sucrose; C033394:CGP 12177; D011224:Prazosin