Alpha 2-adrenergic receptors in brown adipose tissue of infant rats--II. Studies on function and regulation.
1. Clonidine inhibited the forskolin- and MIX-induced rate of lipolysis in brown fat adipocytes isolated from interscapular brown fat of 7-day-old rats. Its effect could be prevented by the alpha 2-antagonist yohimbine. 2. Pertussis toxin prevented the above effect of clonidine, thus indicating that alpha 2-adrenoceptors are linked with adenylate cyclase via the Ni regulatory subunit. 3. Chemical sympathectomy of 5-day-old rats by 6-hydroxydopamine increased the number of low-affinity alpha 2 sites in brown fat. 4. Chronic administration of yohimbine to 2-3-week-old rats also increased the density of alpha 2-adrenoceptors in brown fat. 5. It is suggested that brown fat of infant rats possesses functional alpha 2-adrenoceptors.
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D037361:Adenylate Cyclase Toxin; D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D006892:Hydroxydopamines; D007700:Kinetics; D008066:Lipolysis / Q000187:drug effects; D016627:Oxidopamine; D037342:Pertussis Toxin; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D013563:Sympathectomy, Chemical; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
D037361:Adenylate Cyclase Toxin; D006892:Hydroxydopamines; D011942:Receptors, Adrenergic, alpha; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D015016:Yohimbine; D016627:Oxidopamine; D037342:Pertussis Toxin; D003000:Clonidine; D015056:1-Methyl-3-isobutylxanthine