Regulation of white adipocyte guanine nucleotide binding proteins Gs alpha and Gi alpha 1-2 by testosterone in vivo: influence of regional fat distribution.
The influence of the androgenic status on the steady-state amounts of Gi alpha 1-2 and Gs alpha subunits was compared in hamster fat cell membranes from the femoral subcutaneous (FSC) and epididymal (EP) adipose tissues, using immunoblotting experiments. In sham-operated hamsters, Gi alpha 1-2 and Gs alpha steady-state amounts found in FSC fat cells were 38% and 40% reduced, respectively, as compared to EP adipocytes. In EP fat cells, castration induced a down-regulation of both Gi alpha 1-2 (-39%) and Gs alpha (-33%), whereas testosterone replacement restored Gs alpha, but not Gi alpha 1-2 levels, to control values. In contrast, these G protein alpha-subunits were insensitive to the androgenic status in FSC fat cells. These data provide the first evidence that the androgenic status can modulate the expression of both the Gi alpha 1-2 and Gs alpha subunits of the fat cell adenylate cyclase regulatory Gi and Gs proteins and that this modulation depends on the anatomical origin of these cells.
Dieudonne
M N
MN
Service de Biochimie, Faculté de Médecine Paris-Ouest, Centre Hospitalier de Poissy, France.
Pecquery
R
R
Dausse
J P
JP
Giudicelli
Y
Y
D000262:Adenylyl Cyclases / Q000378:metabolism; D000273:Adipose Tissue / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002369:Castration; D006224:Cricetinae; D015536:Down-Regulation; D004822:Epididymis; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008297:Male; D012867:Skin; D013739:Testosterone / Q000494:pharmacology*
D013739:Testosterone; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases