Adrenocorticotropic stimulation and insulin inhibition of adipocyte phospholipid methylation.
Treatment of isolated rat adipocytes with adrenocorticotropin (ACTH) caused a 1.5-fold increase in phospholipid methyltransferase activity within 5 min. This effect of ACTH was concentration-dependent with maximal activation at 2 milliunits/ml ACTH, and was reproduced by dibutyryl cyclic AMP. ACTH (2 milliunits/ml) caused an increase in the Vmax value of phospholipid methyltransferase without changing the Km for S-adenosyl-L-methionine. Insulin caused a concentration-dependent inhibition of both control and ACTH-stimulated phospholipid methyltransferase. Half-maximal inhibition by insulin was demonstrated with 5 microunits/ml insulin in control cells and with 25 microunits/ml insulin in ACTH-stimulated cells. The rapid and sensitive activation of adipocyte phospholipid methyltransferase by ACTH and inhibition by insulin are consistent with a role for this pathway in the hormonal response of the adipocyte.
Kelly
K L
KL
Wong
E H
EH
Jarett
L
L
D000273:Adipose Tissue / Q000187:drug effects*; D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002855:Chromatography, Thin Layer; D004305:Dose-Response Relationship, Drug; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism; D050941:Phosphatidyl-N-Methylethanolamine N-Methyltransferase; D010713:Phosphatidylcholines / Q000378:metabolism; D050918:Phosphatidylethanolamine N-Methyltransferase; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010743:Phospholipids; C032000:phosphatidyl-N-monomethylaminoethanol; C026508:phosphatidyldimethylethanolamine; D003994:Bucladesine; D000324:Adrenocorticotropic Hormone; D008780:Methyltransferases; D050918:Phosphatidylethanolamine N-Methyltransferase; D050941:Phosphatidyl-N-Methylethanolamine N-Methyltransferase