Melanotropin potentiating factor inhibits lipolytic activity of beta-lipotropin but not of melanocyte stimulating hormones.
Melanotropin potentiating factor (MPF) potentiates the melanotropic activity of melanocyte stimulating hormones. Although the message sequence for the melanotropic and lipolytic activity are identical for beta-lipotropin, alpha- and beta-MSH, MPF was not able to affect the lipolytic response to alpha- and beta-MSH in rabbit adipocytes. However, MPF at concentrations of 10-5 and 10-6 mol/l inhibited the lipolytic activity of beta-lipotropin. This suggests that the inhibition of the lipolytic response to beta-lipotropin is not connected with the common lipolytic message sequence (beta-LPH 47-53). Since beta-lipotropin has a second lipolytic sequence in its C-terminal part this second lipolytic core of beta-lipotropin might interact with MPF which has no intrinsic lipolytic activity.
D000273:Adipose Tissue / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D004151:Dipeptides / Q000494:pharmacology*; D004347:Drug Interactions; D004723:Endorphins; D005990:Glycerol / Q000378:metabolism; D008066:Lipolysis / Q000187:drug effects*; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D010446:Peptide Fragments; D011817:Rabbits; D008083:beta-Lipotropin / Q000037:antagonists & inhibitors*
D004151:Dipeptides; D004723:Endorphins; D010446:Peptide Fragments; C050079:lysyl-lysyl-glycyl-glutamic acid; D009074:Melanocyte-Stimulating Hormones; D008083:beta-Lipotropin; D005990:Glycerol