Interaction of thymic peptide thymosin alpha 1 with vasoactive intestinal peptide (VIP) receptors.
Thymic peptide thymosin alpha 1 (10(-9) to 3 X 10(-7) M) is shown to inhibit the specific binding of [125I]VIP to rat blood mononuclear cells and liver plasma membranes. Thymosin alpha 1 was 160 and 6250 times less potent that VIP at inhibiting [125I]VIP binding to blood mononuclear cells and liver plasma membranes, respectively. Thymosin alpha 1 (10(-10) to 10(-7) M) was weak in stimulating adenylate cyclase activity. Its efficacy is about 25% and 27% that of native VIP in blood mononuclear cells and liver plasma membranes, respectively. Thymosin alpha 1 may behave as a partial VIP agonist in rat.
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D004789:Enzyme Activation; D008099:Liver / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism; D051381:Rats; D011964:Receptors, Gastrointestinal Hormone / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives* / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D013947:Thymosin; D000262:Adenylyl Cyclases; D000077596:Thymalfasin