Human immunoglobulin M stimulates adipocyte lipogenesis.
In view of our recent demonstration that human immunoglobulin G (IgG) and its Fc moiety exert a stimulatory effect on lipogenesis by adipocytes, we have examined the possibility that human immunoglobulin M (IgM) may induce a similar effect upon adipocytes. Three IgM preparations, obtained from patients with Waldenstrom's macroglobulinemia, and a commercial preparation produced consistent dose-related stimulation of lipogenesis by adipocytes. This stimulation was additive to, and greater than, the maximal stimulation produced by insulin; it also neutralized completely by preincubation with mu-chain specific anti-IgM antiserum but not by an excess of anti-insulin antiserum. Similar stimulation of adipocyte lipogenesis was observed with (Fc)5 fragments prepared from IgM fractions. Therefore, IgM exerts a stimulatory effect upon adipocyte lipogenesis similar to that of IgG; this effect is probably mediated through a putative Fc receptor on the adipocyte membrane.
D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000494:pharmacology; D007075:Immunoglobulin M / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D008055:Lipids / Q000096:biosynthesis*; D008297:Male; D051381:Rats
D007141:Immunoglobulin Fc Fragments; D007075:Immunoglobulin M; D007328:Insulin; D008055:Lipids