Purification and partial characterization of a mitogenic protein released from preadipocytes of massively obese subjects.
A protein released into the culture medium by omental preadipocytes of massively obese persons, which stimulates the replication of rat perirenal preadipocytes, has been purified to a high degree. By gel filtration chromatography, the molecular mass of the mitogenic protein was approximately 66,000 daltons (Da), while on sodium dodecyl sulfate - polyacrylamide gel electrophoresis, two subunits were obtained, relative masses (Mr) of approximately 31,000 and approximately 35,000. The isoelectric point of the approximately 66,000 Da entity was 5.6 +/- 0.2. By specific radioreceptor assay, the purified protein was related to epidermal growth factor and transforming growth factor alpha. It was not related to insulin-like growth factors I and II by radioimmunoassay and radioreceptor assay. We propose that the approximately 66,000 Mr protein, and other mitogenic proteins released by preadipocytes from massively obese persons, act through paracrine-autocrine mechanisms and may play a role in the development of the hyperplasia of enlarged fat cells characteristic of massive corpulence.
Roncari
D A
DA
Institute of Medical Science, University of Toronto, Ont., Canada.
Thompson
C E
CE
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003429:Cross Reactions; D005260:Female; D006133:Growth Substances / Q000276:immunology / Q000302:isolation & purification* / Q000494:pharmacology; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D051381:Rats; D011919:Rats, Inbred Strains; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*
D006133:Growth Substances