IGF-I inhibits apoptosis induced by serum withdrawal, but potentiates TNF-alpha-induced apoptosis, in 3T3-L1 preadipocytes

Abstract

We have previously shown that human preadipocytes in primary culture undergo apoptosis in response to serum deprivation and addition of tumour necrosis factor alpha (TNF-alpha), and have proposed that regulation of preadipocyte apoptosis in vivo may contribute to the overall control of adipose mass. In the present study we have investigated both pro- and anti-apoptotic factors, and the signalling pathways by which they act, in murine 3T3-L1 preadipocytes. Apoptotic indices (fraction of cells undergoing apoptosis) were determined by microscopic examination of acridine orange-stained cells, fluorescence-activated cell sorting of propidium iodide-stained cells, or phase-contrast video microscop..