17-beta-estradiol increases mitogenic activity of medium from cultured preadipocytes of massively obese persons

Having reported that omental preadipocytes from massively obese persons release into the culture medium proteins mitogenic for preadipocytes, this study aimed to determine whether estrogens contribute to the production of these factors. Sub-cultured omental preadipocytes from 13 massively obese women were grown in the presence or absence of 17-beta-estradiol, and during the last 24 h the conditioned medium was prepared in the absence of serum. Media from cells of 8 of 13 subjects contained significantly higher mitogenic activity when grown in the presence of 17-beta-estradiol. 17-Alpha-estradiol was not effective. The bioassay system involved rat perirenal preadipocytes, since these have been well characterized. Partial purification by gel filtration chromatography indicated that the estrogen-dependent factors had Mr greater than 250,000 and approximately 30,000. Thus, estrogens might contribute to the development of massive obesity in genetically susceptible subjects by promoting the production of paracrine/autocrine principles by adipose cells.