The development of adipocytes in primary stromal-vascular culture of fetal pig adipose tissue.

Primary cultures of stromal-vascular cells of adipose tissue from fetuses at 70 and 110 days of gestation were evaluated as potential model systems for studies of fetal adipocyte differentiation and proliferation. In the cultures, fat cells developed as very discrete clusters. Fat cell cluster development was dependent on initial cell density and time. Histochemical analysis for NADP-dependent dehydrogenases revealed an age of donor effect. Similar levels of enzymes (malate and glucose-6-phosphate dehydrogenase) were apparent in fat cell clusters and stromal cells in cultures of cells from fetuses at 70 days of gestation. These enzymes were only present in fat cell clusters in cultures of cells from fetuses at 110 days of gestation. The distribution of histochemically detectable esterase activity was dependent on the cell density at time of analysis. In areas of high cell density, esterase was restricted to fat cell clusters whereas, both stromal cells and fat cells were esterase reactive in areas of low cell density. Omitting PMS from the dehydrogenase media revealed differences in enzyme reactions of cells grown on collagen-coated and uncoated glass surfaces. These studies demonstrate that primary cultures of stromal-vascular cells from 110-day-old fetuses would be a useful system to identify factors involved in adipocyte proliferation and differentiation.