Comparison of the rates of proliferation of adipocyte precursor cells derived from two lines of chicken which differ in their rates of adipose tissue development.

1. Putative adipocyte precursor cells were isolated from the white adipose tissue of young broiler and layer chickens and cultured in vitro. 2. The cells from both sources were shown to have the characteristics of adipocyte precursor cells. On reaching confluence, lipoprotein lipase activity was induced and the cells from both strains accumulated large amounts of lipid in the presence of chicken serum. 3. Measurement of cell number over time in culture and calculation of cell doubling times showed that cells from broilers proliferated at a faster rate than those derived from layer-strain chickens. This was the case whether primary or secondary cell cultures were used. Primary cultures of broiler cells had a doubling time of 22 h versus 39 h for layer cells. 4. The contribution of such a difference in proliferative rate to the differential rate of adipose tissue growth between broiler and layer strains observed in vivo is discussed.