Hormonal effects on proliferation of adipocyte precursor cells isolated from chicken enbryos

Abstract

Influence of glucagon (GLU), insulin (IN), growth hormone (GH) , and triiodothyronine (T3) on proliferation of chicken adipocyte precursor cells was examined. Adipocyte precursor cells were isolated from subcutaneous and f emoral adipose depots from 18-day embryos using collagenase digestion. The digest was filtered through nylon screens to remove cell aggregates, and stromal-vascular cells were further separated from mature adipocytes by centrifugation. Medium 199 supplemented with antibiotics and fetal bovine serum (FBS) was used to support growth of adipocyte precursors. Cells multiplied to conf luency and matured into lipid droplet-containing adipocytes in culture. Confuency from initial plating density ( 104 cel 1S/CM2) was achieved by 6 to 7 days of incubation. Multiplication of fibroblastlike cells and adipocyte precursors was proportional to the concentration of FBS added to medium. Cells did not proliferate in serum-free media without hormone treatment. High concentrations of a mixture of bovine and porcine glucagon (MGLU, [ ]31.6 ng/mL) and T3 (2:1000 ng/mL) alone significantly (P<.05) stimulated cell proliferation. High concentrations of bovine insulin (bIN) (2:10' ng/mL) increased cell sensitivity to T3-stimulated cell proliferation (P<.Ol) although lower concentrations of bIN did not. Chicken glucagon (cGLU), porcine growth hormone (pGH) and bIN alone failed to stimulate cell multiplication. Several combinations of hormones did not increase proliferation above values observed when a single hormone was used. Porcine GH with bIN failed to stimulate cell proliferation. Combinations of MGLU (2 X 103 ng/mL) and bIN (105ng/mL) stimulated cell growth (P<.Ol), but stimulation wasnot significantly different from values achieved with MGLUalone. Addition of T3-treated cells to pGH did not increase responsiveness of cells to the effect T3 alone. FBS had a greater impact on cell multiplication than any examined hormone treatment (P<.Ol).