The influence of insulin, triiodothyronine (T3) and insulin-like growth factor-I (IGF-1) on the differentiation of preadipocytes in serum-free cultures of pig stromal-vascular cells.
Adipose tissue stromal-vascular (S-V) cells were obtained from 1-d-old pigs by enzymatic digestion and then grown to confluence (1 to 4 d) in 10% fetal bovine serum. Cultures then were shifted to serum-free media for 7 d. One and 50 nM insulin with transferrin (5 micrograms/ml) significantly increased (P less than .05) the cytodifferentiation of preadipocytes in serum-free cultures of S-V cells compared with control cultures (no hormones). Fifty nanomolar and 1 microM insulin with transferrin increased the specific activity of glycerol-phosphate dehydrogenase (GPDH) and the soluble protein levels of S-V cultures compared with control cultures. Ten nanomolar insulin-like growth factor-1 (IGF-1) increased (P less than .05) GPDH specific activity, soluble protein and preadipocyte cytodifferentiation compared with control cultures. Triiodothyronine (T3) supplementation (2 to 10 nM) increased (P less than .05) GPDH specific activity and increased lipid droplet size in preadipocytes compared with control cultures (no T3 but with insulin and transferrin). Cytodifferentiation of preadipocytes and soluble protein levels were not enhanced by T3 supplementation. Furthermore, T3 did not influence any parameters when added to S-V cultures that did not contain insulin. These data demonstrate that physiological levels of insulin or IGF-I can stimulate porcine preadipocyte differentiation in the absence of other hormones or growth factors.
Hausman
G J
GJ
U.S. Department of Agriculture, Athens, GA 30613.
D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D000818:Animals; D002452:Cell Count / Q000662:veterinary; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D012643:Selenium / Q000494:pharmacology; D013002:Somatomedins / Q000494:pharmacology*; D013552:Swine / Q000502:physiology*; D014168:Transferrin / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology*
D003470:Culture Media; D007328:Insulin; D013002:Somatomedins; D014168:Transferrin; D014284:Triiodothyronine; D007334:Insulin-Like Growth Factor I; D005993:Glycerolphosphate Dehydrogenase; D012643:Selenium