Ramsay T G, White M E, Wolverton C K
Ohio State University, Columbus.
J Anim Sci. 1989 Sep;67(9):2452-9. doi: 10.2527/jas1989.6792452x.
The role of insulin-like growth factor I (IGF-1) in the development of the porcine preadipocyte was studied. Primary cultures of stromal-vascular cells (containing preadipocytes) were derived from s.c. adipose tissue of pigs at 1 d of age by enzyme digestion and centrifugation. Cells were cultured for a total of 15 d. Cells were exposed to IGF-1 at concentrations of 0, 5, 25 or 50 ng/ml medium during one of four time periods: d 1-15, d 1-5, d 13-15, or 4 h on d 15 of culture. IGF-1 had a mitogenic effect on cells during the first three time periods as determined by coulter counting. IGF-1 induced the enzymatic differentiation of porcine preadipocytes following exposure for either the entire 15 d of culture or for only 48 h (d 13-15) after confluency had been attained (d 5). Histochemically, lipid accumulation over time paralleled changes in enzyme activity. Incubation of IGF-1 with the cell cultures during the logarithmic phase of growth (d 1-5) or for 4 h on d 15 did not affect enzyme activity. These data indicate that IGF-1 can induce the differentiation of porcine preadipocytes after the cells leave the logarithmic phase of growth through action on post-confluent events.
研究了胰岛素样生长因子I（IGF-1）在猪前脂肪细胞发育中的作用。通过酶消化和离心从1日龄猪的皮下脂肪组织中获取基质血管细胞（含前脂肪细胞）的原代培养物。细胞共培养15天。在四个时间段之一将细胞暴露于浓度为0、5、25或50 ng/ml培养基的IGF-1中：培养第1 - 15天、第1 - 5天、第13 - 15天或培养第15天的4小时。通过库尔特计数确定，IGF-1在前三个时间段对细胞有促有丝分裂作用。在培养的整个15天或在达到汇合（第5天）后仅暴露48小时（第13 - 15天）后，IGF-1诱导猪前脂肪细胞的酶促分化。从组织化学角度看，随着时间推移脂质积累与酶活性变化平行。在生长对数期（第1 - 5天）或在第15天培养4小时期间将IGF-1与细胞培养物一起孵育不影响酶活性。这些数据表明，IGF-1可在细胞离开生长对数期后通过作用于汇合后事件诱导猪前脂肪细胞分化。
