Soret B, Lee H J, Finley E, Lee S C, Vernon R G
Hannah Research Institute, Ayr KA6 5HL, UK.
J Endocrinol. 1999 Jun;161(3):517-24. doi: 10.1677/joe.0.1610517.
Factors regulating the differentiation of sheep subcutaneous and abdominal (omental or perirenal) preadipocytes from foetal lambs, suckling lambs and fattening sheep have been investigated using a serum-free cell culture system. Differentiation was assessed by changes in the activity of the enzyme glycerol 3-phosphate dehydrogenase. Insulin or IGF-I was essential for differentiation. Dexamethasone, a lipid supplement (Excyte) and the thiazolidinedione, rosiglitazone (BRL 49653) (a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonist) all enhanced preadipocyte differentiation, whereas fibroblast growth factor and GH were inhibitory. The most effective combination was insulin, triiodothyronine, dexamethasone and rosiglitazone. Under suboptimal conditions, preadipocytes from fattening sheep differentiated less well than cells from suckling and foetal lambs. Also, under suboptimal conditions, abdominal preadipocytes did not differentiate as well as subcutaneous preadipocytes. However, age and depot differences were minimised when cells were cultured with insulin, triiodothyronine, rosiglitazone and either dexamethasone or lipid. The results suggest that variation in the ability to produce the natural ligand for PPAR-gamma contributes to depot- and age-specific differences in the ability of preadipocytes to differentiate.
利用无血清细胞培养系统，对调节胎羊、哺乳羔羊和育肥羊的皮下及腹部（网膜或肾周）前体脂肪细胞分化的因素进行了研究。通过检测3-磷酸甘油脱氢酶的活性变化来评估分化情况。胰岛素或胰岛素样生长因子-I（IGF-I）是分化所必需的。地塞米松、一种脂质补充剂（Excyte）和噻唑烷二酮类药物罗格列酮（BRL 49653，一种过氧化物酶体增殖物激活受体γ（PPAR-γ）激动剂）均能增强前体脂肪细胞的分化，而成纤维细胞生长因子和生长激素则具有抑制作用。最有效的组合是胰岛素、三碘甲状腺原氨酸、地塞米松和罗格列酮。在次优条件下，育肥羊的前体脂肪细胞分化程度不如哺乳羔羊和胎羊的细胞。此外，在次优条件下，腹部前体脂肪细胞的分化程度不如皮下前体脂肪细胞。然而，当细胞与胰岛素、三碘甲状腺原氨酸、罗格列酮以及地塞米松或脂质一起培养时，年龄和部位差异会降至最低。结果表明，产生PPAR-γ天然配体能力的差异导致了前体脂肪细胞分化能力的部位和年龄特异性差异。
