Studies on the changes in activities of bovine preadipocyte proliferation and differentiation during growth

(1)本研究旨在研究日本乌鱼生长过程中不同脂肪库脂肪细胞大小的变化，并确定脂肪组织细胞构成与饲料的关系。结果表明，饲料对特定年龄的某些脂肪组织的脂肪细胞大小有影响。(2)本文研究了噻唑烷二酮（thiazolidinedione）对牛卫星细胞成肌和转分化的调控作用。从成年肉牛的骨骼肌中获得卫星细胞。通过测定甘油-3-磷酸脱氢酶（GPDH）活性来评估卫星细胞向脂肪细胞的转分化。肌分化通过测量肌肌酸激酶（MCK）活性来评估。噻唑烷二酮不影响牛卫星细胞的GPDH和MCK活性。总之，牛卫星细胞不太可能转分化为脂肪细胞。(3)本研究的目的是阐明调控基质血管细胞分化的因素，来源于牛脂肪组织。维生素A抑制脂肪细胞分化。另一方面，维生素C和噻唑烷二酮增强了从脂肪组织分离的牛前脂肪细胞的分化。添加锌可促进牛前脂肪细胞的分化。一氧化氮（NO）代谢产物的浓度下降，通过添加锌到培养基中。NO供体（NOC 18）抑制GPDH活性，NOS抑制剂（L-NAME）增加GPDH活性。结果表明，NO旁分泌抑制脂肪细胞的分化，锌通过抑制牛前脂肪细胞NO的产生促进脂肪细胞的分化。从这些数据来看，营养控制牛肉大理石花纹是可能的。

(1) This research was undertaken to study changes in adipocyte size in different fat depots of Japanese Black (Wagyu) during growth, and to determine the relationship between adipose tissue cellularity and feed. We demonstrated that fat cell size of some adipose tissues in specific age were affected by feed.(2) The regulation of myogenesis and transdifferentiation of bovine satellite cells by thiazolidinedione that is a specific ligand for PPAR γ, were investigated in vitro. Satellite cells were obtained from the skeletal muscle of adult beef cattle. Transdifferentiation of satellite cells into adipocytes was assessed by the measurement of glycerol-3-phosphate dehydrogenase (GPDH) activity. Myogenic differentiation was evaluated by the measurement of muscle creatine kinase (MCK) activity. Thiazolidinedione affected neither GPDH nor MCK activity of bovine satellite cells. In conclusion, it is unlikely that bovine satellite cells can undergo transdifferentiation into adipocytes.(3) The purpose of this study was to clarify the factors which regulate differentiation in stromal-vascular cells Ioriginated from bovine adipose tissue. Vitamin A inhibited adipocyte differentiation. Vitamin C and thiazolidinedione, on the other hand, enhanced differentiation of bovine preadipocyte isolated from adipose tissue. The differentiation of bovine preadipocytes was promoted by the addition of zinc. Nitric oxide (NO) metabolites concentration was decreased by the addition of zinc into the medium. A NO donor (NOC1 8) suppressed GPDH activity, and a NOS inhibitor (L-NAME) increased GPDH activity. These results suggested that NO paracrinically inhibited adipocyte differentiation, and zinc promoted adipocyte differentiation through inhibiting NO production in bovine preadipocytes. From these data, it is possible that nutritional manipulations control beef marbling.