A PREADIPOCYTE CLONAL LINE FROM BOVINE INTRAMUSCULAR ADIPOSE-TISSUE -NONEXPRESSION OF GLUT-4 PROTEIN DURING ADIPOCYTE DIFFERENTIATION

A clonal bovine intramuscular preadipocyte (BIP) line has been establi shed from the intramuscular white adipose tissue of the M. longissimus thoracis in each of three Japanese Black cattle. Exponentially growin g BIP cells exhibited a fibroblastic appearance. Adipocyte differentia tion was initiated by treating confluent BIP cells with differentiatio n medium containing insulin and dexamethasone. Small lipid droplets ap peared 5-6 days after stimulation and occupied a large fraction of the cell volume at 10 days and beyond. During the adipose conversion, the incorporation of acetate to the cells gradually increased by 10-fold and reached a maximum at day 5. However, incorporation of glucose incr eased only S-folds prior to this conversion, even though GLUT-1 level increased by 13-fold at day 7. GLUT-4 on the other hand, was not detec ted during the course of differentiation. These results suggested that adipose tissue metabolisms in ruminants were different from that of n on-ruminants. (C) 1995 Academic Press, Inc.