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The current study was undertaken to determine the effects of age and feeding level of the concentrates on lipogenesis of adipose tissue and adipocyte size in the Hanwoo bulls. A total of 48 bulls was allocated into 3 feeding groups, 85% 100%, 115% of the requirement for Hanwoo cattle. Four animals per feeding level were killed at 15, 18, 24, 30 months of age for the measurement of lipogenesis and adipocyte size. Lipogenesis was measured with subcutaneous, intermuscular adipose tissue explants in culture by the amount of acetate or glucose converted into the total lipid and adipocyte diameters were measured with subcutaneous, intermuscular, and perirenal fat tissues at each slaughtering age. Initially, we measured the effect of insulin on lipogenesis of Hanwoo adipose tissue to establish an optimal condition for measuring lipogenesis. Insulin had no effect on lipogenesis. As the bulls get older, lipogenesis from acetate was reduced and similar trend was found for glucose. Lipogenesis from acetate of subcutaneous adipose tissue was higher than that of intermuscular adipose tissue. However, there was no significant difference in lipogenesis from glucose between the two adipose tissues. Adipocyte diameter was continuously increased from 15 to 30 months of age in the Hanwoo bulls. Adipocytes from perirenal adipose tissue were bigger than those from subcutaneous or intermuscular adipose tissues. Feeding level of concentrates did not affect either lipogenesis or adipocyte size.
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