Fat depot‐specific differences in leptin mRNA expression and its relation to adipocyte size in steers

Abstract

ABSTRACT This experiment was conducted to investigate leptin mRNA expression, adipocyte size, and their relationship in several adipose tissues of fattening steers. Subcutaneous, perirenal, intermuscular and intramuscular adipose tissues were collected from three crossbred steers (Japanese Black cattle X Holstein) aged 21 months. The mRNA level and adipocyte diameter were determined in these adipose tissues. The intramuscular adipose tissue had a lower leptin mRNA level than the intermuscular and perirenal adipose tissues ( P < 0.05). Leptin mRNA level was lower in the subcutaneous depot than in the intermuscular depot ( P < 0.05). Adipocyte diameter was larger in the intermuscular adipose tissue than in the subcutaneous and intramuscular adipose tissues ( P < 0.05). Leptin mRNA level was positively correlated with adipocyte diameter ( r 2 = 0.81, P < 0.05). These results suggest that the cattle have fat depot‐specific differences in leptin gene expression, which are a result of a difference in adipocyte size.