title: Effects of castration on expression of lipid metabolism genes in the liver of korean cattle.
abstract: Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cattle, resulting in improved beef quality. However, little is known about the metabolic adaptations in the liver following castration. To understand changes in lipid metabolism following castration, hepatic expression levels of lipid metabolism genes were compared between Korean bulls and steers. Steers had higher (p<0.001) hepatic lipids contents and higher (p<0.01) mRNA levels of lipogenic acetyl-CoA carboxylase. This differential gene expression may, in part, contribute to increased hepatic lipid content following the castration of bulls. However, we found no differences in the hepatic expression levels of genes related to triglyceride synthesis (mitochondrial glycerol-3-phosphate acyltransferase, diacylglycerol O-acyltransferase 1 and 2) and fatty acid (FA) oxidation (carnitine palmitoyltransferase 1A, C-4 to C-12 straight chain acyl-CoA dehydrogenase, very long chain acyl-CoA dehydrogenase) between bulls and steers. No differences in gene expression for very-low-density lipoprotein (VLDL) secretion, including apolipoprotein B mRNA and microsomal triglyceride transfer protein (MTTP) protein, were observed in the liver although MTTP mRNA levels were higher in steers compared to bulls. In conclusion, FA synthesis may contribute to increased hepatic lipid deposition in steers following castration. However, hepatic lipid metabolism, including triglyceride synthesis, FA oxidation, and VLDL secretion, was not significantly altered by castration. Our results suggest that hepatic lipid metabolism does not significantly contribute to increased body fat deposition in steers following castration.
authors.affiliation: Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea ; Institute of Green Bio Science Technology, Pyeungchang 232-916, Korea.
authors.forename: Myunggi
authors.initials: M
authors.lastname: Baik
authors.affiliation: Department of Molecular Biotechnology, Chonnam National University, Gwangju 500-757, Korea.
authors.forename: Trang Hoa
authors.initials: TH
authors.lastname: Nguyen
authors.affiliation: National Institute of Animal Science, RDA, Suwon 441-706, Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Jeong
authors.affiliation: Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea ; Institute of Green Bio Science Technology, Pyeungchang 232-916, Korea.
authors.forename: Min Yu
authors.initials: MY
authors.lastname: Piao
authors.affiliation: Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea ; Institute of Green Bio Science Technology, Pyeungchang 232-916, Korea.
authors.forename: Hyeok Joong
authors.initials: HJ
authors.lastname: Kang
keywords: Bulls; Gene Expression; Korean Cattle; Liver; Steers