title: Utilization of intestinal triglyceride-rich lipoproteins in mammary gland of cows.
abstract: Elution profiles of total lipoproteins, apolipoprotein B (apoB) concentrations in lipoproteins, and plasma triglyceride (TG) levels were examined in early-, late-, and non-lactating cows. Additionally, arteriovenous (A-V) differences were also measured to elucidate the uptake of TG and apoB-containing lipoproteins in mammary gland. Non-lactating cows showed three major peaks corresponding to triglyceride-rich lipoprotein (TRL), low density lipoprotein (LDL), and high density lipoprotein (HDL) fraction, whereas both early- and late-lactating cows revealed two peaks corresponding to TRL and HDL. The peak area of TRL in early- and late-lactating cows were significantly (p < 0.05) smaller than that in non-lactating cows. The plasma TG levels and apoB-48 concentrations of TRL in early- and late-lactating cows were also significantly (p < 0.01) lower. Furthermore, early lactating cows showed significantly (p < 0.05) larger A-V differences in both plasma TG and apoB-48 concentration of TRL than those in late- and non-lactating cows. These results suggested that TG in exogenous (intestinal) TRL was utilized for milk fat synthesis in lactating mammary gland of cows by the receptor-mediated uptake.
authors.affiliation: Department of Veterinary Medical Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uchide
authors.forename: K
authors.initials: K
authors.lastname: Onda
authors.forename: M
authors.initials: M
authors.lastname: Bonkobara
authors.forename: B
authors.initials: B
authors.lastname: Thongsong
authors.forename: N
authors.initials: N
authors.lastname: Matsuki
authors.forename: M
authors.initials: M
authors.lastname: Inaba
authors.forename: K
authors.initials: K
authors.lastname: Ono
mesh_terms: D000818:Animals; D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B / Q000097:blood / Q000502:physiology*; D002417:Cattle / Q000502:physiology*; D002850:Chromatography, Gel / Q000662:veterinary; D002914:Chylomicrons / Q000097:blood; D005260:Female; D007422:Intestines / Q000502:physiology; D007774:Lactation / Q000502:physiology*; D008074:Lipoproteins / Q000097:blood; D008075:Lipoproteins, HDL / Q000097:blood; D053419:Lipoproteins, IDL; D008077:Lipoproteins, LDL / Q000097:blood; D008321:Mammary Glands, Animal / Q000502:physiology*; D008892:Milk / Q000378:metabolism; D014280:Triglycerides / Q000097:blood / Q000378:metabolism*
chemical_list: D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B; D002914:Chylomicrons; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D053419:Lipoproteins, IDL; D008077:Lipoproteins, LDL; D014280:Triglycerides