Utilization of intestinal triglyceride-rich lipoproteins in mammary gland of cows.
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.
Uchide
T
T
Department of Veterinary Medical Sciences, Graduate School of Agricultural and Life Sciences, University of Tokyo, Japan.
Onda
K
K
Bonkobara
M
M
Thongsong
B
B
Matsuki
N
N
Inaba
M
M
Ono
K
K
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*
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