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Intestinal apoprotein biosynthesis: alpha-1-antitrypsin identified as a constituent of rat lymph chylomicrons

Thesis/Dissertation ·
OSTI ID:6281495

Apolipoproteins synthesized in the intestine can serve as a source of constituents for plasma lipoproteins and play an important role in the pathways of lipoprotein formation, interconversion, and catabolism. In the present study, apolipoproteins synthesized by the intestine were identified in mesenteric lymph following intraduodenal administration of lipid and (/sup 14/C)-leucine to rats. The study was undertaken to assess differences in the rate of appearance of newly synthesized apolipoproteins into chylomicron and VLDL particles of rat mesenteric lymph and to determine if there is a sex-related influence on this process. Examination of qualitative and quantitative differences in apolipoprotein profiles, (/sup 14/C)-leucine labeling patterns, and the specific activities of the individual apolipoproteins secreted with either chylomicrons or VLDL distinguish the two particles and their pathways of assembly. A protein of molecular weight 54,000 daltons was recovered with the chylomicrons. The protein was shown to be synthesized by rat liver hepatocytes, and immunoprecipitation studies with rat intestinal cells incubated with /sup 35/S-methionine included this organ as a source of alpha-1-antitrypsin.

Research Organization:
George Washington Univ., Washington, DC (USA)
OSTI ID:
6281495
Country of Publication:
United States
Language:
English