Intestinal absorption of polyenephosphatidylcholine in man

Area of Science:

• Biochemistry
• Human Physiology
• Lipid Metabolism

Background:

• Phosphatidylcholine (PC) is a major component of cell membranes and lipoproteins.
• Understanding the metabolic fate of dietary PC is crucial for comprehending lipid absorption and transport.

Purpose of the Study:

• To investigate the absorption and metabolic fate of orally administered dilinoleoglycerophosphocholine in humans.
• To determine the distribution of absorbed phosphatidylcholine (PC) within plasma lipoproteins.

Main Methods:

• Oral administration of 3H/14C-labeled dilinoleoglycerophosphocholine to five patients.
• Quantification of isotope absorption from the intestine.
• Analysis of radioactivity distribution in blood components, including plasma and lipoproteins (HDL, apoB-containing).

Main Results:

• Over 90% of both 3H (choline) and 14C (linoleic acid) isotopes were absorbed.
• Plasma PC showed a higher 3H/14C ratio than oral PC, suggesting hydrolysis before absorption.
• Absorbed PC was preferentially incorporated into the high-density lipoprotein (HDL) fraction of plasma.

Conclusions:

• Dietary phosphatidylcholine (PC) is efficiently absorbed, likely after hydrolysis to lysolecithin.
• The high-density lipoprotein (HDL) fraction is a primary destination for absorbed PC in the plasma.
• This preferential incorporation into HDL may influence lipoprotein metabolism and function.