Metabolic relationship of exogenous phospholipids and phosphate to biliary phospholipids

Abstract

To study the metabolic relation between exogenous phosphorus and biliary phospholipids, P³²-orthophosphate and P³²-labeled phospholipids were injected into the duodenum through the distal end of the severed common duct of the rat while bile was collected from the proximal end of the severed duct. Following the administration of biosynthesized P³²-labeled phospholipids, P³² appeared in the bile within 3 hours, reached a maximum concentration in about 6 hours and then decreased gradually. About 5–6% of the total absorbed radioactivity was recovered. Following the administration of labeled orthophosphate, P³² appeared in the bile more rapidly, within 30 minutes, and reached a maximum concentration after about 4 hours. Specific activity of organic phosphorus in bile reached its peak from the 4th to the 12th hour. About 2% of the total absorbed radioactivity was recovered. Following the administration of radioactive bile obtained from rats given high radioactive inorganic orthophosphate intraperitoneally, the pattern of P³² excretion in bile was similar to that of P³²-labeled phospholipids administration. After intravenous administration of labeled phospholipids with sodium cholate as an emulsifer, P³² appeared in the bile immediately.