Gastrointestinal absorption of Ochratoxin A

Barrowman, Gwynedd (1993) Gastrointestinal absorption of Ochratoxin A. Masters thesis, Memorial University of Newfoundland.

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Abstract

The mycotoxin Ochratoxin A (OTA), is a widespread contaminant of cereals, beans and meat products. Its solubility in the aqueous phase depends on ionization of the phenolic hydroxyl group whose pK, was found to be 7.05. Earlier researchers have demonstrated the importance of the portal venous route in OTA absorption. Absorption in the presence of lipids is of interest because lipids form a significant proportion of the diet in countries where OTA contamination occurs. When OTA was administered to conscious rats in corn oil rather than in sodium bicarbonate, the lymphatic route played a greater role in the transport of absorbed OTA. In the absence of bile, OTA transport in lymph was not increased even in the presence of corn oil, suggesting that OTA handling by the lymphatic route depends on micellar solubilization in mixed bile salt/lipid micelles. When carried in lymph, OTA reaches the general circulation without being subjected to "first-pass" hepatic metabolism. -- Key words: ochratoxin A; nephrotoxin; lymphatic transport

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