Analysis of a model to describe lead transport by the small intestine


Investigations into the mechanism of lead transport across the rat small intestine were conducted using the in vitro everted sac technique. The data obtained were used to construct a model which could competently rationalise some of the reported observations in the literature concerning intestinal lead transport. The model comprises of two individual processes acting in concert. A large rapid adsorption of lead onto the intestinal tissue surface; and a concurrent slow passive diffusion of lead cations across the intestinal epithelium. The presence of methylxanthines, which diminish the size of the intercellular channels, were found to decrease the rate of lead cation transport, and indicated a paracellular route for lead transport. Certain metal cations compete with lead for transport via the paracellular route and hence decrease its rate of transit. Other metal cations increase the tissue binding of lead by a process of coprecipitation, and may ultimately increase the entry of lead into the body. Chelated lead species exhibit different kinetic characteristics to that of the lead cation. The data suggests that chelation accelerates lead absorption, probably by the utilisation of a transcellular transport route. The studies indicate why, under normal conditions, only a small percentage of lead is absorbed, and also suggest the manner by which larger arrounts of lead may gain entry into the body.

Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
Additional Information: (c) Maurice John Coogan, 1982. Maurice John Coogan asserts their moral right to be identified as the author of this thesis. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without appropriate permission or acknowledgement. If you have discovered material in Aston Publications Explorer which is unlawful e.g. breaches copyright, (either yours or that of a third party) or any other law, including but not limited to those relating to patent, trademark, confidentiality, data protection, obscenity, defamation, libel, then please read our Takedown Policy and contact the service immediately. Department: Chemistry
Institution: Aston University
Uncontrolled Keywords: Intestinal Lead Absorption,Paracellular Transport,Adsorption,Coprecipitation
Last Modified: 28 Jun 2024 07:19
Date Deposited: 13 Jan 2011 11:53
Completed Date: 1982-06
Authors: Coogan, Maurice J.

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