> Following abstracts describe TCDD's affect on intestines of monkeys,
> mice and worms.
Endocrine disruptive effects of polychlorinated aromatic hydrocarbons
on intestinal cholecystokinin in rats.
The ubiquitous and persistent nature of polychlorinated aromatic
hydrocarbons (PCAHs) in our environment and the risk of exposure to
PCAHs have provoked concern over their potential toxicity. In humans,
exposure to PCAHs is aimed chiefly at epithelial cells residing in the
intestinal mucosa, because oral intake of contaminated food is a major
source of PCAHs. The purpose of this study, therefore, was to examine
the effects of chronic exposure to various PCAHs [i.e. 2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran
(PeCDF), 3,3',4,4',5-pentachlorobiphenyl (PCB-126), and 2,2'4,4'5,5'-
hexachlorobiphenyl (PCB-153)], given alone or as mixtures, on
intestinal cholecystokinin (CCK) peptide and messenger RNA levels. We
show that chronic PCAH treatment significantly lowers intestinal
levels of stored CCK peptide. Intestinal CCK messenger RNA levels are
not affected. In addition, 3,3',4,4',5-pentachlorobiphenyl treatment
increased intestinal insulin-like growth factor-binding protein-3
levels in a dose-related manner. Acute 2,3,7,8-tetrachlorodibenzo-p-
dioxin treatment of intestinal CCK cells lowered levels of CCK-
processing enzymes (i.e. prohormone convertase-1 and -2). Together,
these data indicate that PCAHs may decrease intestinal levels of
stored CCK peptide by affecting the intestinal insulin-like growth
factor system and CCK processing. PMID: 10919282
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