INHIBITION OF INTESTINAL GLUCOSE-ABSORPTION IN RATS TREATED WITH 2,3,7,8-TETRACHLORODIBENZO-PARA-DIOXIN

Male Sprague-Dawley rats were injected with either 125-mu-g 2,3,7,8-te trachlorodibenzo-p-dioxin (TCDD)/kg or vehicle (pair-fed and ad libitu m-fed controls). Transfer of water, electrolytes and D-glucose as well as fats of a tracer dose of the non-metabolizable radioactive marker 3-0-methyl-D-[U-C-14]glucose was studied in isolated perfused jejunal segments 1, 2, 7, and 21 d after treatment (TCDD-treated and pair-fed control rats) and after 26 d in ad libitum-fed controls. TCDD-treated rats demonstrated reduced feed consumption and loss of body weight. Ac tive intestinal absorption of glucose was significantly inhibited 30 a nd 22% compared to pair-fed controls, respectively 2 and 7 d after TCD D treatment. After 21 d the inhibition (14%) was less significant. The re were no differences in glucose transfer between severely starved pa ir-fed controls (body weights 370 +/- 26 g) and ad libitum-fed rats (b ody weights 512 +/- 15 g). Water absorption and transfer of sodium and calcium was not influenced by TCDD treatment. However, a significant increase of potassium transfer was observed in parallel with impaired glucose absorption. The uptake of 3-0-methylglucose into mucosal tissu e was not impaired, whereas the transfer to the serosal side was signi ficantly inhibited by 30-60% compared to pair-fed as well as ad libitu m-fed animals from day 2 until the end of the experiment. These result s suggest that TCDD is involved in an inhibition of glucose transport at the basolateral membrane.