Abstract
1.
1. The metabolism of glucose, glutamine and ketone-bodies was studied in the small intestine of rats after 5 days of hyperthyroidism.
2.
2. Portal-drained visceral bloodflow increased by 20.1% (
P < 0.05) in hyperthyroid rats and was accompanied by a decrease in the arteriovenous concentration difference of glutamine (25.7%,
P < 0.05), glutamate (22.0%,
P < 0.05), alanine (20.9%,
P < 0.05) and ammonia (20.6%,
P < 0.05) and an increase in that of glucose (27.2%,
P < 0.05), lactate (28.9%,
P < 0.05) and ketone-bodies (163.2%,
P< 0.001).
3.
3. The gut of hyperthyroid rats showed increased rates of extraction of glucose, lactate and ketone-bodies.
4.
4. Enterocytes isolated from hyperthyroid rats showed increased rates of utilization of glucose and ketone-bodies but that of glutamine were decreased.
5.
5. The maximal activities of hexokinase, 6-phosphofructokinase, pyruvate kinase, citrate synthase and oxoglutarate dehydrogenase were increased (by 13.7–36.2%) in intestinal mucosal scrapings of hyperthyroid rats, whereas the activity of glutaminase was decreased (22.1–31.4%).
6.
6. It is concluded that hyperthyroidism increases the rates of utilization of glucose and ketone-bodies but decreases that of glutamine (both
in vivo and
in vitro) by the epithelial cells of the small intestine.