[The influence of the small intestine on the metabolism of 3-methylhistidine in the rat].

20 male adult Sprague-Dawley rats were fed exclusively parenterally. After achieving metabolic equilibrium they received a duodenoileostomy and subtotal resection leaving only 8-10% of the small gut. On the 1st pop. day the urinary 3-MH excretion rose to 1.5-1.7 of the preoperative level, but on the 12th-14th pop. day it fell again and was equal to the preoperative basal level. A control group of 10 rats undergoing a small gut anastomosis without resection yielded similar results. We conclude that the small gut source does not make a significant contribution to 24 h-urinary 3-MH excretion in the adult rat. The transient postoperative increase in urinary 3-MH excretion is probably due to post-injury metabolism.