Fascioliasis: nitrogen balance studies and the disposition of excessive proline in rats

Nitrogen balance studies were conducted and the results compared between rats infected with Fasciola hepatica and uninfected rats as follows: Rats with 90 to 100 day infections were randomly selected and then matched by weight to uninfected controls. All rats were then fed a 6% protein diet for 3 days. Nitrogen balance data indicated that infected rats excreted significantly higher urinary nitrogen than the healthy ones. As large quantities of proline were known to be released into the host in fascioliasis it was suggested that the excessive proline might cause depressed nitrogen balance. In view of this possibility and because any pathological effects of the excessive proline would likely be most apparent in the organs involved in its handling, a proline disposition study was carried out. For this part of the study, the levels of the proline in various regions of the gut, the urine, the feces and the portal blood of both infected and control rats were measured and compared. Proline levels were found to be elevated in portal blood, duodenal contents, colonic contents, urine and feces.