Metabolism of orally and intravenously administered purines in XXXX .

@entity3625 @entity10043 @entity3624 @entity2774 @entity5536 @entity35
One experiment was conducted in which radioactively labeled @entity10043 bases ( @entity5536 , @entity2774 , @entity3625 and @entity3624 ) were individually given intravenously to young adult @entity35 and the recovery of radioactivity in urine and gut, gut content and liver was measured at the end of the next 24 hours. The total recovery of radioactivity from orally and intravenously administered @entity5536 was measured in experiment 2. A third experiment measured the recoveries of radioactivity from oral and intravenous @entity5536 in a wider variety of tissues and organs than in experiment 1. The chemical identities of the urinary end products of the metabolism or orally and intravenously administered @entity5536 were compared in a fourth experiment. When purines were given intravenously, significantly more of the administered radioactivity was recovered in urine from @entity35 given @entity2774 , @entity3625 or @entity3624 compared with those given @entity5536 . The greater recoveries of radioactivity in urine were associated with smaller recoveries in tissues. A larger proportion of intravenously compared to orally administered radioactivity from @entity5536 was incorporated into all body tissues, and this was most pronounced in glandular and lymphoid tissues. The primary urinary end product of both orally and intravenously administered @entity5536 was allantoin. The absorption of individual purines from isolated @entity35 gut sacs was evaluated in a fifth experiment. A significant proportion of unaltered @entity5536 crossed the mucosal to serosal barrier of intestinal sacs whereas unaltered @entity2774 , @entity3625 or @entity3624 did not cross into the serosal fluid. These results show that the intestinal metabolism of dietary @entity5536 is uniquely different from that of @entity2774 , @entity3625 or @entity3624 .
