Savaiano D A, Ho C Y, Chu V, Clifford A J
J Nutr. 1980 Sep;110(9):1793-804. doi: 10.1093/jn/110.9.1793.
One experiment was conducted in which radioactively labeled purine bases (adenine, guanine, hypoxanthine and xanthine) were individually given intravenously to young adult rats 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 adenine was measured in experiment 2. A third experiment measured the recoveries of radioactivity from oral and intravenous adenine 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 adenine were compared in a fourth experiment. When purines were given intravenously, significantly more of the administered radioactivity was recovered in urine from rats given guanine, hypoxanthine or xanthine compared with those given adenine. 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 adenine 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 adenine was allantoin. The absorption of individual purines from isolated rat gut sacs was evaluated in a fifth experiment. A significant proportion of unaltered adenine crossed the mucosal to serosal barrier of intestinal sacs whereas unaltered guanine, hypoxanthine or xanthine did not cross into the serosal fluid. These results show that the intestinal metabolism of dietary adenine is uniquely different from that of guanine, hypoxanthine or xanthine.
进行了一项实验，将放射性标记的嘌呤碱基（腺嘌呤、鸟嘌呤、次黄嘌呤和黄嘌呤）分别静脉注射给成年幼鼠，并在接下来的24小时结束时测量尿液、肠道、肠道内容物和肝脏中放射性的恢复情况。实验2测量了口服和静脉注射腺嘌呤后放射性的总恢复情况。第三个实验测量了口服和静脉注射腺嘌呤后在比实验1更多种类的组织和器官中放射性的恢复情况。在第四个实验中比较了口服和静脉注射腺嘌呤代谢的尿液终产物的化学特性。当静脉注射嘌呤时，与给予腺嘌呤的大鼠相比，给予鸟嘌呤、次黄嘌呤或黄嘌呤的大鼠尿液中回收的放射性给药量明显更多。尿液中放射性回收率更高与组织中回收率更低相关。与口服给药相比，静脉注射腺嘌呤的放射性更大比例被纳入所有身体组织，这在腺组织和淋巴组织中最为明显。口服和静脉注射腺嘌呤的主要尿液终产物都是尿囊素。在第五个实验中评估了从分离的大鼠肠囊中对单个嘌呤的吸收情况。相当比例的未改变的腺嘌呤穿过肠囊的黏膜到浆膜屏障，而未改变的鸟嘌呤、次黄嘌呤或黄嘌呤没有进入浆膜液。这些结果表明，膳食腺嘌呤的肠道代谢与鸟嘌呤、次黄嘌呤或黄嘌呤的肠道代谢有独特的不同。
