von Engelhardt W, Hinderer S, Rechkemmer G, Becker G
Q J Exp Physiol. 1984 Jul;69(3):469-75. doi: 10.1113/expphysiol.1984.sp002833.
Total urea entry rate into the body pool and urea hydrolysis rate (transfer of endogenous urea into the total gastrointestinal (g.i.) tract) were obtained after single intravenous injections of [14C]urea and from renal urea excretion in sheep and goat. Secretion of endogenous urea into the colon was estimated from the appearance of urea N in the temporarily isolated and perfused colon. Rate of urea secretion into the colon was rather small (0.10-0.31 mmol . h-1). It was only 0.3-1.1% of urea entry rate, or 0.4-7% of urea hydrolysis rate. Urea secretion into the colon increased linearly with increase of plasma urea concentration. Dietary conditions and short-chain fatty acid concentrations in colonic contents had no significant effect on the permeability of the colonic epithelium for urea.
通过单次静脉注射[14C]尿素后，并依据绵羊和山羊的肾尿素排泄情况，得出进入体内尿素池的总尿素进入速率以及尿素水解速率（内源性尿素向整个胃肠道的转移）。根据暂时分离并灌注的结肠中尿素氮的出现情况估算内源性尿素向结肠的分泌量。进入结肠的尿素分泌速率相当低（0.10 - 0.31 mmol·h-1）。它仅占尿素进入速率的0.3 - 1.1%，或尿素水解速率的0.4 - 7%。进入结肠的尿素分泌量随血浆尿素浓度的升高呈线性增加。饮食条件以及结肠内容物中的短链脂肪酸浓度对结肠上皮对尿素的通透性无显著影响。
