Ammonia-nitrogen turnover in the rabbit caecum and exchange with plasma urea-N

Abstract

1. Continuous infusion and single-shot administration of 15 NH 4 Cl into the caecum of the conscious rabbit was used to measure caecal ammonia flux. 2. Continuous infusion of 15 NH 4 Cl and sampling from both the caecal ammonia and blood urea pools indicated that 0.27 of plasma urea-nitrogen was derived from caecal ammonia-N. 3. Values from intravenous [ 15 N]urea and intracaecal 15 NH 4 Cl infusions were used to produce two models of the movement of N between these two metabolic pools. 4. Further analysis of the results suggested an alternative model involving a third pool associated with the caecal mucosa and values for this model are also presented.