The aim of the present study was to analyze the effect of the specific cholecystokinin (CCK) receptor antagonist loxiglumide on hepatic and pancreatic processing of CCK-8 and the CCK analogue cerulein. Rat liver perfusion was performed in a non-recirculating system. CCK concentrations were measured by radioimmunoassay in perfusates from the inflow cannula (portal vein) and the outflow cannula (hepatic vein). In rat pancreatic acini, the effect of loxiglumide on internalization and surface-binding of radiolabelled CCK-8 was determined. Cerulein (20 nM, 2 nM) was extracted in a single pass through the liver by 29.7 and 25.4%, respectively. The hepatic uptake of CCK-8 (50 pM, 2 nM) was more than 90 and 89.9%, respectively. Loxiglumide drastically inhibited hepatic extraction of both peptides and reduced internalization of ¹²⁵I-CCK-8 in pancreatic acini dose dependently by 39–93%. These results demonstrate that the potent CCK receptor antagonist loxiglumide significantly decreased CCK uptake by the liver and pancreas.

No abstract

Nitrogen balances were determined for six young men fed three amino acid patterns : the F A 0 reference pattern, a modification of the F A 0 pattern in which methionine was decreased and phenylalanine increased isonitrogenously, and the wheat pattern. Total N intake was approximately 10 g. The lowest intakes of the F A 0 reference pattern amino acids found to be adequate for the support of N equilibrium or positive N balance contained 320 mg tryptophan in the case of two subjects, 280 mg tryptophan for three subjects, and 240 n~g tryptophan for one subject. Comparison of group mean N retentions for the F A 0 and the modified F A 0 patterns indicated that the two patterns were of equal value. When the F A 0 reference and wheat patterns were fed to provide comparable amounts of lysine, the limiting amino acid of wheat protein, group mean N retentions were 0.42 and 0.41 g, respectively. When the same two patterns were fed to provide an equivalent amount of essential amino acid N and the chief source of amino acids was intact wheat protein, group mean N retentions were 0.62 g for the F A 0 reference pattern, and 0.41 g for the wheat pattern; statistically, this difference is not significant. From 0.63 to 0.84 g essential amino acid N provided as F A 0 reference pattern was adequate to maintain N equilibrii~rn or a slight positive balance.