Interaction between pepsin and acid secretion during fundic perfusion in cat and rabbit.

1. The effect of perfusion at pH 5.5 of a Heidenhain pouch on acid and pepsin secretion was studied in cats and rabbits. 2. In basal conditions, acid secretion was not modified by the perfusion while pepsin secretion was increased in both species. 3. After a meal, the perfusion did not modify the stimulation of acid secretion in cats nor the absence of secretions in rabbit. Stimulation of pepsin secretion was the same with or without perfusion in both species. 4. In rabbit, in contrast to cat, pepsin and acid secretions were independent during the meal-induced phase of gastric secretion.

Variation of gastric lipase secretion in the Heidenhain pouch of the cat.

In the cat, gastric lipase secretion was equally but weakly stimulated by pentagastrin, a major stimulant of acid secretion, and by carbamylcholine, a major stimulant of pepsin secretion. Lipase was also stimulated by fresh liver, which induces a large blood gastrin release and not by canned food, which is a poor gastrin releaser. Lipase output always preceded that of acid an pepsin. Lipase was not correlated with acid and pepsin secretion while acid and pepsin were well correlated during all stimulations but not in basal state. Lipase is co-localized with pepsin in the chief cells but is also present in pepsin-free cells, the mucus surface cells of the fundus and the antrum. The distribution of lipase explains the lack of correlation between pepsin and lipase as already mentioned. However, our data show that lipase secretion is under the control of gastric stimulants and might play a role in the gastric initiation of pancreatic meal lipolysis.

Isolation and characterisation of porcine sorbin.

Sorbin has been isolated from extracts of porcine upper intestine, and the biological activity in absorbing water and electrolytes utilized to monitor the purification procedure. Pure sorbin was obtained in a yield of about 1 mg/Mg boiled intestine. The protein chain has 153 amino acid residues and the primary structure was determined by analyses of CNBr-cleaved fragments and four enzymatic digests. The protein has a free N-terminal Met and an amidated C-terminal Ala. No structural similarity was observed with other known proteins in data bases, but several segments have special properties and the C-terminal half is rich in Pro and Arg.

Effect of D ala2 metenkephalinamide on feline jejunal and ileal water and electrolyte transport.

The aim of this investigation was to compare the effect of an opioid, D ala2 metenkephalinamide (DAMA), on net jejunal and ileal water and electrolyte fluxes using the gut perfusion technique in the anesthetized cat. Intestinal transport was measured during intravenous infusion of serial doses of 2, 6, and 18 micrograms.kg-1.h-1 of DAMA in 6 cats. Each cat was its own control during an intravenous infusion of 150 mmol/l NaCl preceding the first dose of peptide and following the last dose of DAMA. Both jejunal and ileal segments were isolated by inflated balloons and were studied at the same time. Fifteen ml of an iso-osmolar test solution with hypo-osmolar ion contents and complementary mannitol were administered in the upstream tube and collected 1 h later in the downstream tube. In the jejunum, water secretion was dose-dependently reversed to an absorption from a control value of +0.5 +/- 0.4 to -0.83 +/- 0.5 ml.h-1.10 cm-1; in the ileum, water absorption was increased from -0.5 +/- 0.3 to -1.5 +/- 0.2 ml.h-1.10 cm-1. The net absorption of all electrolytes, ie sodium, chloride, bicarbonate, potassium and calcium also increased during peptide administration. However, a qualitative difference in the ion transport was observed between the jejunum and the ileum.