Effects of various secretagogues and human carcinoid serum on lymph flow in the cat ileum.

Previous studies from our laboratory indicate that the lymph flow response of the cat ileum to net volume secretion is dependent upon the mechanism involved in the secretory process, i.e, active secretion (cholera toxin) decreases lymph flow while passive fluid secretion (increased portal pressure, plasma dilution) is associated with a rise in lymph flow. In the present study, we examined the effects of ricinoleic acid, vasoactive intestinal polypeptide, theophylline, histamine, and human carcinoid serum on lymph flow in autoperfused segments of cat ileum. Local intraarterial infusion of theophylline, vasoactive intestinal polypeptide, or human carcinoid serum caused lymph flow to decrease. However, intraluminal placement of ricinoleic acid or intraarterial infusion of histamine produced significant increases in lymph flow. The results indicate that the fluid secretion associated with vasoactive intestinal polypeptide, theophylline, and carcinoid serum are consistent with an active process while ricinoleic acid and histamine secretions are associated with a passive component.