Stimulation of water and sodium secretion and inhibition of glucose absorption from the rat jejunum during intraarterial infusions of prostglandins.

Abstract

SUMMARY The effect of prostaglandins, isoprenaline and dibutyryl cyclic adenosine monophosphate (dibut cAMP) on the net transfer of water and Na+ and glucose absorption have been studied in the anaesthetized rat.The lumen of the jejunum was recirculated with a solution of normal saline containing D(+) glucose and phenosulphonphthalein. The superior mesenteric artery was perfused extracorporeally and drugs were infused into the arterial blood.Prostaglandin El (PGE1) at infusion rates of 2-5 x 10-9 and 10-8 mol/min induced a net secretion of water and Na+ which was significantly different from the infused control mean. Both water and Na+ secretion were dose-related. PGE, induced slight but significant inhibition of glucose absorption at 10-8 mol/min. This could either be a direct effect or secondary to solvent drag. PGE2 (2.5 x 10-9 mol/min) and PGF2a (8 x 10-9 mol/min) induced water and Na+ secretion, and inhibited glucose absorption but not significantly.Isoprenaline (10-9 mol/min) and dibut cAMP (8 x 10-9 mol/min) did not alter water, Na+ or glucose absorption.Prostaglandins affect gastrointestinal motility by a direct action on smooth muscle, alter intestinal blood flow (Waller, 1973;Nakano, 1973) and promote the secretion of fluid and electrolytes into the lumen (Greenough, Pierce, Al-Awqati, and Carpenter, 1969;Matuchansky and Bernier, 1971). They are present within the gut wall of animals and man (Waller, 1973) and are released by vagal stimulation in the rat small intestine (Radmanovic, 1968). The effect of prostaglandin-induced secretion is similar to that produced by cholera exterotoxin (CE) and both may act on a common secretory process (Pierce, Carpenter, Elliot, and Greenough, 1971). Glucose has been shown to stimulate the mucosal to-serosal flux of water, Na+ and Cl-during prostaglandin and CE-induced secretion (Al-Awqati, Cameron, Field, and Greenough, 1970a;Al-Awqati and Greenough, 1972) but there is little available information on the effect of prostaglandins on the active absorption of glucose itself. Preliminary 'Present address:

Influence of Extra‐intestinal Inflammation on the in Vitro Absorption of 14c‐glucose and the Effects of Antiinflammatory Drugs in the Jejunum of Rats

“…However, prostaglandins have a short half life (Salmon, 1980) and are easily destroyed by lung tissues (Ferreira & Vane, 1967). In view of this and the fact that high concentrations of prostaglandins only cause a small decrease in glucose absorption from the rat jejunum (Coupar & McColl, 1975), it is unlikely that prostaglandins have a significant influence upon the intestinal absorption of glucose during peripheral inflammation. Our present observation on the decrease in absorption of ''C-glucose in rat jejunum after formalin injection tends to suggest the possibility that a non-PG type of mediator may be involved in such a phenomenon or it may be due to diffusion of formalin into the systemic circulation and this would have affected the absorption.…”

Stimulation of Sodium and Water Secretion Without Inhibition of Glucose Absorption in the Rat Jejunum by Vasoactive Intestinal Peptide (Vip)

“…Apart from this difference in potency there is perhaps a more important difference between the effects of VIP and PGE, on the small intestinal mucosa. Whereas PGE, has previously been shown to cause a small but significant inhibition of glucose absorption (Coupar & McColl, 1975), VIP does not alter glucose absorption even though it caused a greater secretion than PGE,. This distinction may be relevant to the mode of action of cholera enterotoxin since it has been proposed that a peptide such as VIP (Barbezat & Grossman, 1971) or prostaglandins (Bennett, 1971) may be released from the gut by the toxin.…”

“…The method for measuring intestinal absorption of glucose and net secretion of Na' and water during vascular perfusion of the small intestine has been previously described in detail (Coupar & McColl, 1975). Blood coagulation was inhibited by the i.v.…”

Evidence implicating a prostaglandin as the mediator of intestinal fluid secretion induced by pithing: inhibition by indomethacin, morphine and pentobarbitone

“…An E-type prostaglandin was' a candidate for mediating the fluid secretion since PGE compounds cause doserelated inhibition of absorption, followed by stimulation of water secretion (Greenough et a1 1969;Matuchansky & Bernier 1971;Coupar & McColl 1975). The main products of cyclo-oxygenase in extracts of rat jejunum were reported to be PGE2, PGF2, and PGD2 (Knapp et al 1978).…”