[Effect of C-terminal derivatives of sorbin on duodenal ion transports in rats].
OBJECTIVE
Synthetic derivatives of sorbin have been shown to inhibit VIP stimulated fluxes in the ileum in decreasing plasma-to-mucosa Na and Cl effluxes. The effect of this group of new peptides, without homology with any known peptides, was determined in rat duodenum where ion transport mechanisms differ. The improved technique of ligated loops in situ, was used, permitting the simultaneous measurement of net fluxes, influxes and effluxes for Na and Cl, in an integrated in vivo model. To determine the minimal active fragment of sorbin, synthetic C5, C7 and C20 peptides were tested and compared with known anti-secretor drugs such as loperamide, neuropeptide Y, somatostatine and metenkephalinamide.


RESULTS
C7-sorbin was the minimal peptide able to decrease duodenal VIP-stimulated fluxes of water, Na and bicarbonate. It intervenes in increasing Na influx and more slightly Cl influx, which have been decreased by VIP. It does not modify much Na and Cl effluxes stimulated by VIP. Sorbin effect is in contrast with those of known antidiarrheic agents like somatostatine, loperamide, NPY and metenkephalinamide which chiefly decrease Cl efflux.


CONCLUSIONS
Sorbin acts like an activator of absorption in the duodenum, in contrast to the other peptides or drugs and to its own anti-secretor effect in the ileum.
Grishina
O
O
INSERM Unité 45, EPHE, Hôpital Edouard-Herriot, Lyon.
Charpin
G
G
Marquet
F
F
Pansu
D
D
Descroix-Vagne
M
M
D000818:Animals; D000930:Antidiarrheals / Q000493:pharmacokinetics; D018118:Chloride Channels / Q000378:metabolism*; D003864:Depression, Chemical; D004386:Duodenum / Q000187:drug effects*; D017136:Ion Transport / Q000187:drug effects*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015222:Sodium Channels / Q000378:metabolism*; D013013:Sorbose / Q000031:analogs & derivatives / Q000493:pharmacokinetics*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism; D014882:Water-Electrolyte Balance / Q000187:drug effects
D000930:Antidiarrheals; D018118:Chloride Channels; D015222:Sodium Channels; D014660:Vasoactive Intestinal Peptide; D013013:Sorbose
Effet des dérivés C-terminaux de la sorbine sur les flux ioniques duodénaux chez le rat.