Role of second messengers in the release of motilin from isolated canine intestinal cells.
We examined the intracellular mechanisms for the release of motilin in a preparation of mucosal cells obtained from dog duodenum. Enzymatically dispersed cells were separated by counterflow elutriation to enrich motilin content. Postreceptor activation process was studied by comparing the release of motilin obtained with exogenous analogues or stimulants of the various intracellular signal pathways. Dibutyryl cyclic adenosine monosphate (10(-3) M) and forskolin (10(-5) M) induced a moderate response in motilin secretion. Phorbol ester beta-phorphol-12-myristate-13-acetate and phospholipase C were potent stimulants of motilin release. Raising intracellular calcium concentration by calcium ionophore A23187 or increasing calcium content in the incubation milieu failed to modify the secretion of motilin. Analogues of 8-bromoguanosine-3'5' cyclic monosphosphate were ineffective. Therefore, the motilin cell was very sensitive to protein kinase C activators and appeared moderately responsive to a stimulation of the adenylate cyclase pathway.
Poitras
P
P
André-Viallet Clinical Research Center, Hospital Saint-Luc (Université de Montréal), Quebec, Canada.
Coimbra
C
C
Trudel
L
L
D000818:Animals; D002469:Cell Separation; D004285:Dogs; D004386:Duodenum / Q000166:cytology / Q000378:metabolism*; D066298:In Vitro Techniques; D009037:Motilin / Q000378:metabolism*; D015290:Second Messenger Systems / Q000502:physiology*
D009037:Motilin