TLQP-21, a VGF-derived peptide, stimulates exocrine pancreatic secretion in the rat

Department of Physiology and Pharmacology V. Erspamer, Sapienza University of Rome, Rome, Italy.
Peptides (Impact Factor: 2.62). 04/2012; 36(1):133-6. DOI: 10.1016/j.peptides.2012.03.035
Source: PubMed


The aims of this paper were to study: (1) the effects of TLQP-21 (non-acronic name), the C-terminal region of the VGF (non-acronic name), polypeptide (from residue 557 to 576 of VGF), on in vitro amylase release from rat isolated pancreatic lobules and acinar cells; (2) the mechanism through which TLQP-21 regulates exocrine pancreatic secretion, by using the muscarinic receptor antagonist atropine (10(-6)M) and the cyclo-oxygenase inhibitor, indomethacin (10(-6)M). On pancreatic lobules of rats, concentrations of TLQP-21 from 10(-7) to 10(-5)M significantly (p<0.05) induced a 2-3-fold increase of baseline pancreatic amylase release, measured at the end of 60 min incubation period. Co-incubation with atropine 10(-6)M did not antagonise the enzyme outflow induced by the peptide. On the contrary, co-incubation of TLQP-21 (10(-7) and 10(-6)M) with indomethacin, at concentration of 10(-6)M, which alone did not modify enzyme secretion, completely suppressed the increase of amylase evoked by TLQP-21 on pancreatic lobules. On rat pancreatic acinar cells, TLQP-21, at all the concentrations tested, was unable to affect exocrine pancreatic secretion, indicating an indirect mechanism of action on acinar cells. These results put in evidence, for the first time, that TLQP-21, a VGF-derived peptide, modulates exocrine pancreatic secretion in rats through a stimulatory mechanism involving prostaglandin release. In conclusion, TLQP-21 could be included among the neurohumoral signals regulating pancreatic exocrine secretion, and increases the knowledge concerning the systems controlling this function.

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    • "One of its best characterized peptides is TLQP-21 (amino acid residues 556 to 576) [6]. At present, several biological functions of this peptide have been identified, including negative effects on body weight via increased energy expenditure and control of gut functioning [6]–[8], a gastroprotective role against ethanol injury via increased levels of constitutive nitric oxide (NO) and prostaglandin E2 (PGE2) [9], and possible indirect regulation of pancreatic exocrine secretion [10]. "
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