Intravenous administration of the food-derived opioid peptide gluten exorphin B5 stimulates prolactin secretion in rats.
Gluten Exorphin B5 (GE-B5) is a food-derived opioid peptide, identified in vitro in enzymatic digests of wheat gluten. It has been suggested that this peptide may play a regulatory role on pituitary secretion, since it stimulates prolactin (PRL) secretion when administered in the cerebral ventricles in rats. It is not known, however, if GE-B5 can exert this stimulatory action after peripheral administration. In order to clarify this aspect, we gave the following treatments to four groups of male rats: intravenous (i.v.) vehicle, GE-B5 3 mg/kg body weight i.v., naloxone intraperitoneally (i.p.) followed by vehicle i.v., naloxone i.p. followed by GE-B5 i.v. Blood samples for PRL were taken at intervals for 60 min after vehicle or GE-B5 administration. At the dose of 3 mg/kg body weight, GE-B5 induced a significant increase in PRL levels; naloxone completely abolished any effect of GE-B5 on PRL secretion. The present study indicates that GE-B5 stimulates PRL secretion after peripheral administration and that its action is mediated via classical opioid receptors; moreover, it identifies the minimum peptide dose which must reach the blood in order to exert its action on PRL secretion.
Fanciulli
Giuseppe
G
Dipartimento-Struttura Clinica Medica-Patologia Speciale Medica, Istituto di Patologia Medica, University of Sassari, Viale San Pietro 8, 07100 Sassari, Italy. gfanciu@uniss.it
Dettori
Alessandra
A
Fenude
Emma
E
Demontis
Maria Piera
MP
Alberico
Elisabetta
E
Delitala
Giuseppe
G
Anania
Vittorio
V
D000818:Animals; D005502:Food; D005983:Glutens / Q000008:administration & dosage* / Q000138:chemical synthesis; D007275:Injections, Intravenous; D008297:Male; D009842:Oligopeptides / Q000008:administration & dosage* / Q000138:chemical synthesis; D018847:Opioid Peptides / Q000008:administration & dosage* / Q000138:chemical synthesis; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D009842:Oligopeptides; D018847:Opioid Peptides; C095012:exorphin B5; D005983:Glutens; D011388:Prolactin