title: Pharmacokinetics of proline-rich tripeptides in the pig.
abstract: Tripeptides may possess bioactive properties. For instance, blood pressure lowering is attributed to the proline-rich tripeptides Ile-Pro-Pro (IPP), Leu-Pro-Pro (LPP), and Val-Pro-Pro (VPP). However, little is known about their absorption, distribution, and elimination characteristics. The aim of this study was to characterize the pharmacokinetic behavior of IPP, LPP, and VPP in a conscious pig model. Synthetic IPP, LPP, and VPP were administered intravenously or intragastrically (4.0 mg kg(-1) BW in saline) to 10 piglets (approximately 25 kg body weight) in the postabsorptive state. After intravenous dosing, the elimination half-life for IPP was significantly higher (P<0.001) than for LPP and VPP (2.5+/-0.1, 1.9+/-0.1, and 2.0+/-0.1 min, respectively). After intragastric dosing, however, the elimination half-lives were not significantly different between the peptides (9+/-1, 15+/-4, and 12+/-6 min, respectively). Maximum plasma concentrations were about 10 nmol l(-1) for the three tripeptides. The fraction dose absorbed was 0.077+/-0.010, 0.059+/-0.009, and 0.073+/-0.015%, for IPP, LPP, and VPP, respectively. Proline-rich tripeptides reach the blood circulation intact, with an absolute bioavailability of about 0.1% when administered via a saline solution. Because half-lives of absorption and elimination were maximally about 5 and 15 min, respectively, this suggests that under these conditions a bioactive effect of these tripeptides would be rather acute.
authors.affiliation: Unilever Food & Health Research Institute, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands. pieter-van-der.pijl@unilever.com
authors.forename: Pieter C
authors.initials: PC
authors.lastname: van der Pijl
authors.forename: Arie K
authors.initials: AK
authors.lastname: Kies
authors.forename: Gabriella A M
authors.initials: GA
authors.lastname: Ten Have
authors.forename: Guus S M J E
authors.initials: GS
authors.lastname: Duchateau
authors.forename: Nicolaas E P
authors.initials: NE
authors.lastname: Deutz
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000493:pharmacokinetics*; D005260:Female; D009842:Oligopeptides / Q000493:pharmacokinetics*; D013552:Swine
chemical_list: D000959:Antihypertensive Agents; D009842:Oligopeptides; C489032:isoleucyl-prolyl-proline; C535179:leucyl-prolyl-proline; C489031:valyl-prolyl-proline