PUBLICATION

The effect of fasting and refeeding on mRNA expression of PepT1 and gastrointestinal hormones regulating digestion and food intake in zebrafish (Danio rerio)

Authors
Koven, W., and Schulte, P.
ID
ZDB-PUB-120510-18
Date
2012
Source
Fish physiology and biochemistry   38(6): 1565-1575 (Journal)
Registered Authors
Keywords
PepT 1, zebrafish, compensatory growth, protein absorption, CCK, ghrelin, GRP
MeSH Terms
  • Animals
  • Cholecystokinin/genetics
  • Cholecystokinin/metabolism
  • Digestion/physiology*
  • Eating/physiology*
  • Food Deprivation/physiology*
  • Gastrin-Releasing Peptide/genetics
  • Gastrin-Releasing Peptide/metabolism
  • Ghrelin/genetics
  • Ghrelin/metabolism
  • RNA, Messenger/genetics
  • RNA, Messenger/metabolism*
  • Real-Time Polymerase Chain Reaction
  • Symporters/genetics
  • Symporters/metabolism*
  • Zebrafish/metabolism*
PubMed
22565667 Full text @ Fish Physiol. Biochem.
Abstract

In vertebrates, a significant part of ingested protein is absorbed as di- and tripeptides through a brush border membrane proton/oligopeptide transporter protein called PepT1. The aim of the present study was to determine the effect of short-term food deprivation and refeeding in adult zebrafish (Danio rerio) on gastrointestinal mRNA expression of PepT1 as well as on the satiety hormones cholecystokinin (CCK), gastrin-releasing peptide (GRP) and ghrelin (GHR) in order to elucidate a potential mechanism driving compensatory growth. Sixty adult zebrafish were stocked in a 40-L aquarium and fed daily a commercial flake diet to satiation for 10 days where the digestive tracts (DT) of sampled fish (n = 5) were dissected out. Samplings were repeated following 1, 2 and 5 days of food deprivation and after 1, 2 and 5 days of refeeding. The RNA was extracted from all sampled DTs and analyzed by quantitative real-time PCR for the mRNA expression of PepT1, rRNA 18S, CCK, GRP and GHR. PepT1 mRNA expression increased with successive refeedings reaching a level approximately 8 times higher than pre-fast levels. CCK, GRP and GHR mRNA levels also decreased during fasting, but increased only to pre-fasting levels with refeeding. Overall, the results suggest that PepT1 may be a contributing mechanism to compensatory growth that could influence CCK secretion and GRP and GHR activity.

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