ZFIN ID: ZDB-PUB-120510-18
The effect of fasting and refeeding on mRNA expression of PepT1 and gastrointestinal hormones regulating digestion and food intake in zebrafish (Danio rerio)
Koven, W., and Schulte, P.
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.

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.