Gastric uptake of recombinant growth hormone in rainbow trout

Abstract

The aim of the present study was to investigate gastrointestinal uptake of recombinant growth hormone in rainbow trout. Recombinant human GH was used in this study to avoid cross reactivity with the endogenous trout GH molecule. Using both in vitro and in vivo approach, the results demonstrate that stomach is the main site of uptake for orally administered intact recombinant human growth hormone (hGH) in rainbow trout. The presence of hGH was verified by western blot analysis in the stomach tissue as well as in the serum after 30 minutes of intubation. No traces of the hGH could be detected after 90 minutes of administration, indicating rapid clearance of the hormone in rainbow trout. Furthermore, no immunoreactive hGH was detected in other tissues including mid-gut, muscle and liver at the time points tested. The findings provide novel information on the gastric uptake of hGH in rainbow trout, and would be of relevance to the application of GH in aquaculture.