Genetic-physiological studies of osmoregulation in the sole Paralichthys orbignyanus
The objective of the present work was to quantify the activity of the enzyme Na +, K + - branchial ATPase and the concentration of ions Na +, K + and Cl- in plasma; identify possible histological changes in the gills, kidneys and esophagus and verify the action of growth hormone (GH) after transferring the sole Paralichthys orbignyanus to salt water. Isolation, sequencing and expression of the GH cDNA and part of the hormone receptor (GHR) cDNA sequence were performed using Reverse Transcription - Polymerase Chain Reaction (RT-PCR). The presence of the GHR cDNA in the gills was identified, and the GH showed a higher expression in specimens acclimated to salinity 30. There was no histological difference between individuals acclimated to different salinities, nor in Na +, K + -ATPase activity.The K + and Na + ions analyzed showed a significant increase 6 hours after the salt shock, and the Cl- after 3 hours. These results seem to indicate that GH plays an important role in the osmoregulation of P. orbignyanus and possibly the marine origin of the sole explains its great tolerance to variations in salinity above its isosmotic point, as it has well-developed mechanisms capable of osmoregulation without major morphological changes. and enzymatic.for having well-developed mechanisms capable of osmoregulation without major morphological and enzymatic changes.