Seasonal changes in gene expression of corticoid receptors in anadromous and non‐anadromous strains of rainbow trout Oncorhynchus mykiss. Issue 4 (October 2014)

• Record Type: Journal Article
• Authors: Yada, T.; Miyamoto, K.; Miura, G.; Munakata, A.
• Is Part Of: Journal of fish biology. Volume 85:Issue 4(2014)
• Page Start: 1263
• Page End: 1278
• Publication Date: 2014-10
• Subjects: Fishes -- Periodicals; Fishes -- Great Britain -- Periodicals; 597
• DOI: 10.1111/jfb.12521
• Languages: English
• ISSNs: 0022-1112

Abstract

<abstract abstract-type="main" id="jfb12521-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p id="jfb12521-para-0001">To clarify the regulation of expression of corticoid receptor (CR) genes during period of parr–smolt transformation of salmonids, seasonal changes in mRNA levels of glucocorticoid receptor (GR)‐<italic>1</italic>, GR‐2 and mineralocorticoid receptor (MR) were examined in gill, leucocytes, spleen and brain of anadromous and non‐anadromous forms of <italic>Oncorhynchus mykiss</italic>. Increases in gill Na<sup>+</sup>, K<sup>+</sup> ATPase activity, plasma thyroxine levels and hypo‐osmoregulatory ability assessed by 24 h seawater challenge test represented characteristics of smoltification in anadromous <italic>O. mykiss</italic> from May to June, whereas there was no apparent increase in the values of non‐anadromous <italic>O. mykiss</italic>. Plasma cortisol levels of anadromous <italic>O. mykiss</italic> were higher than levels of non‐anadromous <italic>O. mykiss</italic> from April to June. In gill of non‐anadromous <italic>O. mykiss</italic>, there were significant increases in mRNA levels of three types of CR in spring. Although there were significant seasonal variations of CR mRNA levels in gill of anadromous <italic>O. mykiss</italic>, they appear to be less clear than those variations in non‐anadromous <italic>O. mykiss</italic>. In anadromous <italic>O. mykiss</italic>, significant elevations in mRNA levels of the three types of CR were observed especially in the spleen. In both preoptic area and basal hypothalamus of the brain, there were tendencies to increase in CR mRNA levels from spring to summer in both anadromous and non‐anadromous <italic>O. mykiss</italic>. These results showed difference in regulation of CR gene expression between the two forms of <italic>O. mykiss</italic> for osmoregulatory, immune and central nervous systems.</p> </abstract>