TY - JOUR
T1 - 11-Deoxycorticosterone is a potent agonist of the rainbow trout (Oncorhynchus mykiss) mineralocorticoid receptor
AU - Sturm, A.
AU - Bury, N.
AU - Dengreville, L.
AU - Fagart, J.
AU - Flouriot, G.
AU - Rafestin-Oblin, M. E.
AU - Prunet, P.
PY - 2005/1/1
Y1 - 2005/1/1
N2 - The teleost fish are thought to lack the mineralocorticoid hormone aldosterone but possess mineralocorticoid receptor (MR) homologs. Here we describe the characterization of two rainbow trout (Oncorhynchus mykiss) MRs, called rtMRa and rtMRb. The open reading frame of rtMRa cDNA encoded a protein of 1041 amino acids. The rtMRb predicted protein sequence is similar, differing in only 10 amino acids in the nonconserved A/B domain and lacking a three-amino acid insertion between the two zinc fingers of the C domain. Expression of rtMR mRNA (sum of both forms), measured in juvenile trout by real-time RT-PCR, shows that the transcripts are ubiquitous. Expression was significantly higher in brain than the other tissues studied (eye, trunk kidney, head kidney, gut, gills, liver, spleen, ovary, heart, white muscle, skin). Hormonal stimulation of receptor transactivation activity was studied in COS-7 cells transiently cotransfected with receptor cDNA and a mouse mammary tumor virus-luciferase reporter. The mineralocorticoids 11-deoxycorticosterone and aldosterone were more potent enhancers of rtMRa transcriptional activity (EC50 = 1.6 ± 0.5 × 10-10 and 1.1 ± 0.4 × 10 -10 M, respectively) than the glucocorticoids cortisol and 11-deoxycortisol (EC50 = 1.1 ± 0.3 × 10-9 and 3.7 ± 1.9 × 10-9 M, respectively). A similar response was observed in transactivation assays with rtMRb. These results are discussed in the view of reported circulating levels of corticosteroids in trout.
AB - The teleost fish are thought to lack the mineralocorticoid hormone aldosterone but possess mineralocorticoid receptor (MR) homologs. Here we describe the characterization of two rainbow trout (Oncorhynchus mykiss) MRs, called rtMRa and rtMRb. The open reading frame of rtMRa cDNA encoded a protein of 1041 amino acids. The rtMRb predicted protein sequence is similar, differing in only 10 amino acids in the nonconserved A/B domain and lacking a three-amino acid insertion between the two zinc fingers of the C domain. Expression of rtMR mRNA (sum of both forms), measured in juvenile trout by real-time RT-PCR, shows that the transcripts are ubiquitous. Expression was significantly higher in brain than the other tissues studied (eye, trunk kidney, head kidney, gut, gills, liver, spleen, ovary, heart, white muscle, skin). Hormonal stimulation of receptor transactivation activity was studied in COS-7 cells transiently cotransfected with receptor cDNA and a mouse mammary tumor virus-luciferase reporter. The mineralocorticoids 11-deoxycorticosterone and aldosterone were more potent enhancers of rtMRa transcriptional activity (EC50 = 1.6 ± 0.5 × 10-10 and 1.1 ± 0.4 × 10 -10 M, respectively) than the glucocorticoids cortisol and 11-deoxycortisol (EC50 = 1.1 ± 0.3 × 10-9 and 3.7 ± 1.9 × 10-9 M, respectively). A similar response was observed in transactivation assays with rtMRb. These results are discussed in the view of reported circulating levels of corticosteroids in trout.
U2 - 10.1210/en.2004-0128
DO - 10.1210/en.2004-0128
M3 - Article
C2 - 15486226
AN - SCOPUS:11144238598
SN - 0013-7227
VL - 146
SP - 47
EP - 55
JO - Endocrinology
JF - Endocrinology
IS - 1
ER -