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Influence of plasma lipid changes in response to 17β‐oestradiol stimulation on plasma growth hormone, somatostatin, and thyroid hormone levels in immature rainbow trout
Author(s) -
Mercure F.,
Holloway A. C.,
Tocher D. R.,
Sheridan M. A.,
Kraak G.,
Leatherland J.F.
Publication year - 2001
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2001.tb02365.x
Subject(s) - medicine , endocrinology , biology , somatostatin , vitellogenin , rainbow trout , hormone , stimulation , biochemistry , fish <actinopterygii> , fishery , gene
Plasma total lipids were significantly higher in 17β‐oestradiol(E 2 )‐treated immature rainbow trout Oncorhynchus mykiss at week 4 after implantation, due to increases in polar and neutral lipids. The lipid classes responding were phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, sterols and sterol esters, in a proportion that approximately reflected the increase in plasma vitellogenin (VtG) levels as measured by a non‐competitive enzyme‐linked immunosorbent assay (ELISA). Plasma non‐esterified fatty acids and triacylglycerol were not affected by E 2 treatment. Plasma growth hormone GH levels were increased, and plasma somatostatin‐14 (SRIF) levels decreased in E 2 ‐treated fish, responses which could be secondary to elevated plasma lipid (VtG) content, although a direct E 2 action on somatotroph function is possible. Plasma T 4 concentrations were not affected by E 2 treatment, but plasma T 3 concentrations were significantly lower than in controls 1 week after implantation when plasma E 2 concentrations were the highest; this is in support of the hypothesis that E 2 has a suppressive action on T 3 production.