Influence of plasma lipid changes in response to 17 beta-oestradiol stimulation on plasma growth hormone, somatostatin, and thyroid hormone levels in immature rainbow trout

Citation

Mercure F, Holloway AC, Tocher DR, Sheridan MA, Van der Kraak G & Leatherland JF (2001) Influence of plasma lipid changes in response to 17 beta-oestradiol stimulation on plasma growth hormone, somatostatin, and thyroid hormone levels in immature rainbow trout. Journal of Fish Biology, 59 (3), pp. 605-615. https://doi.org/10.1111/j.1095-8649.2001.tb02365.x

Abstract
Plasma total lipids were significantly higher in 17β-oestradiol(E2)-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 E2 treatment. Plasma growth hormone GH levels were increased, and plasma somatostatin-14 (SRIF) levels decreased in E2-treated fish, responses which could be secondary to elevated plasma lipid (VtG) content, although a direct E2 action on somatotroph function is possible. Plasma T4 concentrations were not affected by E2 treatment, but plasma T3 concentrations were significantly lower than in controls 1 week after implantation when plasma E2 concentrations were the highest; this is in support of the hypothesis that E2 has a suppressive action on T3 production.

Keywords
neutral lipid; oestrogen; phospholipid; polar lipid; reproduction; vitellogenin

Journal
Journal of Fish Biology: Volume 59, Issue 3