Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Plasma concentrations of ovarian steroids in the freshwater European silver eel (Anguilla anguilla L.): effects of hypophysectomy and transfer to sea water

Plasma concentrations of ovarian steroids in the freshwater European silver eel (Anguilla... ABSTRACTIntact and hypophysectomized freshwater (FW) silver eels were transferred to tanks of FW or artificial sea water (SW; salinity = 0·60 osmol/l) which were simultaneously renewed twice a week. Fish were killed 2 months after transfer and plasma was assayed for ovarian steroids.In all fish, 5α-androstane-3β,17β-diol was present, while 5α-dihydrotestosterone and 5α-androstane-3α,17β-diol were undetectable.In intact FW eels, plasma levels of testosterone, 5α-androstane-3β,17β-diol and oestradiol-17β were approximately 0·15 nmol/l. In intact SW eels, no change in plasma levels of testosterone and 5α-androstane-3β,17β-diol was found, whereas the concentration of oestradiol-17β was increased significantly (P<0·01), indicating stimulation of aromatase activity.In hypophysectomized compared with intact FW fish, plasma levels of testosterone and 5α-androstane-3β,17β-diol were decreased (P<0·05) and there was a slight but significant (P<0·01) augmentation of the plasma concentration of oestradiol-17β which may have involved the removal of pituitary-dependent inhibition of aromatase activity, possibly by 5α-reduced compounds.In hypophysectomized compared with intact SW fish, plasma levels of testosterone, 5α-androstane-3β,17β-diol and oestradiol-17β were decreased (P<0·05); in the case of oestradiol-17β, this may have reflected the diminished ovarian synthesis of testosterone, its precursor. The plasma level of oestradiol-17β was, however, higher in SW than in FW fish, even in hypophysectomized eels. This suggests that extra-pituitary mechanisms mediate, at least partly, the effects of transfer to SW on aromatase activity.J. Endocr. (1987) 114, 289–294 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Endocrinology Bioscientifica

Plasma concentrations of ovarian steroids in the freshwater European silver eel (Anguilla anguilla L.): effects of hypophysectomy and transfer to sea water

Download PDF
6 pages

Loading next page...
 
/lp/bioscientifica/plasma-concentrations-of-ovarian-steroids-in-the-freshwater-european-RFval36uqF

References

References for this paper are not available at this time. We will be adding them shortly, thank you for your patience.

Publisher
Bioscientifica
Copyright
Copyright © 1987 The Authors. All Rights Reserved.
ISSN
0022-0795
eISSN
1479-6805
DOI
10.1677/joe.0.1140289
Publisher site
See Article on Publisher Site

Abstract

ABSTRACTIntact and hypophysectomized freshwater (FW) silver eels were transferred to tanks of FW or artificial sea water (SW; salinity = 0·60 osmol/l) which were simultaneously renewed twice a week. Fish were killed 2 months after transfer and plasma was assayed for ovarian steroids.In all fish, 5α-androstane-3β,17β-diol was present, while 5α-dihydrotestosterone and 5α-androstane-3α,17β-diol were undetectable.In intact FW eels, plasma levels of testosterone, 5α-androstane-3β,17β-diol and oestradiol-17β were approximately 0·15 nmol/l. In intact SW eels, no change in plasma levels of testosterone and 5α-androstane-3β,17β-diol was found, whereas the concentration of oestradiol-17β was increased significantly (P<0·01), indicating stimulation of aromatase activity.In hypophysectomized compared with intact FW fish, plasma levels of testosterone and 5α-androstane-3β,17β-diol were decreased (P<0·05) and there was a slight but significant (P<0·01) augmentation of the plasma concentration of oestradiol-17β which may have involved the removal of pituitary-dependent inhibition of aromatase activity, possibly by 5α-reduced compounds.In hypophysectomized compared with intact SW fish, plasma levels of testosterone, 5α-androstane-3β,17β-diol and oestradiol-17β were decreased (P<0·05); in the case of oestradiol-17β, this may have reflected the diminished ovarian synthesis of testosterone, its precursor. The plasma level of oestradiol-17β was, however, higher in SW than in FW fish, even in hypophysectomized eels. This suggests that extra-pituitary mechanisms mediate, at least partly, the effects of transfer to SW on aromatase activity.J. Endocr. (1987) 114, 289–294

Journal

Journal of Endocrinology – Bioscientifica

Published: Aug 1, 1987

There are no references for this article.