Annual sex steroid and other physiological profiles of Pacific lampreys (Entosphenus tridentatus)

Comparative Biochemistry and Physiology, Part A: Molecular & Integrative Physiology
By: , and 

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Abstract

We documented changes in plasma levels of estradiol 17-β (E2), progesterone (P), 15α-hydroxytestosterone (15α-T), thyroxine (T4), triiodothyronine (T3), protein, triglycerides (TGs), and glucose in adult Pacific lampreys (Entosphenus tridentatus) held in the laboratory in two different years. Levels of E2 in both sexes ranged from 0.5 to 2 ng/mL from September to March, peaked in late April (2–4 ng/mL), and decreased in May, with levels higher in males than in females. Levels of P were low from September through April, but then increased substantially during May (2–4 ng/mL), with levels again highest in males. Levels of 15α-T in males were around 0.75 ng/mL through the winter before exceeding 1 ng/mL in April and decreasing thereafter, whereas females showed a gradual increase from 0.25 ng/mL in November to 0.5 ng/mL in April before decreasing. Thyroxine concentrations differed between fish in each year, with most having levels ranging from 0.75 to 2.5 ng/mL in the fall and winter, and only fish in 2003 showing distinct peaks (3–4 ng/mL) in early April or May. Plasma T3 was undetectable from November through mid-March before surging dramatically in April (ca. 150 ng/mL) and decreasing thereafter. Levels of protein, TGs, and glucose decreased or were stable during the fall and winter with TGs and glucose surging in late April to early May for some fish. Our study is the first to document long-term physiological changes in Pacific lampreys during overwintering and sexual maturation and increases our understanding of the life history of this unique fish.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Annual sex steroid and other physiological profiles of Pacific lampreys (Entosphenus tridentatus)
Series title Comparative Biochemistry and Physiology, Part A: Molecular & Integrative Physiology
DOI 10.1016/j.cbpa.2009.09.019
Volume 155
Issue 1
Year Published 2010
Language English
Publisher Elsevier
Contributing office(s) Western Fisheries Research Center
Description 8 p.
First page 56
Last page 63