Administration of 17 alpha-hydroxyprogesterone into mature male Japanese eel reduces sperm motility by decreasing potassium ion concentrations in the seminal plasma

作者：Miura Akira; Nomura Kazuharu; Imaizumi Hitoshi; Jinbo Tadao; Masuda Yoshitsugu; Tanaka Hideki; Ohta Hiromi^*

来源：Aquaculture, 2013, 414: 217-223.

DOI：10.1016/j.aquaculture.2013.08.011

• Japanese eel
• 17 alpha-hydroxyprogesterone
• sperm motility
• potassium ion
• pH
• seminal plasma

Our objective was to evaluate the effects of hormonal treatments on the milt quality during the induction of spontaneous spawning in male eels. We measured the changes in milt characteristics (sperm motility, milt pH, seminal plasma ionic concentration) during the course of hormonal treatments intended to induce spontaneous spawning, and before and after spawning. Male eels received weekly injections of hCG (1 IU/g BW/wk) to maintain spermiation. To induce spontaneous spawning, males received another priming injection of hCG (1 IU/g BW) two days before spawning, followed 24 h later by an injection of 17 alpha-hydroxyprogesterone (OHP: 1 mu g/g BW). Three males, treated as described above, and one female, that had received hormonal injections to induce vitellogenesis and final maturation, were transferred to a tank to spawn. In Experiment 1, we measured the characteristics of milt (1) before administering the priming dose (1-2 days after the weekly injection of hCG), (2) before injection with OHP, (3) after spawning (24 h after the OHP injection), and (4) before weekly injections with hCG (4-5 days after OHP injection). To evaluate the effects of hormonal treatment on the characteristics of milt we administered the same treatments but did not allow spawning (Experiment 2). In both experiments, the percent motility remained high prior to OHP injection, decreased significantly 24 h after OHP injection, then recovered by the beginning of weekly hCG injection. The changes in potassium ion concentration were similar to those in sperm motility (%) but there was no change in pH and sodium ion concentrations. When the results were analyzed by individual in Experiment 1 (n = 34), the relationship between sperm motility (%) and milt pH showed significant correlations without 24 h after the OHP injection. The relationship between sperm motility (%) and potassium ion concentration showed a highly significant correlation 24 h after the OHP injection. Thus, both pH and potassium ion concentration regulate motility in Japanese eel spermatozoa during hormonal treatment. Furthermore, administration of OHP into spermiating males reduced motility by decreasing the potassium ion concentration in the seminal plasma.

• 出版日期2013-11-15