Circadian Changes in Serum Concentrations of Steroids in Japanese Char Salvelinus leucomaenis at the Stage of Final Maturation
| Autor: | Hideaki Yamada, Munehico Iwata, Takeshi Hakuba, Ri-Ichi Satoh, Yasufumi Fujimoto, Akira Kambegawa, Hiroaki Chiba, Keigo Takaji, Masashi Ogoh |
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| Rok vydání: | 2002 |
| Předmět: |
Male
medicine.medical_specialty Time Factors Hydrocortisone biology Trout Serum concentration biology.organism_classification Circadian Rhythm Endocrinology Internal medicine Darkness medicine Animals Female Testosterone Animal Science and Zoology Circadian rhythm Gonadal Steroid Hormones Dark phase Salvelinus leucomaenis Progesterone |
| Zdroj: | Zoological Science. 19:891-898 |
| ISSN: | 0289-0003 |
| Popis: | Circadian changes in serum concentrations of testosterone (T), 11-ketotestosterone (11KT), estradiol-17beta (E2), 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP), 17alpha-hydroxyprogesterone (OHP), cortisol (F) and progesterone (P) were investigated in the spermiated/ovulated Japanese char Salvelinus leucomaenis for over three days using newly developed time-resolved fluoroimmunoassays. Testosterone and DHP in both sex and 11KT in male showed significantly (P0.05) higher serum levels just before/after onset of darkness (15:00 or 18:00), and the levels during night and daytime were significantly (P0.05) lower than those of the peak levels. Serum F levels in both sex during dark phase were significantly (P0.05) higher than those levels during daytime. A surge of serum OHP concentrations in both sexes was observed at the time of twilight (03:00). The peak time of serum T, 11KT and DHP levels were approximately 6 hours prior to those of serum F and OHP levels. Serum E2 in female and P in both sex fluctuated intensely during sampling period, and did not show remarkable changes. These results strongly suggest the existence of circadian-like diel changes in serum T, DHP, F and OHP levels in both sex and 11KT in male, and no variations in serum E2 in female and P in both sex in spermiated/ovulated Japanese char under the stage of final maturation. Furthermore, relationship between circadian rhythms of steroid hormones and spawning behaviors are discussed in the present study. |
| Databáze: | OpenAIRE |
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