No abstract

The concentrations of plasma cortisol were determined in two populations of female rainbow trout at the end of their reproductive cycles. In females ending vitellogenesis or having oocytes with germinal vesicles in peripheral positions, mean cortisol levels were low (about 8 to 10 ng/ml). Cortisol concentrations remained low during oocyte maturation (about 8 and 11 ng/ml). In contrast, a 3-fold cortisol increase was observed in females sampled in the postovulation period (about 26 and 31 ng/ml). These results are discussed in relation to other studies on endocrinological changes during the spawning season with emphasis on the possible role of cortisol in reproduction in female teleosts.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Distributed under a Creative Commons Attribution -ShareAlike| 4.0 International License Temporal aspects of macroscopic changes in rainbow trout (Salmo gairdneri) oocytes before ovulation and of ova fertility during the post-ovulation period; effect of treatment with 17α-hydroxy-20β-dihydroprogesterone C. Bry To cite this version:C. Bry. Temporal aspects of macroscopic changes in rainbow trout (Salmo gairdneri) oocytes before ovulation and of ova fertility during the post-ovulation period; effect of treatment with 17α-hydroxy-20β-dihydroprogesterone. Aquaculture, Elsevier, 1981, 24, pp.

Summary. Plasma