title: A comparison of the female reproductive cycles of autumn-spawning and winter-spawning strains of rainbow trout (Salmo gairdneri Richardson).
abstract: Annual changes in the plasma concentration of testosterone, 17 beta-estradiol, 17 alpha-hydroxy-20 beta-dihydroprogesterone, vitellogenin, and gonadotrophin were monitored by radioimmunoassay in females of autumn- and winter-spawning strains of rainbow trout. The annual profile of steroids and of vitellogenin, and the relationships between these parameters, were similar in the two strains, except that most changes occurred 2 months later in the winter-spawning strain than they did in the autumn-spawning strain. The times during which most fish ovulated in each strain were approximately 3 months apart, while gonadotrophin peaks, which were only detected about the time of ovulation, were 4 months apart. This phase shifting between the strains is discussed in terms of the environmental control of the reproductive cycle.
mesh_terms: D000818:Animals; D004958:Estradiol / Q000097:blood; D005260:Female; D006062:Gonadotropins / Q000097:blood; D009866:Oogenesis; D010060:Ovulation; D010507:Periodicity; D011374:Progesterone / Q000097:blood; D012098:Reproduction; D012487:Salmonidae / Q000502:physiology*; D012621:Seasons; D013045:Species Specificity; D013739:Testosterone / Q000097:blood; D014337:Trout / Q000502:physiology*; D014818:Vitellogenesis; D014819:Vitellogenins / Q000097:blood
chemical_list: D006062:Gonadotropins; D014819:Vitellogenins; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol