Louis, MO) or 11-ketoandrostenedione (11KA, Sigma) (androgens implanted into castrated fish only) or with empty capsules sealed with silicone glue, as well as with a passive integrated transponder tag (Destron, Boulder, CO) for individual identification (both experiments). 11KA is known to be converted extragonadally into 11-ketotestos-terone (11KT), and implantation of 11KA capsules to castrated salmon raises plasma 11KT levels. Plasma steroid levels were not measured, since the plasma volumes were sufficient for measuring FSH and LH only. However, in another study, similar capsules containing T and 11KA implanted into castrated salmon parr weighing ~50 g gave plasma levels of —20 ng/ml T and 11KT, respectively, values that are within the upper part of the natural range for mature salmon parr. In the present study, the fish grew considerably over the experimental period. At the autumn samplings, the fish weighed —100 g and at that time probably had somewhat lower androgen levels than in the earlier study. buy flovent inhaler
At the start of the experiments, previously mature males (both experiments) and immature males (experiment 2) were dissected. Operated fish were dissected in September in experiment 1 and dissected in July, September, and November (spawning period) in experiment 2. Fish were measured to the nearest 1 mm and weighed to the nearest 0.1 g under —0.1% 2-phenoxyethanol anesthesia. Blood samples were taken by means of severing the caudal peduncle and collecting the blood in heparinized tubes.