Enhanced hypoosmoregulatory response to growth hormone after cortisol treatment in immature rainbow trout,Salmo gairdneri |
| |
| Authors: | Steffen S Madsen |
| |
| Institution: | (1) Institute of Biology, Odense University, DK-5230 Odense M, Denmark |
| |
| Abstract: | The growth-independent effect of ovine growth hormone (oGH) and oGH + cortisol treatment on seawater (SW) adaptation in immature
rainbow trout, Salmo gairdneri was investigated. Fish were injected every second day with saline, 2.0 μg oGH/g or 2.0 μg oGH + 8.0 μg cortisol/g for a maximum
of 8 injections in freshwater (FW). Subgroups were transferred to 28‰ SW after 4 or 8 injections, and changes in plasma Na+ and Cl−, muscle water content and gill Na+/K+-ATPase activity were measured. In both of the hormone-treated groups retained in FW, gill Na+/K+-ATPase activity and interlamellar chloride cell density increased. The effects were most pronounced in the oGH + cortisol
group after 2 weeks of treatment. After transfer to SW most of the control fish died due to the osmotic stress, whereas in
the hormone-treated groups, mortality was low and there was a positive correlation between pretransfer gill Na+/K+-ATPase and the ability to maintain ionic-osmotic homeostasis after SW transfer. After two weeks of oGH + cortisol treatment,
gill Na+/K+-ATPase activity was maximal. In contrast, after SW transfer, Na+/K+-ATPase activity increased further in the oGH-treated group. This group regulated ionic-osmotic parameters less effectively
than the oGH + cortisol-treated group. The data indicate that GH and cortisol are important hormones in the regulation of
hypoosmoregulatory mechanisms in S. gairdneri. |
| |
| Keywords: | growth hormone cortisol gill Na+/K+-ATPase chloride cells hypoosmoregulation |
| 本文献已被 SpringerLink 等数据库收录！ |
|
