The effect of hydrocortisone on immature rainbow trout (Salmo gairdnerii)

Changes in plasma thyroxine, triiodothyronine and cortisol associated with starvation in rainbow trout (Salmo gairdneri)

“…The ACTH-interrenal axis has been proposed as a controlling factor, being glycogenolytic in P. Zatipinna (Ball et al 1966) and Sarotherodon mossambicus (Swallow & Fleming 1969) and gluconeogenic in A. rostrata (Butler 1973) and S. gairdneri (Robertson et al 1963). Plasma cortisol levels were not affected by prolonged starvation (and associated metabolite mobilization) suggesting that it is not involved in these processes in S. gairdneri.…”

Factors influencing the structure, function and biota of the salmonid epidermis

“…Thus, the hyperadrenocorticism may be mediated, either directly or indirectly, by other endocrine changes related to sexual maturity. There is also some experimental evidence that corticosteroids may facilitate skin infections in fish (Robertson et al 1963;Roth 1972) and it is tempting, therefore, to conclude that high levels of corticosteroids in the blood of mature brown trout are responsible for the epidermal changes that we have demonstrated. However, the available literature indicates that spawning female salmonid fish generally have higher circulating corticosteroid levels, a result confirmed in the brown trout by A. D. Pickering and P. Christie (unpublished results), whereas the male fish show the most obvious epidermal changes and are most prone to skin infections.…”

“…However, the available literature indicates that spawning female salmonid fish generally have higher circulating corticosteroid levels, a result confirmed in the brown trout by A. D. Pickering and P. Christie (unpublished results), whereas the male fish show the most obvious epidermal changes and are most prone to skin infections. Consequently, attention has been given to androgens (in particular 17a methyltestosterone) and oestrogens which, unlike cortisol, produce a hyperplastic response in the skin when applied experimentally (see Robertson et al 1963;Idler et al 1961;McBride and van Overbeeke 1971;Yamazaki 1972). Yamazaki (1972) has shown that methyltestosterone increases epidermal mucification whereas in the natural situation epidermal mucification is decreased in male fish.…”

Effects of Cortisol implants on the susceptibility and the histopathology of the responses of naive coho salmon Oncorhynchus kisulch to experimental infection with Lepeophtheirus salmonis (Copepoda: Caligidae)

“…Although hyperplasia is a common response of the fish epidermis when exposed to a wide variety of agents such as chemical pollutants, hormonal stimuli, and bacteria or viruses (see Roberts 1978), the mechanisms by which it is controlled are not understood. Cortisol may limit epithelial hyperplasia by affecting the mitotic activity of the fish epidermis.…”