| Summary: | 碩士 === 國立海洋大學 === 水產養殖學系 === 87 === The objective of the study were to investigate the regulation of corticosteriods and sex steriods on the phagocytosis in tilapia and common carp. The peripherial blood leucocytes culture system was developed for the phagocytosis experiment. The study was divided into three parts, 1) phagocytosis in vitro in tilapia, 2) phagocytosis in vivo in tilapia, 3) phagocytosis in vitro in common carp.
Five does (1pM, 0.1nM, 10nM, 1μM及0.1mM/well) of corticosteroids and sex steroids were conducted in the expriments. Cortisol, dexamethasone, triamcinolon acetonide, cortisone, aldosterone, estradiol-17β and ethylestradiol could significantly surppress phagocytosis activity in a dose-dependent manner in tilapia after 4 hours incubation. However, cortisone, aldosterone, estrone, testosterone, 11-ketotestosterone and progesterone only had less significant or no any effects on phagocytosis in tilapia. Actinomycin D and cycloheximide could block the supression effects of cortisol and estradiol on the phagocytosis in tilapia.The data suggest the cortisol and estradiol regulates phagocytosis in tilapia leucocytes through glucocorticoid receptors and estrogen receptors, respectively.
Acute cold stress had a significant effects on decreasing phagocytosis in tilapia. The lowest phagocytosis activity was observed after 4 days of cold stress, Exogenous cortisol (in vivo) also could suppress phagocytosis activity in tilapia. The phagocytosis activity of common carp only could be slightly affected by cortisol and dexamethasone but not in other steroids. The species-specific difference was suggested on the regulation of phagocytosis in teleosts.
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