title: Effects of gonadal steroids on the serotonin synthesis and metabolism in the early developing tilapia brain.
abstract: The effects of gonadal steroids on serotonin (5-HT) synthesis and metabolism in the early developing brain were investigated. Seven-day-old (7 days post-hatch) tilapia, Oreochromis mossambicus were continuously treated with 17beta-estradiol (E2), methyltestosterone (MT) and para-chlorophenylalanine (p-PCA) up to the age of 30 days. The brain 5-HT content, before 30 days, increased with age. The result indicates that this is a developing period of the central 5-HTergic system. During this developing period, the activity of tryptophan hydroxylase (TPH) and monoamine oxidase (MAO) was not altered by age. Both E2 and MT influence the central 5-HT content during its restricted developmental period. E2 has an initial inhibitory effect and then a facilitative effect while MT only has a facilitative effect. The initial inhibitory effect of E2 is mediated by decreasing TPH activity and increasing MAO activity to decrease the 5-HT content. The facilitative effect of both E2 and MT is suppressed by p-CPA.
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D010134:Fenclonine / Q000494:pharmacology; D008777:Methyltestosterone / Q000494:pharmacology*; D008995:Monoamine Oxidase / Q000378:metabolism; D012701:Serotonin / Q000096:biosynthesis / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D045165:Testosterone Congeners / Q000494:pharmacology*; D017210:Tilapia / Q000254:growth & development / Q000378:metabolism*; D014365:Tryptophan Hydroxylase / Q000378:metabolism