5-HYDROXYTRYPTAMINERGIC CONTROL OF TESTES DEVELOPMENT THROUGH THE ANDROGENIC GLAND IN THE RED SWAMP CRAYFISH, PROCAMBARUS-CLARKII

The possibility that 5-hydroxytryptamine (5-HT) stimulates testicular maturation in the red swamp crayfish, Procambarus clarkii, was investi gated. A series of 5-HT agonists and antagonists was used in addition to 5-HT itself. 5-HT and its agonists not only induced testicular matu ration but also development of the androgenic glands. In contrast, the 5-HT antagonists had no stimulatory effects on the testes of androgen ic gland, This stimulatory action of 5-HT is hypothesized to be indire ct, 5-HT stimulating release of the gonad-stimulating hormone, which i n turn activates the androgenic gland to synthesize and release androg enic gland hormone, and the androgenic gland hormone then triggers tes ticular maturation.