Pineal hydroxyindole-0-methyl transferase and N-acetyl transferase during sexual maturation of coturnix quail

The enzymic activities of hydroxyindole-o-methyl transferase (HIOMT) and N-acetyl transferase (NAT) were determined in pineals of female and male Coturnix during sexual maturation. Optimum assay conditions for HIOMT was incubation of 5 μl of homogenate for 30 min at pH 7.9, while NAT was 5 μl homogenate for 15 min at pH 6.9. These enzymes were determined in pineals of Coturnix which were immature (30 d), rapidly maturing (40 d), mature (50 d) and discontinued breeders (270 d). HIOMT was significantly decreased in pineals of Coturnix undergoing rapid sexual maturation at 40 d, compared to other stages investigated. However, NAT was significantly greater in rapidly maturing and mature Coturnix compared to immatures and discontinued breeders. These results suggest that the decline in HIOMT and increase in NAT during rapid sexual maturation may be a consequence of increased gonadal activity in this species.