Changes in Plasma LH and Testosterone Concentrations of Japanese Quail from Hatching to Sexual Maturity

Abstract

Plasma LH and testosterone concentrations of 1-70 day-old male and female quail kept under continuous light were measured by radioimmunoassays, and compared with the LH and testosterone levels of 1-42 day-old male and female chickens.Plasma LH and testosterone concentrations in male quail were low 1-35 days of age rapidly increased at 42 days of age, and reached a peak at 56 days of age. In the female quail, plasma LH concentration was the lowest at 28 days of age, started to increase at 35 days of age and reached a peak at 70 days of age. Mean age at first egg was 42 days. Plasma testosterone concentration remained at low levels until 28 days of age. It increased thereafter and reached a peak at 56 days of age.In the male chicken, plasma LH concentration started to increase at 28 days of age, whereas testosterone started to increase at 35 days of age. In the female chicken, plasma LH concentration started to increase at 28 days of age, but the level was much lower (1/5) than that of the male at 35 days of age. The plasma testosterone level remained at low levels during the ages of 1-42 days in the female.