Effects of light and of testosterone derivatives or antiandrogens on the secretory content of the subcommissural organ of the quail, Coturnix coturnix japonica.

Photosensitivity of the quail subcommissural organ (SCO) is demonstrated. When the birds are submitted to continuous light the SCO cells appear depleted in secretory material and the enzyme activities investigated are of greater intensity. Such a diminished secretory content is observed in birds exposed to short daylength when they are injected with testosterone derivatives. Besides, injections of antiandrogenic compounds in continuously illuminated quails abolish the decrease of the secretory material induced by photostimulation. These results indicate that the SCO responsiveness to light appears to be mediated by some hormonal mechanism. Moreover it is more than a generalized metabolic effect: the response to antiandrogen injections suggests indeed that the SCO is a likely target organ for hormonal action.