SEXUAL DIFFERENTIATION OF THE PHOTOPERIODIC RESPONSE IN JAPANESE QUAIL
Keyword(s):
Plasma levels of LH are generally higher in male than in female quail. This dimorphism was found to persist in quail which had been through a breeding cycle and then gonadectomized. Under long daylengths (12 h light: 12 h darkness (12L : 12D) or 16L : 8D) ovariectomized quail had plasma levels of LH that were 55–70% of those seen in castrated birds. The difference was reduced after transfer to short days (8L : 16D) when LH concentrations fell to basal levels, but again became more pronounced when the quail were restimulated with long photoperiods. Thus, the photoperiodic response system is sexually differentiated.