Immunocytochemical studies on the LHRH system of the Japanese quail: influence by photoperiod and aspects of sexual differentiation.
Immunocytochemistry was used to determine if photoperiod and/or sex have any effect on the pattern of the luteinizing hormone-releasing hormone (LHRH) system in the brain of the Japanese quail. Immunopositive perikarya were found within three major areas of the brain: the rostral paraolfactory lobe, the preoptic, and the septal region. A quantitative analysis of LHRH cell numbers was performed on male and female quail after two photoperiodic treatments: sexually mature birds exposed to 24 weeks of 20 h light: 4 h darkness (20L:4D), and birds with a regressed reproductive system (induced by transfer from a photoregime of 20L:4D to 25 short days of 8L:16D). Two-way analysis of variance showed that short-day males display significantly (p less than 0.05) more immunopositive perikarya (607 +/- 134) than long-day males (291 +/- 114), short-day females (293 +/- 103) or long-day females (330 +/- 92). The density of LHRH-immunoreactive nerve fibres and the intensity of the immunostaining in the median eminence were always greater in long-day sexually mature quail (male and female) than in animals exposed to 25 days of 8L:16D. These results demonstrate that the LHRH system of the quail is influenced by photoperiod and mirrors sexual differentiation.
D000818:Animals; D000918:Antibody Specificity; D001921:Brain / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D002452:Cell Count; D002940:Circadian Rhythm; D003370:Coturnix / Q000378:metabolism* / Q000502:physiology; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism* / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D011784:Quail / Q000378:metabolism*; D012098:Reproduction; D012727:Sex Characteristics
D007987:Gonadotropin-Releasing Hormone