TESTOSTERONE IS SECRETED EXTRAGONADALLY BY EUROPEAN QUAIL MAINTAINED ON SHORT DAYS

Castration of certain passerine migrants on short days prevents fat deposition in the following spring. Previously, we showed that spring fattening is independent of the presence of the testes in European quail. However, a requirement for testosterone could not be ruled out. The aim of the present study teas to compare the seasonal pattern of testosterone levels between intact and castrated quail In intact males maintained outdoors, testosterone was high during the breeding season and decreased in August. Levels were low during breeding in intact females and castrated males However all three groups showed increased testosterone levels from October to December, when luteinizing hormone was basal. High levels of testosterone were also secreted on short days by intact and castrated male quail caged individually in the laboratory. However, after transfer to long days, testosterone was very, low in castrates, while levels in the intact birds increased Thin-layer chromatography of plasma samples provided evidence that the testosterone antibody we used recognized testosterone rather than another steroid. These results suggest that European quail can secrete testosterone extragonadally. A requirement for testosterone to exert an organizational effect in winter to permit the expression of spring fattening may be a feature common to migratory birds.