Immobilization stress and daily variations of melatonin and corticosteronein the serum of ring dove (Streptopelia risoria)

A relationship between melatonin secretion and the pituitary-adrenocortical axis was investigate in the ring dove. Daily variations of the serum conce ntration of melatonin and corticosterone were measured using radioimmunoass ays. Immobilization stress induced a significant increase in both nocturnal and diurnal serum corticosterone levels as compared with control animals, unrestrained birds. In addition, the daily variations of serum melatonin we re modified in immobilized birds. These birds exhibited higher diurnal and lower nocturnal levels of serum melatonin with respect to controls. In conc lusion,, in the ring dove, immobilization stress influences the daily varia tions of both serum melatonin and corticosterone.