Plasma corticosterone, thyroxine and triiodothyronine level in the collared dove (Streptopelia decaocto) during the reproductive cycle.
Male and female collared doves living in their natural environment, sexually inactive or in different stages of their reproductive cycle, were collected. Plasma triiodothyronine (T3) and thyroxine (T4) were determined by radioimmunoassay (RIA), whereas the corticosterone (CRT) level was measured by competitive protein binding assay (CPBA). The plasma T3 level showed no change except in female hatching birds. The T4 content was constant in young and sexually inactive birds, while in male birds it increased in the spring in the courting period, and this tendency continued during the summer period. In male hatching birds the T4 level decreased but there was a second peak in the "lactation" period. In birds with enlarging ovaries the T4 level showed an increasing tendency; it was lower in birds with large ovaries, to reach a high value in the periovulation period. The T4 concentration decreased in hatching and "lactating" females and gradually reached the low level similar to that observed in the inactive (late autumn--winter) birds. The CRT level was higher in inactive male and female birds, than in young ones; it decreased in male birds at the beginning of the courting period but reached peak value during summer, and this was characteristic of the hatching and "lactating" birds too. The CRT concentration increased gradually in female birds with enlarging ovaries, then decreased significantly in doves with large ovaries. The CRT level increased sharply in the periovulation period than decreased in the hatching period to return to the low level characteristic of inactive birds in "lactating" birds. These changes reflect specific gonado-thyroid as well as gonado-adrenocortical relationships in the collared dove.
D000302:Adrenal Cortex / Q000502:physiology; D000818:Animals; D001717:Birds / Q000502:physiology*; D003345:Corticosterone / Q000097:blood*; D003380:Courtship; D005260:Female; D006066:Gonads / Q000502:physiology; D007774:Lactation; D008297:Male; D010060:Ovulation; D011247:Pregnancy; D012098:Reproduction; D012726:Sexual Behavior, Animal; D013961:Thyroid Gland / Q000502:physiology; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood*
D014284:Triiodothyronine; D013974:Thyroxine; D003345:Corticosterone