title: Thyroid photoperiod and gonadal regression in the common myna Acridotheres tristis.
abstract: In the common myna, extirpation of the thyroid glands inhibited seasonal development of the testes of birds maintained under normal length days, but full development, similar to sham-operated birds, resulted when maintained under 15L:9D. Further, thyroidectomy delayed and reduced the rate of gonadal regression when performed in 15L:9D exposed birds having fully developed testes. The thyroid-gonad relationship exhibited in the common myna is of great adaptive value to the bird, especially in the subtropics, where sudden fluctuations in environmental temperature (due to heat wave/hail storm) may lead to sharp alterations in thyroid activity.
mesh_terms: D000818:Animals; D001717:Birds / Q000502:physiology*; D008027:Light; D008297:Male; D010507:Periodicity; D012621:Seasons; D013737:Testis / Q000502:physiology*; D013961:Thyroid Gland / Q000502:physiology; D013965:Thyroidectomy