RESUMO
The possible interaction of circadian rhythms in serum concentrations of corticosterone (B) with the response of broiler cockerels to heat stress (HS) and adrenal manipulation with adrenocorticotropic hormone (ACTH) and dexamethasone acetate (DA) was investigated. Adrenocortical response, as indicated by corticosterone concentrations, was greater early in the photoperiod in cockerels exposed to HS or injected with ACTH. A single injection of DA tended to be more inhibitory on B when administered later in the photoperiod.
Assuntos
Córtex Suprarrenal/metabolismo , Corticosterona/sangue , Córtex Suprarrenal/efeitos dos fármacos , Hormônio Adrenocorticotrópico/farmacologia , Animais , Galinhas , Corticosterona/metabolismo , Dexametasona/farmacologia , MasculinoRESUMO
An experiment was conducted to monitor fluctuations in the major adrenal steroid, corticosterone (B), and two iodinated thyroid hormones, triiodothyronine (T3) and thyroxine (T4), over the course of a 24-hr day in broiler cockerels. A circadian variation was observed in B concentrations with the highest found at 0130 hr (23 hr light: 1 hr darkness; photophase beginning at 0100 hr). No circadian variation was observed for either T3 or T4.
