Carr B L, Chiasson R B
Gen Comp Endocrinol. 1983 Apr;50(1):18-23. doi: 10.1016/0016-6480(83)90238-1.
Pituitary cyclic AMP-dependent protein kinase (cAMP-PK) activity ratios are not increased in response to thyrotropin-releasing hormone (TRH) in old chickens (retired White Leghorn breeders). This reduced responsiveness may be due to reduced hypothalamic function, reduced thyrotrope function, or to a reduction in TRH membrane receptors. The thyroid cAMP-PK activity ratio of old males does not respond to TRH treatment but the thyroid of old females does have an increased activity ratio ater TRH injection. Both males and females have a much higher basal cAMP-PK activity ratio than young birds. This higher basal level is thought to be due to an increased thyroid-stimulating hormone (TSH) stimulation, and the failure of old males to increase activity after TRH injections may be due to a loss of the thyroid's ability to respond to direct TRH stimulation.
老年鸡（退役白来航种鸡）垂体中依赖环磷酸腺苷的蛋白激酶（cAMP-PK）活性比率对促甲状腺激素释放激素（TRH）无反应性增加。这种反应性降低可能是由于下丘脑功能减退、促甲状腺细胞功能减退或TRH膜受体减少所致。老年雄性鸡的甲状腺cAMP-PK活性比率对TRH治疗无反应，但老年雌性鸡的甲状腺在注射TRH后活性比率增加。雄性和雌性的基础cAMP-PK活性比率均比幼鸡高得多。这种较高的基础水平被认为是由于促甲状腺激素（TSH）刺激增加所致，老年雄性鸡在注射TRH后活性未能增加可能是由于甲状腺对直接TRH刺激的反应能力丧失。
