Garthwaite T L, Kalkhoff R K, Guansing A R, Hagen T C, Menahan L A
Endocrinology. 1979 Nov;105(5):1178-82. doi: 10.1210/endo-105-5-1178.
Genetically obese hyperglycemic mice (ob/ob) were compared with their nonlittermate lean controls at 4-5 months of age with regard to brain serotonin, pituitary ACTH content, and circulating levels of glucose, glucagon, insulin, TSH, T3, T4, total tryptophan and free tryptophan. Brain serotonin pituitary ACTH content, and plasma insulin, glucose, total tryptophan, and free tryptophan were all significantly higher in obese mice than in the controls. TSH, T3, and T4 were not significantly different in obese mice vs. controls, suggesting that the obese mouse is euthyroid. Fasting improved but failed to normalize the glucose and insulin levels or insulin to glucagon ratios. Since serotonin is an important neurotransmitter with regard to hypothalamic-pituitary function and since its levels in the brain are dependent on the availability of tryptophan, the findings of elevated levels of free tryptophan in the plasma and serotonin in the brain of the obese hyperglycemic mouse may help to explain some of the previously observed abnormalities of pituitary hormone secretion in these animals.
将4至5月龄的遗传性肥胖高血糖小鼠（ob/ob）与其非同窝瘦型对照小鼠在脑血清素、垂体促肾上腺皮质激素（ACTH）含量以及葡萄糖、胰高血糖素、胰岛素、促甲状腺激素（TSH）、三碘甲状腺原氨酸（T3）、甲状腺素（T4）、总色氨酸和游离色氨酸的循环水平方面进行了比较。肥胖小鼠的脑血清素、垂体ACTH含量以及血浆胰岛素、葡萄糖、总色氨酸和游离色氨酸均显著高于对照组。肥胖小鼠与对照组相比，TSH、T3和T4无显著差异，提示肥胖小鼠甲状腺功能正常。禁食改善了但未能使葡萄糖和胰岛素水平或胰岛素与胰高血糖素的比值恢复正常。由于血清素是一种与下丘脑-垂体功能有关的重要神经递质，且其在脑中的水平取决于色氨酸的可用性，肥胖高血糖小鼠血浆中游离色氨酸水平升高以及脑中血清素水平升高的发现可能有助于解释先前在这些动物中观察到的一些垂体激素分泌异常现象。
