De Pedro N, Gancedo B, Alonso-Gomez A L, Delgado M J, Alonso-Bedate M
Departamento de Biología Animal II (Fisiología Animal), Facultad de Ciencias Biológicas, Universidad Complutense, Madrid, Spain.
Pharmacol Biochem Behav. 1995 Aug;51(4):885-90. doi: 10.1016/0091-3057(95)00069-9.
In the present study we examined the effects of acute corticotropin-releasing factor (CRF) administration and refeeding treatment on glucose levels and thyroid hormones (plasma levels and thyroid contents) in 48-h food-deprived goldfish. Central CRF administration (2 micrograms) decreased food intake and the thyroid T3 free fraction, without significantly modifying either thyroid hormones bound fractions (T3 and T4) or plasma glucose levels. Subsequently, we tested whether CRF affects thyroid activity by itself, or whether this effect is mediated by CRF-induced feeding reduction. CRF treatment in fasted fish reduced thyroid-free T3 and increased thyroid-free T4, which could be mediated by a decreased intrathyroidal 5'-monodeiodinase activity. These data suggest a CRF effect upon thyroid activity independent of feeding reduction. On the other hand, refeeding after 48-h fasting caused a significant increase in thyroid free T4 content and plasma thyroid hormone levels. Thus, a relationship between nutritional status and thyroid function, which could overlap with CRF effects, cannot be discarded. Plasma glucose levels were only significantly modified by refeeding, which seems to be the signal triggering the increase in glucose titers. Our results support the existence of both CRF-thyroid activity and nutritional status-thyroid function interactions in goldfish.
在本研究中，我们检测了对禁食48小时的金鱼急性给予促肾上腺皮质激素释放因子（CRF）及再投喂处理对血糖水平和甲状腺激素（血浆水平及甲状腺含量）的影响。中枢给予CRF（2微克）可减少食物摄入量并降低甲状腺游离T3组分，而对甲状腺激素结合组分（T3和T4）及血浆葡萄糖水平均无显著影响。随后，我们测试了CRF是直接影响甲状腺活性，还是通过CRF诱导的摄食减少来介导这一效应。对禁食金鱼进行CRF处理可降低甲状腺游离T3并升高甲状腺游离T4，这可能是由甲状腺内5'-单脱碘酶活性降低所介导。这些数据表明CRF对甲状腺活性的影响独立于摄食减少。另一方面，禁食48小时后再投喂导致甲状腺游离T4含量及血浆甲状腺激素水平显著升高。因此，营养状态与甲状腺功能之间的关系（可能与CRF的作用重叠）不能被排除。血浆葡萄糖水平仅在再投喂时受到显著影响，这似乎是触发血糖水平升高的信号。我们的结果支持金鱼中存在CRF-甲状腺活性及营养状态-甲状腺功能相互作用。
