Pessina Paula, Fernández-Foren Andrea, Cueto Enrique, Delucchi Luis, Castillo Victor, Meikle Ana
Laboratorio de Técnicas Nucleares, Facultad de Veterinaria, Montevideo, Uruguay.
Acta Vet Scand. 2009 Aug 17;51(1):33. doi: 10.1186/1751-0147-51-33.
For the conclusive diagnosis of Cushing's Syndrome, a stimulating ACTH test or a low suppressive Dexamethasone test is used. Reports in other species than the dog indicate that plasma cortisol concentration after ACTH administration is affected by gender. We investigated the effect of gender on the cortisol response to ACTH and Dexamethasone tests in dogs.
Seven healthy adult Cocker Spaniels (4 females and 3 males) were assigned to a two by two factorial design: 4 dogs (2 females and 2 males) received IV Dexamethasone 0.01 mg/kg, while the other 3 dogs received an IV saline solution (control group). Two weeks later the treatments were reversed. After one month, ACTH was given IV (250 microg/animal) to 4 dogs (2 female and 2 males) while the rest was treated with saline solution (control group). Cortisol concentrations were determined by a direct solid-phase radioimmunoassay and cholesterol and triglycerides by commercial kits.
No effect of treatment was observed in metabolite concentrations, but females presented higher cholesterol concentrations. ACTH-treated dogs showed an increase in cortisol levels in the first hour after sampling until 3 hours post injection. Cortisol concentrations in Dexamethasone-treated dogs decreased one hour post injection and remained low for 3 hours, thereafter cortisol concentrations increased. The increase in cortisol levels from one to two hours post ACTH injection was significantly higher in females than males. In Dexamethasone-treated males cortisol levels decreased one hour post injection up to 3 hours; in females the decrease was more pronounced and prolonged, up to 5 hours post injection.
We have demonstrated that cortisol response to ACTH and Dexamethasone treatment in dogs differs according to sex.
为明确诊断库欣综合征，需进行促肾上腺皮质激素（ACTH）刺激试验或低剂量地塞米松抑制试验。除犬类外的其他物种研究报告表明，注射ACTH后血浆皮质醇浓度受性别影响。我们调查了性别对犬类ACTH和地塞米松试验中皮质醇反应的影响。
将7只健康成年可卡犬（4只雌性和3只雄性）分配到二乘二析因设计中：4只犬（2只雌性和2只雄性）静脉注射0.01 mg/kg地塞米松，而其他3只犬静脉注射生理盐水（对照组）。两周后治疗方案互换。一个月后，4只犬（2只雌性和2只雄性）静脉注射ACTH（250μg/只），其余犬接受生理盐水治疗（对照组）。采用直接固相放射免疫分析法测定皮质醇浓度，使用商用试剂盒测定胆固醇和甘油三酯浓度。
未观察到治疗对代谢物浓度有影响，但雌性犬的胆固醇浓度较高。注射ACTH的犬在采血后第1小时直至注射后3小时皮质醇水平升高。注射地塞米松的犬在注射后1小时皮质醇浓度下降，并在3小时内保持较低水平，此后皮质醇浓度升高。注射ACTH后1至2小时，雌性犬的皮质醇水平升高幅度显著高于雄性犬。在注射地塞米松的雄性犬中，皮质醇水平在注射后1小时下降至3小时；在雌性犬中，下降更为明显且持续时间更长，直至注射后5小时。
我们已证明，犬类对ACTH和地塞米松治疗的皮质醇反应因性别而异。
