Borges M F, Abelin N M, Menezes F O, Dahia P L, Toledo S P
Department of Medicine, Federal School of Medicine of Triângulo Mineiro, Uberaba, Brazil.
Clin Endocrinol (Oxf). 1998 Jul;49(1):69-75. doi: 10.1046/j.1365-2265.1998.00478.x.
Although calcitonin (Ct) deficiency has been described in chronic autoimmune thyroiditis (CAT) it is unclear at what stage in the disease it develops. We have analysed the Ct secretory responses of patients in two different evolutionary stages of CAT, namely the goitrous and atrophic phases.
We studied the Ct response to combined calcium (2 mg/kg) and pentagastrin (0.5 microgram/kg) intravenous infusion in 27 patients with CAT and 30 normal adult controls. The cases were divided into two groups. The first comprised eleven women with CAT and goitrous subclinical hypothyroidism (GH), aged 28.6 +/- 10.1 years--at diagnosis they had increased thyroid autoantibody titres and cytological features compatible with stages 1 and 2 of Hashimoto's thyroiditis. The second comprised 16 females with CAT and an atrophic thyroid confirmed by ultrasound scan, aged 38.0 +/- 9.2 years--these patients were severely hypothyroid at diagnosis and were termed AH (atrophic hypothyroidism). Both groups (GH and AH) received replacement doses of thyroxine sufficient to restore euthyroidism for at least six months before the stimulation tests. Control group (C) consisted of 20 healthy women (A), aged 30.0 +/- 9.6 years, and 10 healthy men (B), aged 34.7 +/- 8.0 years. Serum Ct was measured by IRMA. The Ct secretory response was related to thyroid size and cytological data, when available.
Basal Ct concentrations in groups GH (0.08 ng/l, median) and AH (0.07 ng/l, median) were significantly lower than those of female controls (0.58 ng/l, median). Stimulated Ct peak values in groups GH (0.08 ng/l, median) and AH (0.19 ng/l, median) were significantly lower than those of female controls (13.61 ng/l, median). Also, both basal (2.72 ng/l, median) and stimulated Ct levels (35.73 ng/l, median) in male controls were significantly higher than in female controls given already. A positive correlation between the Ct secretory reserve and thyroid dimensions, evaluated by ultrasound scan, was found only in patients with thyroid atrophy (AH; rs = 0.61, P < 0.05).
We have found low basal and stimulated calcitonin values in patients with chronic autoimmune thyroiditis and thyroid enlargement, which represents an early phase of chronic autoimmune thyroiditis. Our data have also confirmed previous findings of deficient calcitonin secretion in advanced stages of chronic autoimmune thyroiditis in which thyroid atrophy is usually found. These findings may be associated with C-cell destruction following progressive, nonspecific follicular cell damage caused by lymphocytic infiltration and fibrosis of the gland.
虽然在慢性自身免疫性甲状腺炎（CAT）中已描述了降钙素（Ct）缺乏，但尚不清楚其在疾病的哪个阶段发生。我们分析了处于CAT两个不同演变阶段的患者的Ct分泌反应，即甲状腺肿阶段和萎缩阶段。
我们研究了27例CAT患者和30名正常成年对照者对静脉输注钙剂（2mg/kg）和五肽胃泌素（0.5μg/kg）联合刺激的Ct反应。病例分为两组。第一组包括11名患有CAT和甲状腺肿性亚临床甲状腺功能减退（GH）的女性，年龄为28.6±10.1岁，诊断时甲状腺自身抗体滴度升高，细胞学特征与桥本甲状腺炎1期和2期相符。第二组包括16名经超声扫描证实患有CAT且甲状腺萎缩的女性，年龄为38.0±9.2岁，这些患者诊断时严重甲状腺功能减退，称为AH（萎缩性甲状腺功能减退）。两组（GH和AH）在刺激试验前至少6个月接受足以恢复甲状腺功能正常的甲状腺素替代剂量治疗。对照组（C）由20名健康女性（A组），年龄为30.0±9.6岁，和10名健康男性（B组），年龄为34.7±8.0岁组成。采用免疫放射分析法测定血清Ct。如有可用数据，Ct分泌反应与甲状腺大小和细胞学数据相关。
GH组（中位数0.08ng/l）和AH组（中位数0.07ng/l）的基础Ct浓度显著低于女性对照组（中位数0.5μg/l）。GH组（中位数0.08ng/l）和AH组（中位数0.19ng/l）的刺激后Ct峰值显著低于女性对照组（中位数13.61ng/l）。此外，男性对照组的基础（中位数2.72ng/l）和刺激后Ct水平（中位数35.73ng/l）均显著高于上述女性对照组。仅在甲状腺萎缩患者（AH组）中发现，通过超声扫描评估的Ct分泌储备与甲状腺大小呈正相关（rs = 0.61，P < 0.05）。
我们发现慢性自身免疫性甲状腺炎伴甲状腺肿大患者（代表慢性自身免疫性甲状腺炎的早期阶段）的基础和刺激后降钙素值较低。我们的数据还证实了先前关于慢性自身免疫性甲状腺炎晚期降钙素分泌不足的研究结果，此阶段通常存在甲状腺萎缩。这些发现可能与腺体淋巴细胞浸润和纤维化导致的进行性、非特异性滤泡细胞损伤后C细胞破坏有关。
