Doi S Q, Sellitti D F
Laboratory of Metabolic Diseases, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD.
Peptides. 1994;15(3):475-81. doi: 10.1016/0196-9781(94)90209-7.
Thyrotropin (TSH) regulation of atrial natriuretic factor (ANF) receptors was studied in the rat thyroid follicular cell line, FRTL-5. Exposure of FRTL-5 cells to 1 mU/ml TSH for 7 days resulted in a tenfold increase in ANF receptors (Bmax = 188 fmol/mg protein) compared with control (Bmax = 18 fmol/mg protein), without affecting binding affinity. An identical treatment of porcine thyrocytes with TSH resulted in a 50% decrease in ANF binding sites. Displacement binding studies indicated that > 80% of the ANF receptors in FRTL-5 cells belong to the ANF-R1 (guanylate cyclase-coupled) receptor subtype. By contrast, > 98% of the ANF receptors in porcine thyrocytes were of the ANF-R2, or clearance, receptor subtype. Intracellular cGMP content was increased thirty-sixfold in FRTL-5 cells by 1 microM ANF, but only 2.5-fold in porcine thyrocytes. cAMP levels were unaffected by ANF in either cell type. Northern blot analysis of poly A mRNA extracted from FRTL-5 cells incubated 2 days in the presence of 100 nM ANF indicated a twofold increase in thyroglobulin mRNA content compared with control. These findings suggest that the ANF-R1 receptor, preferentially expressed in FRTL-5 cells and regulated by TSH, might play a role in regulating thyroid hormone production.
在大鼠甲状腺滤泡细胞系FRTL-5中研究了促甲状腺激素（TSH）对心房钠尿肽（ANF）受体的调节作用。将FRTL-5细胞暴露于1 mU/ml TSH中7天，与对照组（Bmax = 18 fmol/mg蛋白）相比，ANF受体增加了10倍（Bmax = 188 fmol/mg蛋白），而不影响结合亲和力。用TSH对猪甲状腺细胞进行相同处理导致ANF结合位点减少50%。置换结合研究表明，FRTL-5细胞中>80%的ANF受体属于ANF-R1（鸟苷酸环化酶偶联）受体亚型。相比之下，猪甲状腺细胞中>98%的ANF受体是ANF-R2或清除受体亚型。1 microM ANF使FRTL-5细胞内cGMP含量增加了36倍，但在猪甲状腺细胞中仅增加了2.5倍。两种细胞类型中ANF均不影响cAMP水平。对在100 nM ANF存在下培养2天的FRTL-5细胞提取的多聚A mRNA进行Northern印迹分析表明，与对照组相比，甲状腺球蛋白mRNA含量增加了两倍。这些发现表明，优先在FRTL-5细胞中表达并受TSH调节的ANF-R1受体可能在调节甲状腺激素产生中起作用。
