Chamras H, Hershman J M
Endocrinology Research Laboratory, Wadsworth Veterans Administration Medical Center, Los Angeles, California 90073.
Am J Med Sci. 1990 Jul;300(1):16-21. doi: 10.1097/00000441-199007000-00004.
The effect of streptozotocin-induced diabetes on thyrotropin (TSH) secretion was studied in vitro in male rats, using purified thyrotrophs isolated by centrifugal elutriation. The development of diabetes was associated with a significant fall in serum T4 (4.9 +/- 1.5 vs. 1.2 +/- 0.7 micrograms/dl, control vs. diabetic), T3 (59 +/- 16 vs. 20 +/- 9 ng/dl) and TSH (53 +/- 22 vs. 23 +/- 18 microU/ml). In vitro, basal TSH release was lower in cells from diabetic rats (1570 +/- 248 microU/10(6) cells) than in controls (2612 +/- 765 microU/10(6) cells) after 48 h in culture. Furthermore, thyrotropin-releasing hormone (TRH)-induced TSH release was decreased about 30% and the intracellular TSH content was also reduced 45% in diabetic rat thyrotrophs compared with controls. The addition of 200 microU/ml of insulin in the incubation media did not change the TRH-stimulated TSH release, but it decreased the basal TSH release by 42%. Preincubation of thyrotrophs with glucose (25 mM) did not impair the basal or TRH-stimulated TSH release. In the same experimental conditions, no effect of insulin or glucose was seen on the basal or TRH-stimulated TSH release from thyrotrophs of diabetic rats. Preincubation of thyrotrophs with 10, 100, or 1000 nM of T4 for 48 h decreased basal TSH release by 27%, 45%, and 48%, respectively, and reduced TRH-induced TSH release by 46%, 48%, and 55%; 100 nM T4 also reduced TRH-induced TSH release from diabetic thyrotrophs.(ABSTRACT TRUNCATED AT 250 WORDS)
采用离心淘析法分离纯化的促甲状腺激素细胞，在体外研究链脲佐菌素诱导的糖尿病对雄性大鼠促甲状腺激素（TSH）分泌的影响。糖尿病的发展与血清T4（对照组4.9±1.5 vs. 糖尿病组1.2±0.7微克/分升）、T3（59±16 vs. 20±9纳克/分升）和TSH（53±22 vs. 23±18微单位/毫升）显著下降有关。体外培养48小时后，糖尿病大鼠细胞的基础TSH释放量（1570±248微单位/10⁶细胞）低于对照组（2612±765微单位/10⁶细胞）。此外，与对照组相比，促甲状腺激素释放激素（TRH）诱导的糖尿病大鼠促甲状腺激素细胞的TSH释放减少约30%，细胞内TSH含量也降低45%。在孵育培养基中添加200微单位/毫升胰岛素对TRH刺激的TSH释放无影响，但基础TSH释放降低42%。促甲状腺激素细胞与葡萄糖（25毫摩尔）预孵育不影响基础或TRH刺激的TSH释放。在相同实验条件下，胰岛素或葡萄糖对糖尿病大鼠促甲状腺激素细胞的基础或TRH刺激的TSH释放均无影响。促甲状腺激素细胞与10、100或1000纳摩尔T4预孵育48小时，基础TSH释放分别降低27%、45%和48%，TRH诱导的TSH释放分别降低46%、48%和55%；100纳摩尔T4也降低糖尿病促甲状腺激素细胞TRH诱导的TSH释放。（摘要截断于250字）
