Gøtzsche L S, Flyvbjerg A, Marshall S, Jørgensen K D, Weeke J
Medical University Department M (Diabetes and Endocrinology), Aarhus Kommunehospital, Denmark.
Acta Endocrinol (Copenh). 1991 Aug;125(2):219-26. doi: 10.1530/acta.0.1250219.
The effects of GH and T4 substitution on peripheral iodothyronine deiodinase activity in the liver, kidney and brown adipose tissue of hypophysectomized rats were investigated. Animals were treated with GH (140 micrograms hGH/day), T4 (3 micrograms/day), GH plus T4 (same doses), or saline. Rats were killed 0, 4, 7 or 11 days after treatment was started. Non-hypophysectomized, age-matched rats were killed after 0 and 11 days and served as controls. GH plus T4 restored body weight gain to normal, whereas GH alone and T4 alone did not. Tissue deiodinase activity and T3 concentrations were severely depressed in the hypophysectomized rats compared with non-hypophysectomized controls (to less than 10%). GH substitution in hypophysectomized rats led to a slight but significant elevation in tissue iodothyronine deiodinase activity in the liver and kidney, without concomitant increases in T3. Deiodinase activity in brown adipose tissue did not differ from that in saline-treated controls. T4 administration normalized deiodinase activity and tissue T3 content in all the evaluated tissues. GH plus T4 resulted in a lesser increase in deiodinase activity than T4 alone in the liver and kidney (p less than 0.01 at day 11), whereas no significant difference was observed in brown adipose tissue. In conclusion, GH stimulates iodothyronine deiodinase activity of the liver and kidney in hypophysectomized rats. Moreover, when GH is administered together with T4, the T4-stimulated enzyme activity in the liver and kidney is downregulated, suggesting that GH attenuates (or modulates) the T4 effect on this specific enzyme activity.
研究了生长激素（GH）和甲状腺素（T4）替代治疗对垂体切除大鼠肝脏、肾脏和棕色脂肪组织外周碘甲状腺原氨酸脱碘酶活性的影响。动物分别接受GH（140微克人GH/天）、T4（3微克/天）、GH加T4（相同剂量）或生理盐水治疗。治疗开始后0、4、7或11天处死大鼠。未垂体切除、年龄匹配的大鼠在0和11天后处死作为对照。GH加T4可使体重增加恢复正常，而单独使用GH和单独使用T4则不能。与未垂体切除的对照相比，垂体切除大鼠的组织脱碘酶活性和T3浓度严重降低（降至不到10%）。垂体切除大鼠补充GH导致肝脏和肾脏组织碘甲状腺原氨酸脱碘酶活性略有但显著升高，而T3未随之增加。棕色脂肪组织中的脱碘酶活性与生理盐水处理的对照无差异。给予T4可使所有评估组织中的脱碘酶活性和组织T3含量恢复正常。在肝脏和肾脏中，GH加T4导致的脱碘酶活性增加低于单独使用T4（第11天时p<0.01），而在棕色脂肪组织中未观察到显著差异。总之，GH刺激垂体切除大鼠肝脏和肾脏的碘甲状腺原氨酸脱碘酶活性。此外，当GH与T4一起给药时，肝脏和肾脏中T4刺激的酶活性下调，表明GH减弱（或调节）了T4对这种特定酶活性的作用。
