Ilyés I, Yahata T, Stock M
Pediatric Department of University Medical School, Debrecen, Hungary.
Acta Biol Hung. 1991;42(4):345-55.
Brown adipocyte respiration was measured in isolated cells from hypothyroid, hyperthyroid and euthyroid Sprague-Dawley male rats. Hypothyroidism was induced by providing drinking water containing methimazole and hyperthyroidism was induced by addition of thyroid powder to the diet. Brown adipose tissue (BAT) cells were isolated by collagenase digestion and oxygen consumption (VO2) was measured by Clark type oxygen electrodes. BAT cell respiration was stimulated by selective and nonselective beta-adrenergic agonists: BRL 35135A (BRL) and Isoprenaline (ISO). Basal BAT cells respiration did not differ according to thyroid status. Maximal VO2 responses of BAT adipocytes from hypothyroid rats were significantly lower than in euthyroidism after ISO and BRL. The reduced response was more marked for ISO than for BRL. The thermogenic sensitivity was significantly greater in euthyroid than is hypothyroid cells for ISO, but not for BRL. The euthyroid-hyperthyroid differences were not significantly different. These results suggest: basal respiration of BAT cells in hypo- and hyperthyroidism does not reflect the overall changes in whole body metabolism; the decreased thermogenic response in hypothyroidism might be due to decreased beta-adrenoceptor numbers and/or decreased intracellular thyroxine-triiodothyronine conversion; changes in sensitivity to ISO and BRL in vitro reflect the changes seen in VO2 in vivo.
在来自甲状腺功能减退、甲状腺功能亢进和甲状腺功能正常的斯普拉格-道利雄性大鼠的分离细胞中测量棕色脂肪细胞呼吸。通过提供含甲巯咪唑的饮用水诱导甲状腺功能减退，通过在饮食中添加甲状腺粉诱导甲状腺功能亢进。通过胶原酶消化分离棕色脂肪组织（BAT）细胞，并使用克拉克型氧电极测量耗氧量（VO2）。BAT细胞呼吸受到选择性和非选择性β-肾上腺素能激动剂的刺激：BRL 35135A（BRL）和异丙肾上腺素（ISO）。基础BAT细胞呼吸根据甲状腺状态没有差异。在使用ISO和BRL后，甲状腺功能减退大鼠的BAT脂肪细胞的最大VO2反应显著低于甲状腺功能正常的情况。ISO的反应降低比BRL更明显。对于ISO，甲状腺功能正常的细胞的产热敏感性显著高于甲状腺功能减退的细胞，但对于BRL则不然。甲状腺功能正常与甲状腺功能亢进之间的差异不显著。这些结果表明：甲状腺功能减退和亢进时BAT细胞的基础呼吸并不反映全身代谢的总体变化；甲状腺功能减退时产热反应降低可能是由于β-肾上腺素能受体数量减少和/或细胞内甲状腺素-三碘甲状腺原氨酸转化减少；体外对ISO和BRL敏感性的变化反映了体内VO2的变化。
