Cañas X, Fernández-López J A, Remesar X, Alemany M
Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Spain.
Int J Obes Relat Metab Disord. 1998 Aug;22(8):734-40. doi: 10.1038/sj.ijo.0800649.
To determine the effect of 3-hydroxybutyrate (3OHB) on the thermogenic response to noradrenaline (NA) in lean and genetically obese Zucker fa/fa rats.
Rats were infused with 18.7 nmol x kg(-1) x min(-1) of NA, supplemented, for 15 min, with 66.7 micromol x kg(-1) x min(-1) of R-3-hydroxybutyrate (3OHB).
Pentobarbital-anaesthetized lean and obese Zucker rats.
Aortic and interscapular brown adipose tissue (BAT) temperature; plasma NA, 3OHB, glucose and insulin levels during infusion.
The NA-induced increase in aortic and BAT temperature was more marked in lean than in obese rats. In lean rats, the rise was arrested by 3OHB; but in obese rats 3OHB had no effect. Infusion of saline, glucose or 3OHB in the absence of NA did not induce changes in either temperature. NA infusion resulted in a rapid increase in plasma NA to 45-50 nM in both groups; this plateau was maintained for up to 60 min. The presence of 3OHB decreased the plasma NA of lean rats, but did not affect the plasma NA of the obese rats. Blood 3OHB rose to 1.2 mM during 3OHB infusion in both groups, and decreased on cessation of infusion. Blood glucose levels increased with NA infusion in both groups; the presence of high 3OHB levels decreased glucose levels only in lean rats.
The changes in NA levels induced by 3OHB may help explain the effects observed on temperature and glucose. The defective thermogenic system of obese rats cannot be modulated by 3OHB, unlike thermogenesis in lean rats, on which 3OHB has a marked effect.
确定3-羟基丁酸（3OHB）对瘦型和遗传性肥胖的Zucker fa/fa大鼠去甲肾上腺素（NA）产热反应的影响。
给大鼠输注18.7 nmol·kg⁻¹·min⁻¹的NA，并在15分钟内补充66.7 μmol·kg⁻¹·min⁻¹的R-3-羟基丁酸（3OHB）。
戊巴比妥麻醉的瘦型和肥胖型Zucker大鼠。
主动脉和肩胛间棕色脂肪组织（BAT）温度；输注期间血浆NA、3OHB、葡萄糖和胰岛素水平。
NA引起的主动脉和BAT温度升高在瘦型大鼠中比肥胖型大鼠更明显。在瘦型大鼠中，这种升高被3OHB抑制；但在肥胖型大鼠中，3OHB没有作用。在没有NA的情况下输注生理盐水、葡萄糖或3OHB均未引起温度变化。两组中，NA输注均导致血浆NA迅速升高至45 - 50 nM；该平台期维持长达60分钟。3OHB的存在降低了瘦型大鼠的血浆NA，但不影响肥胖型大鼠的血浆NA。两组在输注3OHB期间血液3OHB均升至1.2 mM，并在输注停止时下降。两组中，NA输注均使血糖水平升高；高3OHB水平的存在仅在瘦型大鼠中降低了血糖水平。
3OHB引起的NA水平变化可能有助于解释观察到的对温度和葡萄糖的影响。与对瘦型大鼠产热有显著作用不同，3OHB无法调节肥胖型大鼠有缺陷的产热系统。
