Malmlöf K, Johansen T
Department of Pharmacology 3, Pharmacology Research and Development, Novo Nordisk, Malov, Denmark.
Horm Metab Res. 2003 Apr;35(4):236-42. doi: 10.1055/s-2003-39480.
This work was performed to elucidate whether growth hormone (GH)-mediated loss of adipose tissue and responses in plasma insulin and leptin are modulated by diet composition. 12-month-old rats were first fed a high-fat (HF) diet or a low-fat (LF) diet for 14 weeks. After that, GH or saline was administered to rat groups that were maintained on either HF or LF diets or that were switched from the HF to the LF diet. All 6 groups had free access to food. One additional saline group was pair-fed with the GH group that was switched from the HF to the LF diet. The caloric consumption of this latter group was also translated to yet another GH group receiving restricted amounts of the HF diet. GH was given in a total dose of 4 mg/kg/d for three weeks. After sacrifice, blood was collected and tissues were excised. In groups injected with saline, the weight of excised adipose tissue was 60 +/- 4.7, 41 +/- 3.8 and 50 +/- 4.5 g in animals that continued with the HF diet, LF diet, or that were switched from HF to LF, respectively. Corresponding figures after GH treatment were significantly (p < 0.05) decreased to 38 +/- 2.7, 30 +/- 2.3, and 31 +/- 2.7 g, respectively. Pair-feeding had no effect, whereas only 26 +/- 3.0 g of adipose tissue was retrieved in rats fed restricted amounts of HF diet while receiving GH. In this group, plasma insulin and leptin were also significantly (p < 0.05) depressed compared with other GH groups, especially to the group fed the unrestricted HF diet (203 +/- 35 vs. 1345 +/- 160 pmol/l and 9.3 +/- 1.2 vs. 31 +/- 4.4 micro g/l). In conclusion, this study shows that GH mediates breakdown of adipose tissue under a variety of dietary conditions, and that induction of hyperinsulinemia can be prevented if GH treatment is combined with restricted feeding of a diet which is relatively low in carbohydrates and rich in fat. This will also promote a fall of plasma leptin.
本研究旨在阐明饮食组成是否会调节生长激素（GH）介导的脂肪组织减少以及血浆胰岛素和瘦素的反应。12月龄大鼠首先分别给予高脂（HF）饮食或低脂（LF）饮食14周。之后，对继续维持HF或LF饮食的大鼠组以及从HF饮食转换为LF饮食的大鼠组给予GH或生理盐水。所有6组大鼠均可自由进食。另外设置一个生理盐水组，该组与从HF饮食转换为LF饮食的GH组进行配对喂养。后一组的热量消耗也对应于另一个接受限量HF饮食的GH组。GH以4mg/kg/d的总剂量给药，持续三周。处死后，采集血液并切除组织。在注射生理盐水的组中，继续食用HF饮食、LF饮食或从HF转换为LF饮食的动物，其切除的脂肪组织重量分别为60±4.7、41±3.8和50±4.5g。GH治疗后相应的数据分别显著（p<0.05）降至38±2.7、30±2.3和31±2.7g。配对喂养没有效果，而在接受GH治疗且食用限量HF饮食的大鼠中，仅回收了26±3.0g脂肪组织。与其他GH组相比，该组的血浆胰岛素和瘦素也显著（p<0.05）降低，尤其是与食用无限制HF饮食的组相比（203±35 vs. 1345±160pmol/l和9.3±1.2 vs. 31±4.4μg/l）。总之，本研究表明，GH在多种饮食条件下介导脂肪组织的分解，并且如果将GH治疗与限量喂养相对低碳水化合物、高脂肪的饮食相结合，可以预防高胰岛素血症的诱导。这也将促进血浆瘦素水平的下降。
