Holmäng A, Svedberg J, Jennische E, Björntorp P
Wallenberg Laboratory, Department of Medicine 1, Sahlgren's Hospital, University of Göteborg, Sweden.
Am J Physiol. 1990 Oct;259(4 Pt 1):E555-60. doi: 10.1152/ajpendo.1990.259.4.E555.
Intact or oophorectomized (OVX) female rats were given moderate doses of testosterone for 12 wk. Insulin-stimulated glucose transport with submaximal insulin concentrations was studied with the euglycemic clamp technique. Glycogen synthesis and 2-deoxy-D-glucose uptake were measured during the clamp in the extensor digitorum longus, white and red portions of the gastrocnemius, and in the soleus muscles by tracer technique. Testosterone treatment resulted in elevations of circulating testosterone, increased plasma insulin concentrations, and a marked decrease in insulin-stimulated glucose transport. In control animals, glycogen synthesis and 2-deoxy-D-glucose transport increased with increasing concentrations of type 1 fibers. Testosterone inhibited glycogen synthesis and 2-deoxy-D-glucose transport to approximately 50% in all muscles except 2-deoxy-D-glucose transport in intact rats. Glycogen synthesis in the liver was not affected. Testosterone administration also resulted in changes in muscle morphology. The relative number of type 1 fibers decreased, whereas type 2 fibers increased. This was most pronounced in red muscles. There was also a decrease in capillary density after testosterone treatment. It was concluded that testosterone administered to female rats is followed by marked insulin resistance. This is correlated to alterations in muscle morphology with fewer type 1 fibers and a lower degree of capillarization, which are both known to be characteristics of insulin-insensitive muscles.
对完整或已切除卵巢（OVX）的雌性大鼠给予中等剂量的睾酮，持续12周。采用正常血糖钳夹技术研究了在次最大胰岛素浓度下胰岛素刺激的葡萄糖转运。在钳夹过程中，通过示踪技术测量了趾长伸肌、腓肠肌的白色和红色部分以及比目鱼肌中的糖原合成和2-脱氧-D-葡萄糖摄取。睾酮治疗导致循环睾酮水平升高、血浆胰岛素浓度增加，以及胰岛素刺激的葡萄糖转运显著降低。在对照动物中，糖原合成和2-脱氧-D-葡萄糖转运随着1型纤维浓度的增加而增加。睾酮抑制了除完整大鼠的2-脱氧-D-葡萄糖转运外所有肌肉中的糖原合成和2-脱氧-D-葡萄糖转运至约50%。肝脏中的糖原合成未受影响。给予睾酮还导致肌肉形态发生变化。1型纤维的相对数量减少，而2型纤维增加。这在红色肌肉中最为明显。睾酮治疗后毛细血管密度也降低。得出的结论是，给雌性大鼠注射睾酮后会出现明显的胰岛素抵抗。这与肌肉形态的改变有关，1型纤维减少且毛细血管化程度降低，这两者都是胰岛素不敏感肌肉的已知特征。
