Abstract
Context: There is little information regarding the regulation of 11β-hydroxysteroid dehydrogenase (11β-HSD) enzymes in skeletal muscle in the setting of type 2 diabetes.
Objective: Our objective was to investigate whether there is differential mRNA expression and enzyme activity of 11β-HSD1 and 11β-HSD2 in the skeletal muscle of diabetic subjects compared with controls at baseline and in response to dexamethasone.
Design: Participants underwent muscle biopsy of vastus lateralis at baseline and after dexamethasone.
Setting: The study took place at a university teaching hospital.
Participants: Twelve subjects with type 2 diabetes and 12 age- and sex-matched controls participated.
Intervention: Subjects were given oral dexamethasone, 4 mg/d for 4 d.
Main Outcome Measures: We assessed 11β-HSD1, 11β-HSD2, and H6PDH mRNA levels by quantitative RT-PCR and enzyme activity by percent conversion of [3H]cortisone and [3H]cortisol, respectively.
Results: At baseline, mRNA levels were similar in diabetic and control subjects for 11β-HSD1, 11β-HSD2, and H6PDH. 11β-HSD1 activity was reduced in diabetic subjects (percent conversion of [3H]cortisone to [3H]cortisol was 11.4 ± 2.5% vs. 18.5 ± 2.2%; P = 0.041), and 11β-HSD2 enzyme activity was higher in diabetic subjects (percent conversion of [3H]cortisone to [3H]cortisol was 17.2 ± 2.6% vs. 9.2 ± 1.3%; P = 0.012). After dexamethasone, 11β-HSD1 mRNA increased in both groups (P < 0.001), whereas 11β-HSD2 mRNA decreased (P = 0.002). 11β-HSD1 activity increased in diabetic subjects (P = 0.021) but not in controls, whereas 11β-HSD2 activity did not change in either group. At baseline, there was a significant negative correlation between 11β-HSD1 and 11β-HSD2 enzyme activity (r = −0.463; P = 0.026).
Conclusions: The activities of skeletal muscle 11β-HSD1 and 11β-HSD2 are altered in diabetes, which together may reduce intracellular cortisol generation, potentially conferring metabolic protection.
Altered Fiber Distribution and Fiber-Specific Glycolytic and Oxidative Enzyme Activity in Skeletal Muscle of Patients With Type 2 Diabetes