Metabolic changes in DOCA-salt hypertensive rats.

Area of Science:

• Physiology
• Metabolic Research
• Cardiovascular Science

Background:

• Previous studies reported altered fiber type proportion and reduced capillary-to-fiber ratio in extensor digitorus longus (EDL) and soleus (SOL) muscles of deoxicorticosterone acetate (DOCA)-salt hypertensive rats.
• Morphological changes in hypertensive rat muscles suggest underlying metabolic alterations.

Purpose of the Study:

• To investigate carbohydrate and lipid enzyme activities and substrates in EDL and SOL muscles of DOCA-salt hypertensive rats.
• To correlate metabolic changes with previously observed morphological alterations in hypertensive rat muscles.

Main Methods:

• Analysis of glucose, glycogen, triglycerides (TG), citrate synthase (CS), beta-hydroxy-acyl-CoA dehydrogenase (HAD), hexokinase (HK), lipoprotein lipase (LPL) activity and mass, lactate, and free fatty acids (FFA) in EDL and SOL muscles.
• Measurement of serum insulin, TG, cholesterol, FFA, glucose, and high-density lipoprotein-cholesterol levels in hypertensive and control rats.

Main Results:

• In SOL muscle: increased glucose, glycogen, TG; reduced CS, HAD activities; unchanged HK, LPL, lactate, FFA.
• In EDL muscle: increased glycogen, LPL mass; unchanged CS, HAD, HK, LPL activities, glucose, lactate, FFA, TG.
• Serum analysis revealed increased insulin, TG, cholesterol, FFA, and decreased glucose in hypertensive rats.

Conclusions:

• Hypertensive rats exhibit increased muscle glycogen (EDL, SOL), hyperinsulinemia, and reduced blood glucose, suggesting insulin resistance.
• Reduced oxidative capacity in SOL muscle indicates a shift towards non-oxidative glucose metabolism.
• Elevated serum TG, FFA, and cholesterol, along with increased SOL muscle TG, highlight lipid dysregulation in hypertension.