title: A simple and rapid method for the determination of the concentrations of magnesium, sodium, potassium and sodium, potassium pumps in human skeletal muscle.
abstract: 1. For the diagnosis of electrolyte disorders, data on skeletal muscle composition are often valuable, but rarely available. We have therefore developed a simple and rapid needle biopsy procedure for the determination of the concentrations of K+, Na+, Mg2+ and Na+, K+-pumps in muscle. 2. Using a Bergström needle, biopsies weighing around 25 mg were taken from the vastus lateralis muscle of 18 normal subjects (aged 44-86 years) and extracted with trichloroacetic acid (TCA). The concentrations of K+, Na+ and Mg2+ were 90.7 +/- 1.8, 31.9 +/- 1.6 and 9.5 +/- 0.2 mumol/g wet wt., respectively (means +/- SE). 3. The TCA extraction gave the same values as digestion with 65% HNO3 or 35% H2O2, could be used over the weight range 10-55 mg and showed a Mg2+ recovery of 101.7%. 4. The concentration of Na+, K+-pumps was quantified as the total capacity for [3H]ouabain binding. In vastus lateralis biopsies obtained from six normal subjects the mean value was 258 +/- 16 pmol/g wet wt. 5. Comparison of the concentrations of K+, Mg2+ and [3H]ouabain-binding sites in samples obtained post mortem showed modest variation among different muscles with varying fibre composition. 6. Measurements of the concentrations of K+, Na+, Mg2+ and Na+, K+-pumps in duplicate biopsies of the vastus lateralis yield values which seen representative for the total pool of skeletal muscle fibres and can be performed within a few hours.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D005260:Female; D006801:Humans; D007473:Ion Channels / Q000032:analysis*; D008274:Magnesium / Q000032:analysis*; D008275:Magnesium Deficiency / Q000378:metabolism; D008297:Male; D008722:Methods; D008875:Middle Aged; D009132:Muscles / Q000032:analysis* / Q000378:metabolism; D010042:Ouabain / Q000378:metabolism; D011188:Potassium / Q000032:analysis*; D011191:Potassium Deficiency / Q000378:metabolism; D012964:Sodium / Q000032:analysis*; D014020:Tissue Extracts / Q000032:analysis; D014238:Trichloroacetic Acid
chemical_list: D007473:Ion Channels; D014020:Tissue Extracts; D010042:Ouabain; D014238:Trichloroacetic Acid; D012964:Sodium; D008274:Magnesium; D011188:Potassium