Endocrine

, Volume 44, Issue 2, pp 454–464

Effects of alkali supplementation and vitamin D insufficiency on rat skeletal muscle

  • Lisa Ceglia
  • Donato A. Rivas
  • Rachele M. Pojednic
  • Lori Lyn Price
  • Susan S. Harris
  • Donald Smith
  • Roger A. Fielding
  • Bess Dawson-Hughes
Original Article

DOI: 10.1007/s12020-013-9976-0

Cite this article as:
Ceglia, L., Rivas, D.A., Pojednic, R.M. et al. Endocrine (2013) 44: 454. doi:10.1007/s12020-013-9976-0

Abstract

Data on the independent and potential combined effects of acid–base balance and vitamin D status on muscle mass and metabolism are lacking. We investigated whether alkali supplementation with potassium bicarbonate (KHCO3), with or without vitamin D3 (±VD3), alters urinary nitrogen (indicator of muscle proteolysis), muscle fiber cross-sectional area (FCSA), fiber number (FN), and anabolic (IGF-1, Akt, p70s6k) and catabolic (FOXO3a, MURF1, MAFbx) signaling pathways regulating muscle mass. Thirty-six, 20-month-old, Fischer 344/Brown-Norway rats were randomly assigned in a 2 × 2 factorial design to one of two KHCO3-supplemented diets (±VD3) or diets without KHCO3 (±VD3) for 12 weeks. Soleus, extensor digitorum longus (EDL), and plantaris muscles were harvested at 12 weeks. Independent of VD3 group, KHCO3 supplementation resulted in 35 % lower mean urinary nitrogen to creatinine ratio, 10 % higher mean type I FCSA (adjusted to muscle weight), but no statistically different mean type II FCSA (adjusted to muscle weight) or FN compared to no KHCO3. Among VD3-replete rats, phosphorylated-Akt protein expression was twofold higher in the KHCO3 compared to no KHCO3 groups, but this effect was blunted in rats on VD3-deficient diets. Neither intervention significantly affected serum or intramuscular IGF-1 expression, p70s6k or FOXO3a activation, or MURF1 and MAFbx gene expression. These findings provide support for alkali supplementation as a promising intervention to promote preservation of skeletal muscle mass, particularly in the setting of higher vitamin D status. Additional research is needed in defining the muscle biological pathways that are being targeted by alkali and vitamin D supplementation.

Keywords

Skeletal muscle Potassium bicarbonate Vitamin D Metabolic acidosis 

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Lisa Ceglia
    • 1
    • 2
  • Donato A. Rivas
    • 3
  • Rachele M. Pojednic
    • 3
  • Lori Lyn Price
    • 4
  • Susan S. Harris
    • 2
  • Donald Smith
    • 5
  • Roger A. Fielding
    • 3
  • Bess Dawson-Hughes
    • 2
  1. 1.Division of Endocrinology, Diabetes, and MetabolismTufts Medical CenterBostonUSA
  2. 2.Bone Metabolism LaboratoryJean Mayer USDA Human Nutrition Research Center on Aging at Tufts UniversityBostonUSA
  3. 3.Nutrition, Exercise Physiology, and Sarcopenia LaboratoryJean Mayer USDA Human Nutrition Research Center on Aging at Tufts UniversityBostonUSA
  4. 4.The Institute for Clinical Research and Health Policy StudiesTufts Medical Center, and Tufts Clinical and Translational Science InstituteBostonUSA
  5. 5.Comparative Biology UnitJean Mayer USDA Human Nutrition Research Center on Aging at Tufts UniversityBostonUSA

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