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EFFECT OF CHRONIC K + DEFICIENCY ON CONTRACTILE PROPERTIES OF SOLEUS MUSCLE IN RATS: EVIDENCE OF SEX DIFFERENCES
Author(s) -
Piyachaturawat Pawinee,
Muchimapura Suparporn,
Sophasan Samaisukh,
Jariyawat Surawat,
Pholpramool Chumpol,
Satayavivad Jutamaad,
Endou Hitoshi
Publication year - 1999
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1046/j.1440-1681.1999.03036.x
Subject(s) - medicine , endocrinology , isometric exercise , soleus muscle , skeletal muscle , chemistry , creatine kinase , biology
1. Alterations in skeletal muscle function of chronically K + ‐depleted male and female rats were investigated in isolated soleus muscles. 2. By 16 weeks K + deficiency, plasma K + concentrations in both male and female rats were reduced to approximately 2 mEq/L, which was accompanied by an approximate 50% reduction in muscle K + content and a marked increase in muscle Na + content. These changes were similar in both males and females. 3. Plasma creatine phosphokinase activity progressively increased with time in K + ‐depleted male rats, whereas only a slight increase was observed in female rats. 4. Maximum isometric twitch tension (Pt) and tetanic tension (Po) of K + ‐depleted soleus muscles from male rats was markedly suppressed; this was not seen for soleus muscles obtained from female rats. 5. After exposure to insulin in low‐K + solution, the contractile tension of soleus from the K + ‐depleted male rats was suppressed to a greater extent. 6. All alterations in muscle function during chronic K + depletion were restored to normal after 2 weeks K + repletion. 7. The results suggest that there is a preponderance for male over female rats in developing alterations in skeletal muscle function during chronic K + deficiency. The changes may be associated with abnormalities of muscle membrane permeability and cellular function.