Hachimijiogan (Ba-Wei-Di-Huang-Wan), a herbal medicine, improves unbalance of calcium metabolism in aged rats

Aim of the study: Aged animals as well as elderly humans commonly exhibit calcium (Ca) shortage because of increased Ca excretion into urine and decreased intestinal Ca absorption, which induce elevation of serum PTH levels to maintain serum Ca levels between a normal physiological range. The most important organ that regulates this Ca homeostasis is the kidney. Hachimijiogan (HJG), a traditional herbal medicine in Japan and China, has been used for treating clinical diseases associated with kidney dysfunctions in elderly humans. However, the mechanisms of its pharmacological actions remain to be understood poorly. The present study was designed to examine whether HJG improves age-related unbalance of Ca metabolism at the systemic level using aged rats. Materials and methods: HJG was administered to 21-month-old aged rats for 3 months, and several parameters associated with Ca metabolism in serum and urine were measured. Results: Although HJG as well as aging itself did not affect serum Ca levels compared to young (11-week-old) rats, HJG improved increase in urinary Ca excretion and elevation of serum parathyroid hormone (PTH) levels in aged rats. However, HJG did not improve marked reduction of intestinal Ca absorption in aged rats. Conclusion: HJG showed regulating action for age-related unbalance of Ca metabolism at the systemic level. This finding would provide useful information for treating age-related several disorders associated with Ca unbalance. (C) 2009 Elsevier Ireland Ltd. All rights reserved.