EFFECT OF LOW-DOSE METHYLPREDNISOLONE ON CALCIUM BALANCE AND BONE-COMPOSITION IN RATS

Glucocorticoid induced osteoporosis has been associated with high dose s and it has been partially attributed to decreased absorption and to increased calcium excretion. The present study examined the effect of low but effective doses of methylprednisolone (MP) on calcium balance and on skeleton in rats. Total duration of the experiment 29 days. Thi rty-one male Wistar rats (MP group) were injected with 4mg/kg body wei ght MP sc at the Ist, 11th and 20th day of the experiment and 28 rats (C group) were used as matched controls. The Ist, 11th and 20th day of the experiment rats were placed in individual metabolic cages for thr ee days. Food and water consumption were measured at the 2nd and 3rd d ays after each injection; urine and faeces were collected at the same days for calcium estimation. Calcium intake and excretion after each i njection was significantly lower in the MP group as compared to contro ls. A statistically significant positive correlation between calcium c onsumption and calcium excretion was found in both groups resulting in a negative final balance. Rats were killed the 29th day. Adrenal weig ht was statistically significant lower in MP group (p<0.001). Morphome tric properties were evaluated for the right femur. No significant dif ference was found between the two groups. Mineral and calcium content was slightly increased in the MP group. According to these results, it seems that methylprednisolone while effective on HPA axis did not hav e any effect on calcium absorption and on bone calcium deposition in r ats. (C) 1997, Editrice Kurtis.