Abstract
The effects of oxalic acid (OA) and tartaric acid (TA) on absorption of calcium (Ca) and phosphorus (P), and on bone metabolism of an experimental osteoporosis model were studied in female Wistar rats. After rats were given 1 and 3 % of oxalic acid (OA) or tartaric acid (TA) in their drinking water for 1, 2 and 3 weeks, fecal output of Ca increased dose-dependently with OA and TA. Fecal output of P also increased or tended to increase after OA and TA treatment. To evaluate the effects of OA and TA on bone metabolism of ovariectomized (OVX) osteoporotic rats, OVX rats were given 1 % OA (OVX-OA), 1 % TA (OVX·A) or water (OVX) for 6 months. Ash/Dry weight ratio of femur and tibia decreased significantly in OVX, OVX · OA and OVX · TA compared with sham operated rats (Sham), but there was no significant difference between any two of the three groups. Contents of Ca and P decreased in OVX and very remarkably in OVX · OA and OVX · TA rats compared to the controls. Histomorphometricaly, trabecular volume in tibial epiphysis decreased in OVX · OA and OVX · TA rats compared to the controls and OVX rats. The results suggest that excessive ingestion of OA and TA might exacerbate osteoporosis due to inhibition of Ca and P absorption from the gut.
