Effect of Long-term, Low-dose Sodium Nitrate Administration on Serum Liver Enzymes Levels in Ovariectomized Rats

Introduction: High prevalence of liver disorders has been observed in postmenopausal women. This study aims at determining the effects of long-term, low-dose nitrate administration on serum levels of liver enzymes, including aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) in ovariectomized rats. Materials and Methods: Female Wistar rats were divided into three groups (n=10/group): control, ovariectomized, and ovariectomi­zed+nitrate. The ovariectomized model (ovariectomy) was induced in 6-month-old female rats using the two-dorsolateral skin incision method. The control and ovariectomized rats received drinking water, and the ovariectomized+nitrate rats received sodium nitrate (100 mg/L in drinking water) for nine months. Body weight, food intake, and water consumption were measured in all the groups at the start (month 0, the beginning of sodium nitrate administration) and end of the study (month 9, the end of sodium nitrate administration). Serum levels of AST, ALP, and ALT were measured every month. Results: Nitrate administration decreased body weight in the ovariectomized group at the end of the study (6.9%, P = 0.004) but did not affect water consumption and food intake. At the end of the study, the ovariectomized rats had increased serum levels of AST (21.1%, P<0.001), ALP (22.8%, P=0.004), and ALT (31.3%, P<0.001). Nitrate administration decreased serum levels of ALT (9.4%, P=0.029), AST (6.7%, P=0.012), and ALP (13.1%, P=0.001) over the period of the study. Conclusion: Long-term, low-dose nitrate administration improved liver function in the ovariectomized rats.