Effects of oral administration of orotic acid on hepatic morphologic characteristics and serum biochemical variables in cats

Objective-To evaluate orotic acid (OA) as a possible etiologic factor in ca ts with idiopathic hepatic lipidosis (HL), Animals-20 clinically normal adult female cats. Procedure Cats were fed a control diet or a diet containing less protein. O n day 1 of the control period, blood, urine, and liver biopsy specimens wer e obtained. Each cat was given an oral dose of water daily. On days 8, 15, and 22, blood and urine specimens were collected as on day 1. On day 29, li ver, blood, and urine samples were obtained as on day 1. After a resting pe riod of 30 to 60 days, cats were treated with orotic acid. Serum biochemica l analyses, urinary OA-to-creatinine ratios, and liver biopsy specimens wer e evaluated. Cats were given OA orally (suspension or capsules) for 29 days . Sample collection and data obtained were identical to those described for the control period. Results-Urinary OA-to-creatinine ratios were significantly higher in all tr eated cats, but ratios were significantly higher in those receiving OA in c apsules than in those receiving OA in suspension. Diet or treatment did not alter hepatic biochemical or histologic variables significantly. However, 7 cats given the highest dose of OA in capsules developed azotemia, urolith iasis, and renal changes. Conclusions-Most concentrations of OA used in this study did not induce HL in cats during a 29-day period, but the highest dosage used did result in r enal disease. Clinical Relevance-Orotic acid does not appear to be involved in the genesi s of HL in cats.