HYPERLIPIDEMIA ENHANCEMENT OF RENAL PRENEOPLASIA BUT NOT TUMOR-FORMATION IS DUE TO ELEVATED APOPTOSIS IN THE EKER RAT

The influence of a high-fat diet on the appearance of renal tumors was assessed in the Eker rat model of hereditary renal carcinoma, Examina tion of H&E-stained sections showed a significant increase in the numb er of microscopic solid adenomas in the high-fat group compared with t he low-fat group, whereas there was no significant difference in the n umber of macroscopic tumors between the two groups. Where had the tumo r buds gone? Staining for apoptotic bodies occasionally revealed apopt osis in and around the microscopic adenomas, In addition, an Eker rat renal tumor-derived cell line showed apoptosis when it was cultured wi th high concentrations of native and acetylated low-density lipoprotei n, These findings suggested that tumor buds repeatedly appeared and di sappeared in Eker rats on a high-fat diet.