Basal diet composition determines effects of supplemental selenium

Abstract

The effects of supplemental selenium (Se) in animal models of prostate cancer and diabetes may depend upon the composition of the basal diet to which Se is added. In this study, we examined effects of dietary Se and isoflavones, alone and in combination, on body weight, fat mass, and serum T3 levels. Non‐transgenic male littermates of TRAMP mice, produced for a study of tumorigenesis, were weaned to one of two Se‐adequate stock diets, either low (Zeigler Bros. Phytoestrogen‐Red. Diet I) or high (Harlan Teklad 8604) in isoflavones, or the same diets supplemented with 3.0 ppm Se as Se‐methylselenocysteine. Mice were killed at 18 weeks of age. Serum levels of T3 were measured using ELISA kits. Hepatic expression of the iodothyronine deiodinase I gene was determined by real time RT‐PCR. Values in a column not sharing a common subscript are significantly different (p < 0.05). These data show a significant interaction between isoflavones and Se, and demonstrate opposite effects of supplemental Se based on the isoflavone content of the basal diet. (Supported by NIH CA122235 to MJC). Final Body Wt (g) Abdom. Fat (g/35 g BW) T3 (pg/ml serum) Relative DIO1 Exprsn. Se − Iso 38.1 ± 4.9a 2.78 ± 0.29a 0.70 ± 0.13cd 1.0 ± 0.12b +Se − Iso 35.2 ± 4.2ab 1.75 ± 0.51bc 0.93 ± 0.11bc 1.49 ± 0.12a Se +Iso 31.4 ± 2.5b 1.23 ± 0.13c 1.99 ± 0.37a 1.47 ± 0.23a +Se +Iso 35.5 ± 2.8a 1.90 ± 0.17b 1.31 ± 0.19b 1.11 ± 0.14b