The effects of thyroid-stimulating hormone, estradiol and prolactin on sodium/iodide symporter mRNA expression in mouse lactating mammary gland cells under different iodine levels

Abstract

Objective The present study investigated the sodium/iodide symporter mRNA expression in mouse lactating mammary gland cells under different iodine levels and the effects of thyroid-stimulating hormone (TSH), estradiol (E2) and prolactin (PRL) on NIS mRNA expression in mouse lactating mammary gland cells. Methods Mouse lactating mammary gland cells were cultured in vitro and stimulated with different concentrations of iodine (0, 5, 50, 3 000, 10 000 μg/L; 50 μg/L was the control group) for 24 h, and the followings were added to the culture medium, iodine plus TSH (10 μg/L), iodine plus E2 (100 μg/L) and iodine plus PRL (100 μg/L). After cultured for another 24 h, total RNA was extracted, the expression of NIS mRNA in mouse lactating mammary gland cells were detected by real-time quantitative PCR. Results The NIS mRNA expression levels of the mammary gland cells stimulated with 0, 5 μg/L of iodine (0.016 5 ± 0.001 6, 0.015 8 ± 0.002 7) were significantly higher than that of the control group (0.011 9 ± 0.001 0, all P < 0.01). Under the iodine concentration of 0 μg/L, the NIS mRNA expression level in the iodine plus TSH group (0.021 6 ± 0.002 4) was significantly higher than that of the cells with iodine alone (0.016 5 ± 0.001 6, P < 0.01). The NIS mRNA expression in the iodine (0, 5, 50, 3 000, 10 000 μg/L) plus E2 groups (0.023 4 ± 0.004 5, 0.018 8 ± 0.001 2, 0.015 3 ± 0.001 4, 0.013 0 ± 0.001 3, 0.012 4 ± 0.000 6) were significantly higher than those of the cells with iodine alone (0.016 5 ± 0.001 6, 0.015 8 ± 0.002 7, 0.011 9 ± 0.001 0, 0.009 8 ± 0.001 0, 0.010 6 ± 0.000 7, all P < 0.05). The expression of NIS mRNA in the iodine (0, 50, 3 000 μg/L) plus PRL groups (0.019 0 ± 0.001 2, 0.014 7 ± 0.001 3, 0.011 8 ± 0.001 2) were higher than that of iodine alone group under 0, 50, 3 000 μg/L iodine concentrations (0.016 5 ± 0.001 6, 0.011 9 ± 0.001 0, 0.009 8 ± 0.001 0, all P < 0.05). Conclusions TSH has up-regulated the NIS mRNA expression in mammary gland cells under the condition of severe iodine deficiency. At different levels of iodine nutrition, E2 and PRL have stimulated the NIS mRNA expression. Key words: Iodine; Sodium/iodide symporter; Thyroid stimulating hormone; Estradiol; Prolactin