thyronines and 3-3--5-triiodothyronamine

Topics: Animals; Diiodothyronines; Hepatocytes; Humans; Islets of Langerhans; Thyroid Epithelial Cells; Thyronines; Triiodothyronine

Background 3-Iodothyronamine (T1AM) is an endogenous messenger chemically related to thyroid hormone. Recent results indicate significant transcriptional effects of chronic T1AM administration involving the protein family of sirtuins, which regulate important metabolic pathways and tumor progression. Therefore, the aim of this work was to compare the effect of exogenous T1AM and 3,5,3'-triiodo-L-thyronine (T3) chronic treatment on mammalian sirtuin expression in hepatocellular carcinoma cells (HepG2) and in primary rat hepatocytes at micromolar concentrations. Materials and methods Sirtuin (SIRT) activity and expression were determined using a colorimetric assay and Western blot analysis, respectively, in cells treated for 24 h with 1-20 μM T1AM or T3. In addition, cell viability was evaluated by the MTTtest upon 24 h of treatment with 0.1-20 μM T1AM or T3. Results In HepG2, T1AM significantly reduced SIRT 1 (20 μM) and SIRT4 (10-20 μM) protein expression, while T3 strongly decreased the expression of SIRT1 (20 μM) and SIRT2 (any tested concentration). In primary rat hepatocytes, T3 decreased SIRT2 expression and cellular nicotinamide adenine dinucleotide (NAD) concentration, while on sirtuin activity it showed opposite effects, depending on the evaluated cell fraction. The extent of MTT staining was moderately but significantly reduced by T1AM, particularly in HepG2 cells, whereas T3 reduced cell viability only in the tumor cell line. Conclusions T1AM and T3 downregulated the expression of sirtuins, mainly SIRT1, in hepatocytes, albeit in different ways. Differences in mechanisms are only observational, and further investigations are required to highlight the potential role of T1AM and T3 in modulating sirtuin expression and, therefore, in regulating cell cycle or tumorigenesis.

Topics: Animals; Cell Survival; Cells, Cultured; Down-Regulation; Hep G2 Cells; Humans; Mitochondrial Proteins; Rats; Rats, Wistar; Sirtuin 1; Sirtuins; Thyronines; Triiodothyronine

To study the influence of excessive iodine intake on thyroid hormones in cerebrum of filial mice and intervention of selenium.. 60 Balb/c mice were divided randomly into 4 groups: control group, iodine group, selenium group and iodine plus selenium group and given tap water, tap water containing iodine 3000 microg/L, tap water containing selenium 200 microg/L and tap water containing iodine plus selenium 200 microg/L respectively as drinking water. At the end of the fourth month, the mice mated. Thyroid hormones and TSH in serum and in cerebrum of filial mice were determined at the postnatal 0, 14th and 28th day.. At the postnatal 14th day, serum TT4 level was lower significantly, and serum TSH was higher in iodine group than those in control group and in the iodine plus selenium group. At the postnatal 0 day and 14th day, thyroid hormone concentrations in the cerebrum of progeny of mice were lower significantly in iodine group than those in control group, selenium group and iodine plus selenium (P < 0.05). No significant difference was observed among the four groups in TT4, TT3 and rT3 concentrations in serum and cerebrum at the postnatal 28th day.. Excessive iodine intake can change thyroid hormone concentrations in the cerebrum of progeny of mice and selenium supplementation exerted favorable effects on it.

Topics: Animals; Animals, Newborn; Cerebrum; Female; Iodine; Male; Mice; Mice, Inbred BALB C; Pregnancy; Prenatal Exposure Delayed Effects; Random Allocation; Selenium; Thyroid Hormones; Thyronines; Thyrotropin; Triiodothyronine

Topics: Animals; Intestinal Mucosa; Rats; Thyronines; Triiodothyronine