The effect of manganese supply on thyroid hormone metabolism in the offspring of manganese-depleted dams

Abstract

The present study was performed to investigate the effect of manganese (Mn) supply on metabolism of thyroid hormones in the rat. A study with rats was carried out over two generations. Female rats were raised with a Mn-deficient diet (0.1 mg Mn/kg), and mated to produce a second generation. The male rats of the second generation were used as subjects for the investigation. They were divided into five groups and fed diets with Mn concentrations of 0.1, 0.5, 2.2, 10, and 46 mg/kg for 40 d. For assessment of thyroid hormone metabolism, concentrations of thyroid hormones in serum and activity of hepatic type I 5'deiodinase (5'D-1) were measured. Feeding diets with 0.1 mg Mn/kg impaired growth and food conversion, influenced parameters of thyroid hormone metabolism, and changed some clinical-chemical parameters, such as concentrations of total protein, albumin, calcium (Ca) and magnesium (Mg) as well as activity of alkaline phosphatase in serum. Regarding the thyroid hormone metabolism, rats fed the diet with a Mn level of 0.1 mg/kg had a higher 5'D-I activity in liver, and consequently a higher concentration of triiodothyronine in serum than the rats fed the other diets. In contrast, the concentrations of total and free thyroxine were not influenced by the Mn intake. Growth, clinical-chemical parameters, concentrations of thyroid hormones in serum, and activity of hepatic 5'D-I were similar in the rats fed diets with Mn concentrations between 0.5 and 64 mg/kg. The present study shows that feeding a diet with a very low Mn concentration affects growth and thyroid hormone metabolism and that a dietary level of 0.5 mg Mn/kg is adequate for growth and thyroid hormone metabolism in the offspring of Mn-depleted dams.

Effects of environmental temperature and dietary manganese on egg production performance, egg quality, and some plasma biochemical traits of broiler breeders1

“…Obviously, the correlations between dietary Mn and the activities of tissue TSOD, MnSOD, and copper-zinc superox ide dismutase in broiler breeders need to be further investigated. In addition, dietary Mn induced a signifi cant decrease in plasma T 3 level in the current study, which further confirmed the previous results in rats (Buthieau and Autissier, 1983;Eder et al, 1996). Fur thermore, the results from both Eder et al (1996) and Van der Geyten et al (1999) implied that the decreased plasma T 3 level due to Mn supplementation might be related to the decreased hepatic 5′-deiodinase enzyme activity, which is a key enzyme of thyroid hormone metabolism in converting T 4 into the biological active T 3 .…”

“…In addition, dietary Mn induced a signifi cant decrease in plasma T 3 level in the current study, which further confirmed the previous results in rats (Buthieau and Autissier, 1983;Eder et al, 1996). Fur thermore, the results from both Eder et al (1996) and Van der Geyten et al (1999) implied that the decreased plasma T 3 level due to Mn supplementation might be related to the decreased hepatic 5′-deiodinase enzyme activity, which is a key enzyme of thyroid hormone metabolism in converting T 4 into the biological active T 3 . The decreased plasma T 3 level might be involved in the improvement of thermotolerance, because hy perthyroidism accelerated the basal metabolic rate and oxidative metabolism and then resulted in oxidative damage (Asayama et al, 1987;Pereira et al, 1994).…”

Evaluation of manganese uptake and toxicity in mouse brain during continuous MnCl2 administration using osmotic pumps

“…We also observed Mn 2+ accumulation in other organs of the head and neck region, which are not shielded by the bloodbrain barrier, such as the pituitary, thyroid and other endocrine glands. Although the specific function of Mn 2+ in these glands is not fully elucidated, it seems to be involved in important processes such as protection against oxidative injury (26,27) and post-translational modifications of components in the secretory pathway, such as those involved in thyroid hormone production (28)(29)(30).…”

Malignant Ovine Theileriosis: Alterations in the Levels of Homocysteine, Thyroid Hormones and Serum Trace Elements

“…In theileriosis, schizontinfected cells may disseminate through the lymphoid tissues into thyroid glands and cause damage [9]. On the other hand, there are reports that changes in some of the micronutrients (selenium, copper, cobalt, zinc, manganese, and iodine) affect thyroid function [10][11][12]. In addition, recent studies evidenced that the decrease in the serum trace elements during ovine theileriosis, could interfere with the protective antioxidant mechanisms of RBCs [13], resulting in the anaemia.…”