ABSTRACT
In animals, long-term feeding with peanut (Arachis hypogaea) seed coats causes hypertrophy and hyperplasia of the thyroid gland. However, to date there have been no detailed studies. Here, we explored the thyroidal effects of dietary peanut seed coats (PSC) in rats. The PSC has high levels of pro-goitrogenic substances including phenolic and other cyanogenic constituents. The PSC was mixed with a standard diet and fed to rats for 30 and 60 days, respectively. Animals fed with the PSC-supplemented diet showed a significant increase in urinary excretion of thiocyanate and iodine, thyroid enlargement, and hypertrophy and/or hyperplasia of thyroid follicles. In addition, there was inhibition of thyroid peroxidase (TPO) activity, 5’-deiodinase-I (DIO1) activity, and (Na+-K+)-ATPase activity in the experimental groups of rats as compared to controls. Furthermore, the PSC fed animals exhibited decreased serum circulating total T4 and T3 levels, severe in the group treated for longer duration. These data indicate that PSC could be a novel disruptor of thyroid function, due to synergistic actions of phenolic as well as cyanogenic constituents.
Subject(s)
Animal Feed/adverse effects , Animals , Antithyroid Agents/isolation & purification , Antithyroid Agents/toxicity , Arachis/chemistry , Drug Synergism , Glucosides/analysis , Glucosides/pharmacology , Glucosides/toxicity , Hyperplasia , Hypertrophy , Hyperthyroidism/blood , Hyperthyroidism/chemically induced , Iodide Peroxidase/antagonists & inhibitors , Iodine/urine , Male , Nitriles/analysis , Nitriles/pharmacology , Nitriles/toxicity , Ovule/chemistry , Polyphenols/analysis , Polyphenols/pharmacology , Polyphenols/toxicity , Rats , Rats, Wistar , Sodium-Potassium-Exchanging ATPase/antagonists & inhibitors , Thiocyanates/urine , Thyroid Gland/drug effects , Thyroid Gland/enzymology , Thyroid Gland/pathology , Thyroid Hormones/bloodABSTRACT
To investigate the effects of fluoride on the expression of thyroglobulin (TG),thyroid peroxidase(TPO),odium iodide symporter (NIS) genes in FRTL cells,FRTL cells cultured in vitro were treated in logarithmic phase with sodium fluoride at different concentration of 20.0,10.0,5.0,2.5,1.25 mg/L,respectively.After 72 h,the cells were collected and semi-quantitative RT-PCR for TG mRNA,TPO mRNA and NIS mRNA and β-actin was performed.The results showed that compared with the control cells,the expression levels of TG gene in FRTL cells treated with lower concentration of sodium fluoride increased compensatively,but decreased significantly (P<0.05) with higher concentration(>5.0 mg/L);the RT-PCR products of TPO and NIS in FRTL cells treated with all concentration of sodium fluoride reduced,some of them were significant (P<0.05).It is concluded that fluoride can reduce the expression of TG,TPO,NIS genes in thyroid cells,conseguently cause dysfunction" of thyroid in uptaking and unilizing of iodine,and synthesizing,storing,secreting of thyroid hormones.