ACTA ENDOCRINOLOGICA (BUC)

Background. Lithium, a well known antimanic drug, has adverse effects on endocrine functions; but it is unknown in aged animals.\r\nAim. Untoward effects of lithium on thyroidal and extra-thyroidal thyroid hormones were investigated in adult and aged rats.\r\nMaterials and methods. Lithium was injected intraperitoneally at a dose of 2 mEq/kg\r\nbody weight daily to one group of rats for 10 days and the other for 25 days respectively. Thyroid and serum T3 and T4, and extrathyroidal liver and kidney T3and T4 levels were\r\nmeasured by ELISA. Pituitary and serum TSH-like substance was determined using a human-TSH immunoassay kit. Thyroperoxidase profile was measured spectrophotometrically.\r\nResults. Lithium decreased thyroid and serum T3 and T4 levels, and increased pituitary and serum TSH-like profiles after 10 and 25 days of treatments respectively in adult and aged rats. Thyroperoxidase activity was decreased in all the treatments of adult and aged rats. Liver\r\nand kidney T3 and T4 profiles were also decreased in lithium recipients. Lithium actions were severe after 10 days of treatment in adult rats and 25 days treatment in aged rats.\r\nConclusion. Lithium has untoward effects on thyroid and extra-thyroidal thyroid hormone synthesis irrespective of the age of rats.

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Background. Arecoline, a plant alkaloid of betel nut, is consumed by millions of people, for increased capacity of work. It causes immunosuppression, hepatotoxicity, and disturbance in antioxidant production, but it stimulates HPA axis and induces thyroid dysfunction.\r\nAim. To investigate the role of arecoline on adrenal activity, glycemia and glycogen profile in mice.\r\nMaterials and methods. Arecoline was injected intraperitoneally at a dose of 10 mg/kg body wt for 20-60 min for acute administration. In chronic administration the same dose was used daily for 15 days. Corticosterone, epinephrine, norepinephrine, blood glucose and liver glycogen profiles were measured after 20, 40 and 60 min, in acute administration and after 15 days in chronic administration.\r\nResults. Arecoline in acute administration increased corticosterone, norepinephrine and epinephrine levels and induced hyperglycemia with depletions of liver glycogen. But\r\nchronic arecoline administration with the same dose for 15 days caused ultrastructural degenerations of adrenal cortex and medulla with the elevation of corticosterone, and\r\ndepletions of norepinephrine and epinephrine levels. Arecoline also caused hypoglycemia and elevated liver glycogen. Atropine (arecoline receptor antagonist) prevented arecoline action on adrenal activity or blood glucose ? liver glycogen interaction.\r\nConclusion. The findings indicate that arecoline initially stimulates adrenal activity, but subsequently inhibits it with alterations of glycemic and glycogen profiles. Arecoline action is mediated by arecoline receptor in mice. Arecoline may have immunological action via adrenal hormonal suppression in mice.