ABSTRACT
Forty adult albino rats of both sexes were used. They were divided into four equal groups. These groups were control [untreated], Li2 CO3-treated, KI-treated, and combined C03 and KI-treated groups. Li2 CO3-treated group was given 35.5 mg/kg/body weight [1/20, 5%] of the acute oral LD/50 of Li2 CO3 in rats daily, orally, for a period of 8 weeks. Histopathological examination of thyroid glands of this group showed areas of increased activity with cuboidal epithelial lining of thyroid follicles and scanty colloid in their lumina with peripheral vacuolation of the colloid. Biochemical estimation of T3 and T4 of Li2 CO3-treated group showed very highly significant increase in T3 and T4 [P <0.001] compared to the control group. KI-treated group was given 112.5 mg/kg/body weight [1/20, 50%] of the acute oral LD50 of KI [Arena, 1970] after being converted by using Paget and Barnes table [1964], daily, orally, for a period of 8 weeks. Histopathological examination of thyroid glands of this group showed normal thyroid follicles with cuboidal epithelial lining surrounding the colloid, while some areas showed increase in the size of follicles with flattened epithelial lining and appearance of vacuolations in the colloid. Biochemical estimation of T3 and T4 of KI-treated group showed significant increase in T3 [P <0.05] and very highly significant increase in T4 [P <0.001] compared to the control group