The wild African giant rat is currently explored as a laboratory model for scientific research. The present study is aimed at investigating the gross morphology, histology and histochemistry of the thyroid gland of wild African giant pouched rat. Twenty wild African giant pouched rats comprising of ten males and ten females were used for this study and they were humanly sacrificed using chloroform. Their thyroid glands were removed measured, weighted processed stained with H&E and special

more »

... The result showed that the average weight the average weight of adult male and female AGR were observed to be 1210.00 ± 56.70g and 911.11 ± 24.50g respectively. The weight showed sexual dimorphism with the male significantly higher than the female. Gross morphological studies of thyroid glands showed a bi-lobed organ located on the lateral surface of the trachea. The two lobes of the gland were joined together towards the superior poles by an isthmus. The result showed that the weight of the male thyroid glands was 1.28 ± 0.03g while that of the female AGR was 1.16 ±0.01g significantly higher than that of the female African giant rat (P<0.05) hence showed sexual dimorphism. The length and width of glands do not show sexual dimorphism. Histological studies showed that the thyroid of the African giant rat consisted of follicles surrounded by follicular cells of various shapes suggesting different level of activity of the follicles. Colloids in the follicles were stained positive with periodic acid Schiff stain indicating that glycoprotein was present. Parafollicular cells were present in between the follicles of the glands similar to that of humans.