Iraqi Journal of Veterinary Sciences

This study was carried out to investigate the effect of induced prepubertal hyperthyroidism on the reproductive functions of male rats at the pubertal stage. Hyperthyroidism was induced by supplementing thyroxin in drinking water (0.002% w/v) and drenching of 200 μg/kg body weight. Sixty immature males (aged 50 days) were allocated to control and hyperthyroid (PH) groups, administered with distilled water and thyroxin, respectively. Each group was subdivided into three subgroups, sacrificed after 15 days (C15 and PH15), after administration for 15 days and left without treatment for 15 days (C15+ and PH15+), or after 30 days (C30 and PH30). After each period, body weight and relative weight of genital organs were recorded. Serum concentrations of thyroid stimulating hormone (TSH), thyroxin (TT4), triiodothyronine (TT3), follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone was assessed. The expression levels of testicular inha and thyroid hormone receptor (THR) genes were analyzed. Histopathological examination of testis was studied. Compared with control, PH group male rats showed decreased body weight gain and genital organ weights at all experimental periods, increased levels of serum TT4, TT3, and LH, decreased levels of TSH, FSH, and testosterone, and lower expression levels of testicular inha and THR genes. Testicular sections of PH group male rats, showed reduced germinal epithelium, vacuolation, and decreased the number of spermatocytes and Sertoli cells compared with control. In conclusion, the disturbed fluctuations of sex steroid hormones due to prepubertal hyperthyroidism might cause retardation of the testes’ development. 

This study was designed to evaluate the cytotoxic effects of cadmium chloride (CdCl₂) on thyroid and adrenal gland of male rats (Rattus norvegicus). Thirty six male rats were used and randomly into three groups each of 12 rats, the first group(G1) kept as at control. The 2nd and 3rd groups (G2 and G3) were administrated orally cdcl₂ at doses of 15 and 20 mg/kg.B.W. respectively for 6 weeks. After the treatment period, the rats were sacrificed, then thyroid and adrenal glands were removed and processed for light microscope. Light microscopic examination of thyroid gland with (15mg/kg.B.W.) showed increase in the size of follicles, some of these follicles appeared empty from any colloidal substance and heavily infiltrated by inflammatory cells, with depletion of parafollicular cells. Vaculated follicles may be clear in other sections, and showed congested blood vessels, vascularized stroma, hyperplasia of thyrocyte in rats treated with 20 mg/kg.B.w. Results also noted changes in different regions of adrenal gland related to rats exposure tocdcl₂ with 15 mg/kg.B.W., these includes cellular debris, necrosis of cortical cells, amorphous material in the zona fasciculate and focal necrosis in zona granulosa with disruption of normal structure and replaced by necrotic cells and inflammatory cells, also obvious adipocytes infiltration which appeared clear in medulla. Most changes occurred within the adrenal cortex and appeared more severity than that in the medulla region. Hypereosinophilia, pyknotic nuclei, congested blood vessels, hemorrhage, degeneration and inflammation also seen in both regions (cortex and medulla) of adrenal gland from rat exposed to cdcl₂ at 20 mg/kg.B.W.