Abstract
Background:
Hypothyroidism is characterized by insufficient production of thyroid hormones, crucial for metabolism. It often causes adrenal gland disturbances.

Aim:
To evaluate the effect of Vitamin B12 supplementation on adrenal gland disturbances in propylthiouracil - induced hypothyroid rats.

Methods:
Forty female rats were divided into four groups. Group 1 was treated with normal saline. Group 2 received only vitamin B12. Group 3 received 50 mg/kg propylthiouracil (PTU). Group 4 received PTU and 25 µg/kg vitamin B12. At the end of the experiment and animals' dissection, serum levels of thyroid stimulating hormone (TSH), cortisol, epinephrine, and vitamin B12 were analyzed. Adrenal and thyroid glands were examined histologically.

Results:
The results of present study showed a significant increase in TSH hormone (2.23±0.44) and epinephrine hormone( 371.74± 24.29) in hypothyroid group compared to control group, while there is a significant decrease in cortisol hormone (88±17.97) and vitamin B12 (297.52 ± 12.51) in hypothyroid group B12 compared with control group , where the level of hormones in the (hypothyroid rats +B12) group became close to the level of hormones in the control group as well significantly decreased TSH and epinephrine levels and increased cortisol and vitamin B12 serum levels. Histopathology examination showed that vitamin B12 reversed adrenal gland damage caused by hypothyroidism, restoring normal tissue structure.

Conclusion:
Vitamin B12 mitigates hypothyroidism-induced adrenal gland damage by restoring hormonal balance and tissue integrity.

Key words: Adrenal gland, Cortisol, Epinephrine, Hypothyroidism, Vitamin B12