Thyroid
The largest of the hormone secreting (endocrine) glands located in the neck; it regulates metabolism,
- hyperthyroid excessive production of thyroid hormones, often seen in older dogs, causing excessive thirst, weight loss, increased appetite and restlessness,
- hypothyroid decreased production of thyroxine, causing poor coat, weight gain, mental dullness, fatigue, cold intolerance, and infertility,