Endocrine diseases are the diseases of the endocrine system. Endocrine System Diseases can be broadly classified into three categories. 1. Hyper-secretion of the endocrine glands 2. Hypo-secrection of endocrine gland 3. Tumours of the endocrine gland. Adrenal disorders, glucose homeostasis disorders, thyroid disorders, calcium homeostasis disorders, pituitary and sex hormone disorders are some of the most common disorders found.