Give the characteristics of hormones pertaining to

(i) Site of action

(ii) Chemical nature

(iii) Manner of transportation.

Mention the three types of cells of the islets of Langerhans and the name of the hormone they secrete.

Name the following conditions :

(i) Passage of much glucose in urine

(ii) Overdose of insulin makes the diabetic patient unconscious

List any three symptoms of diabetes mellitus.