Answer:
Antidiuretic hormone (ADH); Hyposecretion of ADH causes frequent urination and dehydration.
Step-by-step explanation:
The antidiuretic hormone is released in blood by the posterior pituitary gland and serves to stimulate the water reabsorption at the collecting duct of kidneys. It results in the formation of concentrated urine and lesser loss of water from the body. ADH is released in the blood when the person is dehydrated or does not intake enough water.
Hyposecretion of ADH results in the production of the copious amount of urine and loss of lots of the water from the body. The person feels thirsty due to lower water levels of the body and develops insomnia. Therefore, the given symptoms of the patient are due to the insufficient secretion of ADH from the posterior pituitary.