Which of the following hormones is insufficient in diabetes insipidus?

In diabetes insipidus, the primary issue is a deficiency or insufficient secretion of antidiuretic hormone (ADH), also known as vasopressin. This hormone is vital for regulating the body's retention of water by increasing water reabsorption in the kidneys. When ADH levels are low, the kidneys cannot conserve water effectively, leading to excessive urination (polyuria) and an increase in thirst (polydipsia).

The condition can result from various causes, including damage to the hypothalamus or pituitary gland, which produces and releases ADH. Without adequate levels of ADH, the kidneys lose the ability to concentrate urine, leading to the hallmark symptoms of diabetes insipidus.

While growth hormone, insulin, and thyroid hormones play crucial roles in various metabolic functions, they are not directly related to the water balance mechanism that ADH governs. Therefore, the insufficiency of antidiuretic hormone is the key pathology in diabetes insipidus, making it the correct answer to the question.