The correct answer is A. Two of the secretions of the anterior pituitary affect the sensitivity of peripheral tissues to the action of insulin. Growth hormone has a direct effect on liver and muscle to decrease insulin sensitivity.
This may be partly through a growth hormone-induced decline in insulin receptors or to unknown post-receptor defects. In excess, growth hormone is "diabetogenic," and about 25% of patients with acromegaly have diabetes. ACTH indirectly has anti-insulin effects by virtue of the cortisol secretion it evokes. Like growth hormone, cortisol also decreases insulin sensitivity in peripheral tissues. A third anterior pituitary hormone, TSH, also tends to increase blood glucose levels. In this case, the effect is probably mediated mostly through increased glucose absorption by the gut. Patients with hyperthyroidism can sometimes exhibit a postprandial glucosuria because of excessive intestinal glucose absorption. In diabetic animals, the removal of the anterior pituitary may lower blood glucose by increasing tissue sensitivity to whatever insulin remains.
Removal of the colon (choice B) should have little effect on blood glucose since dietary glucose is absorbed in the small intestine.
Sex steroids secreted by the gonads (choice C) have little effect on blood glucose concentration.
The kidney (choice D) plays an important role in reabsorbing filtered glucose. In diabetes, the tubular reabsorption maximum is exceeded and glucose spills over into the urine. The loss of glucose in the urine helps to reduce the severity of the plasma hyperglycemia. Removal of the kidneys would, if anything, make the hyperglycemia worse.
Pancreatectomy (choice E) would make the hyperglycemia worse by removing the source of any remaining insulin.
@khushboo and @step1an were correct.