What is hyperpituitarism primarily characterized by?

Hyperpituitarism is primarily characterized by the excessive secretion of one or more trophic hormones. This condition arises from an overactive pituitary gland, often due to a benign tumor known as an adenoma that stimulates the gland to produce more hormones than the body requires. The trophic hormones involved may include growth hormone, prolactin, adrenocorticotropic hormone (ACTH), and others, leading to a variety of systemic effects depending on which hormone is in excess.

For instance, an increased level of growth hormone can result in acromegaly in adults, while elevated prolactin levels can cause galactorrhea and menstrual disturbances. The hormonal imbalances created by hyperpituitarism can profoundly affect multiple body systems and often necessitate careful management and treatment.

In contrast, the other options do not accurately describe hyperpituitarism. Underproduction of hormones relates more to hypopituitarism instead. Granular changes in the pituitary gland can occur but are not defining characteristics of hyperpituitarism. Lastly, reduced levels of growth hormones also contradict the primary definition, as hyperpituitarism involves excess rather than deficiency. Thus, the context of excessive secretion clearly delineates hyperpituitarism as the correct answer.