Which hormone is primarily regulated by the hypothalamus-pituitary axis?

Growth hormone is primarily regulated by the hypothalamus-pituitary axis. The hypothalamus secretes growth hormone-releasing hormone (GHRH), which stimulates the anterior pituitary gland to release growth hormone (GH). Conversely, somatostatin, also released by the hypothalamus, inhibits the secretion of growth hormone. This feedback loop exemplifies the direct control the hypothalamus exerts over the production of growth hormone from the pituitary gland, demonstrating the critical role of the hypothalamus-pituitary axis in endocrine function.

In contrast, insulin is primarily regulated by blood glucose levels and is produced by the pancreas, while adrenaline, produced by the adrenal glands, is regulated by various factors including stress and neural inputs. Thyroid hormone levels are regulated by thyroid-stimulating hormone (TSH), which is also influenced by the hypothalamus-pituitary axis, but the most direct regulation pertaining to hormone secretion in this context emphasizes growth hormone.