Hypophysenhormone

Hypophysenhormone refers to the hormones produced by the pituitary gland, a small endocrine organ at the base of the brain. The pituitary has two functional parts: the anterior lobe (adenohypophysis) and the posterior lobe (neurohypophysis). Together they regulate growth, metabolism, reproduction, and water balance by releasing a set of peptide hormones or storing and releasing hypothalamic hormones.

The anterior pituitary secretes several key hormones: adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone (GH), prolactin (PRL), and the gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). ACTH stimulates the adrenal cortex to produce cortisol; TSH promotes thyroid hormone synthesis; GH influences growth and metabolism via IGF-1; PRL promotes lactation and has roles in reproductive function. FSH and LH regulate gonadal function, including follicle development, ovulation, estrogen and progesterone production, and testosterone synthesis. Melanocyte-stimulating hormone (MSH) is produced in the pituitary in small amounts and has limited endocrine significance in humans.

The posterior pituitary stores and releases vasopressin (antidiuretic hormone, ADH) and oxytocin, which are synthesized in the hypothalamus. ADH increases water reabsorption in the kidneys and helps regulate circulating volume and osmolality; oxytocin stimulates uterine contractions and milk ejection, with additional roles proposed in social and reproductive behaviors.

Regulation occurs mainly through hypothalamic releasing and inhibiting hormones, with negative feedback from target organs maintaining hormonal balance. Clinically, pituitary disorders can cause hypopituitarism (deficiency of one or more hormones) or hyperpituitarism (excess production), including adenomas, prolactinomas, Cushing disease, acromegaly, and diabetes insipidus or SIADH depending on the affected hormones.