Hormones Secreted by the Pituitary Gland
The pituitary gland secretes nine distinct hormones divided between its anterior and posterior lobes: the anterior pituitary produces thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), prolactin, growth hormone (GH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH), while the posterior pituitary releases oxytocin and antidiuretic hormone (vasopressin). 1
Anterior Pituitary Hormones
The anterior pituitary (adenohypophysis) contains five specialized cell types, each producing specific hormones under hypothalamic control:
Thyroid-Stimulating Hormone (TSH): Produced by thyrotropes, TSH regulates thyroid gland function and thyroid hormone production 1, 2
Adrenocorticotropic Hormone (ACTH): Secreted by corticotropes, ACTH controls cortisol release from the adrenal glands 1, 3
Prolactin (PRL): Released by lactotropes, prolactin primarily regulates lactation and milk production 1, 4
Growth Hormone (GH): Produced by somatotropes, GH is essential for post-natal growth, development, and metabolism 1, 5
Gonadotropins: The gonadotropes secrete two hormones—follicle-stimulating hormone (FSH) and luteinizing hormone (LH)—which regulate reproductive function, gonadal hormone production, and gametogenesis 1, 6
These anterior pituitary hormones are secreted under the influence of hypothalamic releasing and inhibiting factors delivered through the hypothalamic-pituitary portal system 1, 7
Posterior Pituitary Hormones
The posterior pituitary (neurohypophysis) differs fundamentally from the anterior lobe—it consists of axonal terminations from neurons whose cell bodies reside in the hypothalamus:
Oxytocin: Regulates uterine contractions during childbirth and milk ejection during lactation 1, 2
Vasopressin (Antidiuretic Hormone, ADH): Controls water balance, blood pressure regulation, and fluid homeostasis 1, 2
These hormones are synthesized in hypothalamic neurons and transported down axons for storage and release in the posterior pituitary 3, 6
Additional Pituitary Hormone
- Melanocyte-Stimulating Hormone (MSH): The intermediate lobe (pars intermedia) produces MSH, though this lobe is rudimentary in humans 3, 6
Clinical Context
The hypothalamus exerts precise control over anterior pituitary hormone secretion through trophic factors, while directly producing the hormones released from the posterior pituitary 1. The hypothalamus also participates in complex regulation of food intake, temperature, sleep, arousal, memory, thirst, and other autonomic functions 1. Pituitary dysfunction can manifest as either hypopituitarism (hormone deficiency affecting 25-35% of patients with pituitary adenomas across multiple axes) or hyperpituitarism (hormone excess, typically from adenomas) 5.