Endocrine: Pituitary Anatomy & Physiology

Hypothalamus Hormones

Hypothalamus Hormone Secretion

Corticotropin Releasing Hormone (CRH)
- Stimulates ACTH Release in Adenohypophysis
Thyrotropin Releasing Hormone (TRH)
- Stimulates TSH Release in Adenohypophysis
Growth Hormone Releasing Hormone (GHRH)
- Stimulates GH Release in Adenohypophysis
Gonadotropin Releasing Hormone (GnRH)
- Stimulates LH and FSH Release in Adenohypophysis
Dopamine (DA)
- Inhibits PRL Release in Adenohypophysis
Somatostatin (SS)
- Inhibits GH Release in Adenohypophysis
- Inhibits TSH Release in Adenohypophysis

Hypothalamus-Pituitary Complex ¹

Anterior Pituitary/Adenohypophysis

Adrenocorticotropic Hormone (ACTH)
- Stimulated by CRH from Hypothalamus
- Acts on Adrenal Cortex to Secrete Glucocorticoid Steroids
  - *See Endocrine: Adrenal Anatomy & Physiology
Thyroid Stimulating Hormone (TSH)
- Stimulated by TRH from Hypothalamus
- Inhibited by SS from Hypothalamus
- Acts on Thyroid Gland to Secrete Thyroxine Hormone
  - *See Endocrine: Thyroid Anatomy & Physiology
Growth Hormone (GH)
- Stimulated by GHRH from Hypothalamus
- Inhibited by SS from Hypothalamus
- Numerous Anabolic Effects with Increased Height, Muscle Mass & Bone Mineralization
Luteinizing Hormone (LH)
- Stimulated by GnRH from Hypothalamus
- Males: Acts on Leydig Cells of Testes to Produce Testosterone
- Females: Acts on Thecal Cells of Ovary to Promote Estradiol Production
Follicle Stimulating Hormone (FSH)
- Stimulated by GnRH from Hypothalamus
- Males: Acts on Sertoli Cells of Testes to Promote Spermatogenesis
- Females: Acts on Granulosa Cells of Ovary to Promote Follicular Growth
Prolactin (PRL)
- Main Stimulus is Suckling, Also Stimulated by TRH & VIP
- Acts on Mammary Glands to Produce Milk

Posterior Pituitary/Neurohypophysis

Antidiuretic Hormone (ADH)
- Produced in Supraoptic & Paraventricular Nuclei of Hypothalamus
- Travel Down Infundibulum & Then Secreted in Posterior Pituitary
- Secretion Stimulated by Increased Osmolality & Decreased Arterial Blood Volume
- Effects:
  - Acts on Kidney to Increase Free Water Reabsorption
  - Acts on Arterioles to Constrict & Increase Peripheral Vascular Resistance
Oxytocin
- Produced in Supraoptic & Paraventricular Nuclei of Hypothalamus
- Travel Down Infundibulum & Then Secreted in Posterior Pituitary
- Effects: Uterine Contraction in Labor & Milk Letdown

Pituitary Gland ²