Posterior pituitary

Looks like

The back lobe of the pea-sized pituitary, a downward extension of nerve tissue from the hypothalamus.

What it does

Releases vasopressin to save water and oxytocin for labour and milk let-down.

Keeping it well

Damage after head injury or surgery causes diabetes insipidus: large volumes of dilute urine and constant thirst, which need prompt testing.

Related conditions

• Absent periods (amenorrhoea)
• Acute liver failure
• ADHD
• Adrenal insufficiency (Addison's)
• African trypanosomiasis (sleeping sickness)
• Alcohol withdrawal and delirium tremens
• Altitude sickness
• Alzheimer's disease
• Autism spectrum disorder
• Bedwetting (nocturnal enuresis)
• Bipolar disorder
• Birth asphyxia (hypoxic-ischaemic encephalopathy)
• Body dysmorphic disorder
• Brain abscess
• Brain aneurysm
• Brain tumour (glioma & meningioma)
• Cerebral palsy
• Chronic insomnia
• Chronic neuropathic pain
• Chronic pain syndrome
• Cluster headache
• Concussion (mild TBI)
• Congenital hypothyroidism
• Cryptococcal meningitis
• Cushing's syndrome
• Delirium
• Diabetes insipidus (arginine vasopressin deficiency)
• Down syndrome (trisomy 21)
• Drowning
• Early puberty (precocious puberty)
• Eating disorders
• Encephalitis
• Epilepsy
• Essential tremor & dystonia
• Fainting (syncope)
• Febrile seizures
• Fibromyalgia
• Fragile X syndrome
• Frailty & falls in older age
• Functional (somatic) symptom disorder
• Generalised anxiety disorder
• Haemorrhagic stroke
• Heat exhaustion & heatstroke
• Hepatic encephalopathy
• High prolactin (hyperprolactinaemia)
• Huntington's disease
• Hydrocephalus
• Hyperthyroidism & Graves' disease
• Hypoglycaemia (low blood sugar)
• Hypopituitarism
• Hypothyroidism
• Intellectual disability
• Ischaemic stroke
• Japanese encephalitis
• Lead poisoning
• Long COVID (post-viral syndrome)
• Major depressive disorder
• ME/chronic fatigue syndrome
• Measles
• Medication-overuse headache
• Meningitis
• Menopause & perimenopause
• Migraine
• Multiple sclerosis
• Narcolepsy
• Neurocysticercosis
• Normal pressure hydrocephalus
• Parkinson's disease
• Phenylketonuria (PKU)
• Pituitary adenoma
• Poisoning & overdose
• Polycystic ovary syndrome
• Post-traumatic stress disorder
• Postnatal depression
• Postpartum psychosis
• Rabies
• Roseola (sixth disease)
• Schizophrenia
• Self-harm and suicidal crisis
• SIADH (inappropriate antidiuretic hormone)
• Subdural haematoma
• Substance use disorder
• Tension-type headache
• Thrombotic thrombocytopenic purpura (TTP)
• Tick-borne encephalitis
• Tics and Tourette syndrome
• Toxoplasmosis & CMV
• Transient ischaemic attack
• Traumatic brain injury (moderate to severe)
• Tuberous sclerosis complex
• Type 1 diabetes
• Vascular dementia