Pituitary function

Question 1

Give five hypothalamic trophic hormones

Answer 1

Thyrotrophin releasing hormone (TRH)
Corticotropin releasing hormone (CRH)
Growth hormone releasing hormone (GHRH)
Gonadotrophin releasing hormone (GnRH)
Prolactin releasing hormone (PRH)

Question 2

Give two hypothalamic non-trophic hormones

Answer 2

Growth hormone inhibiting hormone (GHIH)
- aka somatostatin
Prolactin inhibiting hormone (PIH)
- aka dopamine

Question 3

Which hypothalamic hormone is not a peptide hormone?

Answer 3

Dopamine

Question 4

Give six hormones that are produced by the anterior pituitary gland

Answer 4

Thyroid stimulating hormone (TSH)
 - aka thyrotrophin
Adrenocorticotrophic hormone (ACTH)
 - aka corticotrophin
Follicle stimulating hormone (FSG)
 - aka gonadotrophin
Luteinisin hormone (LH)
Growth hormone (GH)
Prolactin

Question 5

Give two hormones that are produced by the posterior pituitary gland. What type of hormones are these?

Answer 5

Anti-diuretic hormone (ADH)
- aka vasopressin
Oxytocin

These are neurohormone

Question 6

Where are pituitary neurohormones synthesised?

Answer 6

Magnocellular neurones

• have their cell bodies in the hypothlamus
• axons project into posterior pituitary
• terminals end directly on capillaries; release neurohormones directly into blood stream

Question 7

Describe the function of ADH

Answer 7

Anti-diuretic hormone
Primary target tissue is the kidney
Main function is to regulate water balance
Release is triggered by high plasma osmolarity or low plasma volume / bp
Acts on kidney collecting ducts to increase water reabsorption, and on vascular smooth muscle to increase blood pressure

Question 8

Describe the function of oxytocin

Answer 8

Main function is regulation of milk ejection and uterine contraction
Stimulated in labour; release is triggered by pressure baby’s head against cervix
Also stimulated by suckling.
Acts on milk duct smooth muscle and on uterine smooth muscle (childbirth)

Question 9

What condition can be caused by underproduction of ADH (vasopressin)

Answer 9

Diabetes insipidus

Question 10

How might diabetes insipidus be diagnosed?

Answer 10

Fluid deprivation test with response to desmopressin