Pituitary Hormones 1 and 2

Question 1

What hormones are produced in the posterior pituitary?

Answer 1

AVP and Oxytocin

Question 2

What are the hormones that are producd in the anterior pituitary?

Answer 2

ACTH

GH

PRL

TSH

FSH

LH

Question 3

Describe the signalling to the pituitary gland?

Answer 3

neurons in the supraoptic and paraventricular nuclei in the hypothalamus receive signals and control release of hormones from the pituitary *hypophyseal portal system*

Question 4

How does the thyroid influence pituitary action?

Answer 4

1. Hypothalamus releases TRH
2. Pituitary gland releases TSH
3. TSH stimulates thyroid gland to make Thyroxine
4. negative feedback on hypothalamus and pituitary gland

Question 5

what would grave’s disease look like on a technetium scan?

Answer 5

smooth uptake of entire gland

• note that if it was unilobular, then only asmall part of the thyroid gland would uptake

Question 6

what occurs in hypothyroidism?

Answer 6

hypothyroidism - thyroid gland doens’t make enough thyroxine to produce negative feedback on pituitary gland and hypothalamus

Question 7

what are some clinical findings of hypothyroidism?

Answer 7

weight gain

cold intolerance

dry skin, hair

memory loss

constipation

slow pulse

outer one third of eyebrows lost

Question 8

what is the treatment for hypothyroidism?

Answer 8

give low dose thyroxine (don’t want to increase thyroxine levels too fast or they’ll end up with hyperthyroidism)

• aim to normalise TSH levels -

if heart disease use extra low dose initially and titre slowly -

*there shouldn’t be side effects of thyroxine unless you’re giving too much - in which case you run the risk of causing Afib

Question 9

what is the connection between the hypothalamus and the testes?

Answer 9

hypothalamus releases GnRH and this stimulates the pituitary to release FSH (sperm production) LH (testosterone production)

• this goes to the testes for their respective functions
• negative feedback, testosterone is a negative feedback to the hypothalamus

Question 10

what would you expect to find if testosterone levels are very low?

Answer 10

negative feedback on they hypothalamus is removed, therefore you get higher levels of GnRH

Question 11

what is the diagnosis if you have low testosterone and normal FSH/LH levels?

Answer 11

secondary testicular failure due to pituitary disease/tumour - if it was a primary testicular failure then we would see low testosterone and really high FSH/LH levels

Question 12

How is the pituitary gland connected to the ovaries?

Answer 12

hypothalamus produces GnRH to pituitary

pituitary producse FSH and LH

FSH -ovulation of ovaries

LH - produces estrogen in ovaries

*estrogen negative feedback on hypothalamus production of GnRH

Question 13

what occurs to your hormone levels during menopause?

Answer 13

estrogen levels drop due to ovarian failure

removes negative feedback from estrogen

increased levels of FSH and LH

Question 14

What is the diagnosis if low estrogen, and really high FSH and LH?

Answer 14

menopause

Question 15

what is the diagnosis of low estrogen level and low FSH and LH?

Answer 15

anorexia, extreme exercise, pituitary tumour

Question 16

describe the hypothalamo-pituitary adrenal axis

Answer 16

• hypothalamus produces CRF
• stimulates pituitary to produce ACTH
• ACTH stimulates adrenal gland to produce cortisol
• cortisol has negative feedback on the hypothalamus and the pituitary gland

Question 17

what is the pre-hormone to ACTH?

Answer 17

pro-opiomelanocortin

*also prehorone for Beta-endorphin and melanocyte stimulating hormone

Question 18

what are the metabolic effects of cortisol

Answer 18

• negative effects bone
• inhibits growth
• effects mood - depression/psychosis
• increase cardiac output
• increase renal blood flow/glomerular filtration rate
• can cause cataracts
• modulate WBC function

Question 20

what are the consequences of the ACTH excess?

Answer 20

results in cortisol excess

hyperpigmentation

euphoria/psychosis

Question 21

What is Cushing’s syndrome?

Answer 21

cortisol excess resulting in

• hyperglycameia
• obesity
• muscle weakness
• osteoprosis
• hypertension
• irregular periods
• psychosis

Question 22

what can you use to induce production of GHRH?

Answer 22

hypoglycaemia, glucagon, arginine, stress, sleep

Question 23

Describe the growth hormone axis

Answer 23

• hypothalamus produces GHRH
• pituitary gland secretes GH
• GH works on liver to release IGF1- negative feedback on hypothalamus

Question 24

are growth hormone measurements reliable?

Answer 24

single measurements are not - they raise and drop quite randomly throughout the day - hterefore we use IGF1 most of hte time

Question 25

what are the effects of Growth hormone?

Answer 25

• linear growth
• glucose metabolism (hyperglycaema)
• lipolysis
• protein synthesis
• renal salt and water reabsorption

Question 26

what are some clinical features of acromegally? What is the cause?

Answer 26

acromegally - usually a tumour of pituitary - causes too much GH

• produces alarming skeletal growth especially during growth phase of life - if you develop this after your grwoth plates have closed it can still make your bones thicker
• see patients with large hands, prominent chins, larger tongue, larger feet etc.

treatment for this is to remove the tumour

Question 27

growth hormone deficiency can lead to what?

Answer 27

short stature -

in adults, growth hormone deficiency can lead to poor muscle funciton, fat excess, osteoporosis, cardiac disease and poor quality of life

Question 28

Describe the hormone system that produces prolactin

Answer 28

• hypothalamus produces Thyrotropin Releasing Factor
• pituitary gland produces prolactin
• prolactin induces breast milk production - and lowers FSH/LH levels = low libido and anovulation

Question 29

what has a positive feedback on prolactin relases?

Answer 29

the suckling reflex has a positive feedback on the production of prolactin

Question 30

what is the diagnosis of a woman, 2 years amenorrhoea, low libido, galactorrhoea (milk production)

bloods show very high prolactin

low estradiol

low FSH and LH

Answer 30

pituitary tumour