Pituitary Gland

Question 1

What is the action of the pituitary-gonodal axis?

Answer 1

The function of this varies between sexes. In men there is simple negative feedback. FSH-sperm and LH- sex hormones.
In women this varies throughout cycle. In follicular phase LH-oestrogen but inteal phase LH- progesterone. The mid cycle progesterone oestrogen surge is an example of positive feedback.

Question 2

What is the problem with high levels of prolactin?

Answer 2

This can lead to lactation and menstural disturbance.

Question 3

In the pituitary axis, which gland is the primary and which is the secondary?

Answer 3

The primary gland is the gland being acted upon e.g. Adrenal, thyroid etc. The pituitary is the secondary gland.

Question 4

What is diabetes insipidus?

Answer 4

This is where water is not reabsorbed by the kidney and leads to increased serum osmolarity.

Question 5

What can cause pituitary disorders?

Answer 5

Compression of local structures or abnormal pituitary function.

Question 6

What is a pituitary tumour compressing if it causes problems with field of vision?

Answer 6

Optic chiasm

Question 7

What causes cranial nerve palsies?

Answer 7

Cavernous sinus invasion by a pituitary tumour.

Question 8

State the order in which hormones secretion is affected by excessive proliferation of cells in the pituitary.

Answer 8

Increased: GH, LSH/FSH, TSH, ACTH. Prolactin is decreased

Question 9

What disorder of the pituitary can lead to an increased secretion of prolactin?

Answer 9

A pituitary tumour.

Question 10

What is the first hormone to be affected by a tumour in the pituitary?

Answer 10

Decreased growth hormone.

Question 11

What is endocrine hyper secretion?

Answer 11

This is where there is increased secretions of all pituitary hormones and this can be caused by a benign tumour.

Question 12

What is a prolactinoma?

Answer 12

This is a prolactin secreting pituitary tumour. They can lead to menstural disturbance, galactorrhea and infertility.

Question 13

What can acromegaly be caused by?

Answer 13

This can be caused by a GH secreting pituitary tumour. It causes problems with both soft and hard tissue. Soft tissue problems will resolve after treatment.

Question 14

What are the two different forms of endocrine testing?

Answer 14

This can be either basal (looking directly at the hormone levels) or dynamic (looking at the body’s response to hormones)

Question 15

What dynamic test would we perform if we suspect hormone deficiency?

Answer 15

We would attempt to stimulate the hormone.

Question 16

Describe the growth hormone stimulation test.

Answer 16

In this the patient is made hypoglycaemic. This reduces somatostatin and so there is less negative feedback on GH and so levels should rise. For the suppression test the opposite is done and the patient is given glucose.

Question 17

Explain why ITT is used to test ACTH stimulation.

Answer 17

CRH and ACTH are both released in stressful conditions. In the body, hypoglycaemia is a stressful condition and so should lead to stimulation of the gland.

Question 18

What are the treatments for pituitary disease?

Answer 18

Control or remove tumour, control excess hormone release and replace hormone deficiencies.

Question 19

Describe the secretion of CRH and ACTH.

Answer 19

These both have pulsative release. This increases in the early morning and decreases at night.