Anterior Pituitary Gland

Question 1

• What hormones are produced by the anterior pituitary gland?

Answer 1

TSH, ACTH, FSH, LH, somatotropin (GH), prolactin (PRL)

Question 2

• What cell types are found in the pars distalis & pars intermedia?

Answer 2

Pars distalis – thyrotropes (TSH), corticotropes (ACTH), gonadotropes (FSH & LH), somatotropes (GH), lactotropes (PRL)
Pars intermedia – melanotropes (MSH)

Question 3

• Which cells stain well and which stain poorly?

Answer 3

Chromophobes stain poorly, chromophils stain well (acidophils and basophils)

Question 4

• Which cell types of the pars distalis are acidophils & basophils?

Answer 4

Acidophils – somatotropes (GH), lactotropes (PRL)

Basophils – thyrotropes (TSH), corticotropes (ACTH), gonadotropes (FSH & LH)

Question 5

• Which cell type is most prominent in the pars distalis?

Answer 5

Somatotropes (50%)

Question 6

• Which three hormones regulate growth hormone?

Answer 6

GHRH, somatostatin, ghrelin

Question 7

• How are lactotropes regulated?

Answer 7

Tonic inhibition by dopamine, can be stimulated by TRH

Question 8

• What is the prohormone produced by corticotropes?

Answer 8

Proopiomelanocortin (POMC)

Question 9

• How are thyrotropes regulated and what do they produce?

Answer 9

Stimulated by thyrotropin releasing hormone (TRH) to synthesize TSH

Question 10

• What happens in the pars intermedia?

Answer 10

Prohormone POMC converted into MSH

Question 11

• What determines the fate of the synthesis of POMC?

Answer 11

Localization of processing enzymes

• Prohormone convertase I – pars distalis & pars intermedia – ACTH
• Prohormone convertase II – pars intermedia – αMSH & CLIP

Question 12

• What is the difference between a closed and an open feedback loop?

Answer 12

Closed – target cells secrete hormones that affect their own secretion
Open – stopped by removal of stimulus or depletion of biochemicals

Question 13

• What is the difference between a short and a long negative feedback loop?

Answer 13

Short – hormone from pituitary gland feeds back to hypothalamus
Long – hormone from gland feeds back to hypothalamus (& pituitary gland)

Question 14

• What is an independent system?

Answer 14

A system that does not depend upon the hypothalamus or pituitary gland (e.g. glucose regulation, calcium regulation, sodium and potassium regulation, gastrointestinal enzyme secretion)

Question 15

• What are the four key classes of pituitary disorders?

Answer 15

Hormone deficiency, hormone excess, pituitary dwarfism, pituitary neoplasms

Question 16

• Why is it difficult to treat pituitary dwarfism?

Answer 16

Hormone supplementation limited due to species specificity

Question 17

• What is the difference between gigantism and acromegaly?

Answer 17

Gigantism is a disorder before adolescence, acromegaly after