Hypothalamus and Pituitary Gland

Question 1

How do the hypothalamus and anterior pituitary connect?

Answer 1

Hypothalamus secretes into the Median eminence, which has a vascular link to the A.P. via Hypophyseal portal system.

Question 2

How many nuclei does the Hypothalamus have?

Answer 2

6

Question 3

What is SF-1? Why is it important?

Answer 3

Steroidogenic Factor 1. It is important for sex differentiation in Ventro-medial nucleus of Hypothalamus.

Question 4

What are the main hormones released from the hypothalamus? (7)

Answer 4

GHRH, TRH, CRH, SST, DA, GnRH, Vasopressin.

Question 5

What is GnRH? What kind of hormone is it? Where is it from? What is it’s receptor? What does it do?

Answer 5

Gonadotrophin Releasing Hormone. It is a peptide hormone from the Hypothalamus. It uses a GPCR to act on the A.P and effect LH and FSH release. Its receptor cannot be switched off, as it is missing a C terminal tail.

Question 6

What is GHRH? What kind of hormone is it? Where is it from? What is it’s receptor? What does it do?

Answer 6

Growth Hormone Releasing Hormone. It is a peptide hormone released from the Hypothalamus. It controls the secretion of Growth Hormone from A.P.

Question 7

What is Somatostatin? What kind of hormone is it? Where is it from? What is it’s receptor? What does it do?

Answer 7

Somatostatin is a peptide hormone from the Hypothalamus (also made in delta cells of Pancreas). It has GPCR. It negatively affects GH and TSH release.

Question 8

What is TRH? What kind of hormone is it? Where is it from? What is it’s receptor? What does it do?

Answer 8

Thyrotrophin Releasing Hormone. It is a peptide hormome from the Hypothalamus. It acts via GPCR. It positively acts on TSH and PRL secretion from A.P.

Question 9

What is DA? What kind of hormone is it? Where is it from? What is it’s receptor? What does it do?

Answer 9

Dopamine is a peptide hormone released from the Hypothalamus. It has a GPCR. It tonically inhibits prolactin (decrease DA, decrease PRL).

Question 10

What is CRH/CRF? What kind of hormone is it? Where is it from? What is it’s receptor? What does it do?

Answer 10

Corticotrophin Releasing Hormone/Factor. It is a peptide hormone which acts on A.P. to cause positive secretion of MSH and ACTH.

Question 11

What are the two parts of the pituitary gland?

Answer 11

Anterior and Posterior

Question 12

Where do the two parts of the Pituitary develop from?

Answer 12

Anterior - Oral Ectoderm

Posterior - Neuroectoderm

Question 13

What hormones are secreted by the posterior pituitary?

Answer 13

Oxytocin, Vasopressin

Question 14

What are the 5 important cell types in the anterior pituitary?

Answer 14

Gonadotroph, Lactotroph, Corticotroph, Thyrotroph, Somatotroph

Question 15

What are the main anterior pituitary hormones? (7)

Answer 15

LH, FSH, TSH, ACTH, MSH, GH, PRL

Question 16

What are LH and FSH? What controls their secretion? Where are they released from?

Answer 16

They are glycoprotein hormones produced by gonadotrophs. GnRH has positive effect on their secretion. They are released from A.P.

Question 17

What does LH do?

Answer 17

In male, LH stimulates testosterone secretion in the Leydig cells. In the female, with FSH it stimulates oestradiol synth, and the formation of CL.

Question 18

What does FSH do?

Answer 18

In male, it stimulates spermatogenesis. In the female, it stimulates follicle growth and oestrogen synth.

Question 19

What is GH? What controls it’s secretion? Where is it released from? What type of receptor does it use? What does it do?

Answer 19

Growth hormone is a peptide hormone released from the A.P, produced in somatotrophs. GHRH has positive effect on release, SST has negative effect on its release. It affects overall growth. It has a JAK-STAT receptor.

Question 20

How does IGF affect GH?

Answer 20

GH effects on liver and muscle are mediated by insulin like growth factors.

Question 21

What is TSH? What controls it’s secretion? Where is it released from? What type of receptor does it use? What does it do?

Answer 21

Thyroid stimulating hormone is a glycoprotein hormone released from A.P. TRH has a positive effect on secretion, but SST has a negative effect on its secretion. It stimulates T3/T4 production.

Question 22

What is Prolactin? What controls it’s secretion? Where is it released from? What type of receptor does it use? What does it do?

Answer 22

Prolactin is a peptide hormone released from the A.P. It uses a JAK-STAT receptor. TRH has a positive effect on secretion, Dopamine tonically inhibits it. It regulates lactation in primed mammary gland.

Question 23

What is ACTH? What controls it’s secretion? Where is it released from? What type of receptor does it use? What does it do?

Answer 23

Adrenocorticotrophin Hormone is released from the A.P by corticotrophs. It uses a GPCR (MC2-R). It causes the release of adrenal hormones e.g. cortisol, aldosterone, androgens.

Question 24

What is Agromegaly?

Answer 24

A disease caused by increase of GH. Often associated with lots of tumours.

Question 25

Where is Vasopressin made? Where is Vasopressin secreted?

Answer 25

Vasopressin is made in the Hypothalamus, and is secreted from the P.P.

Question 26

What is the POMC gene?

Answer 26

The POMC gene is a gene that is affect by CRH. It encodes many different substances e.g. ACTH and MSH.

Question 27

What is MHC? What controls it’s secretion? Where is it released from? What type of receptor does it use? What does it do?

Answer 27

Melanocyte stimulating hormone is a peptide hormone that is involved with the production of skin pigmentation. It uses GPCR (MC1-R). It is released by corticotrophs.