Endocrine- Hypothalamus and Pituitary

Question 1

Hypophysis

Answer 1

AKA pituitary

hypophysectomy-removal of pituitary

Question 2

Parts of pituitary

Answer 2

Adenopophysis

• pars intermedia
• pars tuberalis
• pars distalis (90% of anterior pituitary)

Neurohypophysis

• pars nervosa (posterior pituitary)
• median eminence (base of hypothalmus)
• infundibular stalk

Question 3

Part of pituitary where Cushing’s disease problem occurs

Answer 3

Pars intermedia
(present in non-primates)

Question 4

Where does pituitary sit

Answer 4

Sphenoid bone

Question 5

Hormones secreted by anterior pituitary 6

Answer 5

GH
FSH
LH
ACTH
TSH
Prolactin

Question 6

GH

• secreted by
• made by
• function

Answer 6

• Anterior pituitary
• Somaotrophs
• Growth and metabolism

Question 7

ACTH

• secreted by
• made by
• function

Answer 7

• Anterior pituitary
• Corticotrophs
• stimulates cortisol secretion from adrenal

Question 8

TSH

• secreted by
• made by
• function

Answer 8

• anterior pituitary
• thyrotrophs
• stimulates T4 and T3 production

Question 9

LH

• secreted by
• made by
• function

Answer 9

• Anterior pituitary
• gonadotrophs
• stimulates testerosterone secretion and ovulation

Question 10

FSH

• secreted by
• made by
• function

Answer 10

• anterior pituitary
• gonadotrophs
• regulates follicular growth in females

Question 11

Prolactin

• secreted by
• made by
• function

Answer 11

• anterior pituitary
• lactotrophs
• mammary development

Question 12

What is the primary blood supply to anterior pituitary?

Answer 12

hypothalamic-hypophysial portal system

Question 13

Where does hypothalamic-hypophysial portal system originate

Answer 13

median eminence

Question 14

Hormones released from hypothalamus reach anterior pituitary how?

Answer 14

Hormones like AVP and Oxy reach anterior pituitary via hypothalamic-hypophysial portal system to allow specific delivery at high concentrations.

Question 15

Hypothalamic hormones that regulate anterior pituitary 6

Answer 15

TRH
CRH
GHRH
Somatostatin
GnRH
Dopamine

Question 16

TRH

• made in
• function

Answer 16

Hypothalamic nuclei

Stimulates TSH release

Question 17

CRH

• made in
• function

Answer 17

Hypothalamic nuclie

Stimulates ACTH release

Question 18

GHRH

• made in
• function

Answer 18

Hypothalamic nuclei

Stimulates GH release

Question 19

Somatostatin

• made in
• function

Answer 19

Hypothalamic nuclei

Inhibits GH

Question 20

Dopamine

• made in
• function

Answer 20

Hypothalamic nuclei

Inhibits prolactin

Question 21

How can you have over secretion of prolactin? What effect would you see?

Answer 21

Functional tumor of lactotrophs or damage to pituitary stalk (loss of dopamine)

-Upset in reproductive cycle

Question 22

Cushing’s disease in dog treatment

Answer 22

#1 spp to get Cushings
Take out entire pituitary BUT this can cause diabetes insipidus-PUPD- due to lack of vasopressin

-May need to give exogenous ADH (vasopressoin(

Question 23

Is GH species specigic?

Answer 23

Y

Question 24

What does GH receptor work under

Answer 24

Jak/Stat pathway (tyrosine kinase)

Question 25

How much GH is bound to carrier protein?

Answer 25

1/2

Question 26

How should you measure GH from patient?

Answer 26

Take multiple samples during the day because GH is released in sporadic bursts. More bursts at night. Or give GHRH to produce more GH to be collected and analyzed.

Question 27

GH release control is at the level of

Answer 27

Somatotrophs

Question 28

When do you see more GH in circulation?

Answer 28

``` Sleeping Starvation Hypoglycemia Low FA Exercise, trauma Increase in AA in blood ```

Question 29

What are direct effects of GH?

Answer 29

Increase in lean mass (decrease adipose tissue, increase muscle), preserve glucose and proteins and use up fat

Question 30

Indirect effects of GH

Answer 30

``` Increase chondrocytes (bone growth) Increase cell division of muscles and proteins -->Decrease protein breakdown ```

Question 31

Indirect effects of GH are mainly due to

Answer 31

Insulin like growth factors - IGF-1=adults - IGF-2=fetus

Question 32

Major source of IGF

Answer 32

Liver | "hypothalamic-pituitary-liver axis"

Question 33

What does IGF bind to?

Answer 33

IGFBP which binds to acid labile subunits ALS

Question 34

What does GH stimulate in liver

Answer 34

Production of IGF, IGFBP, ALS

Question 35

GH disorders-deficiency

Answer 35

``` Dwarfism Laron dwarfs (GH receptor defect) African Pigmy (no IGF-1 increase at puberty) ```

Question 36

GH disorders-XS

Answer 36

Gigantism (before puberty) | Acromegaly (after puberty)

Question 37

GH disorders in dogs

Answer 37

Xs progesterone

Question 38

GH disorders in cats

Answer 38

GH secreting pituitary tumor - Increases glucose and insulin - Makes it difficult to control diabetes - Dx=measure IGF-1

Question 39

Bovine Somatotropin

Answer 39

bST | -Used to increase milk production by increasing IGFs.

Question 40

Posterior pituitary hormones

Answer 40

Derive from magnocellular neurons, neurophysins - ADH or AVP - Oxytocin

Question 41

ADH or AVP - from - n - fxn

Answer 41

Magnocellular neurons-posterior pituitary supraoptic n Water conservation:main target kidney. -->In presence of ADH, renal CD cells become permeable to water

Question 42

Oxytocin - from - n - fxn

Answer 42

Magnocellular neurons paraventricular n Role in parturition (expulsion of fetus) Milk-let down (stimulates myoepithelial cells in mammary gland) Controls corpus luteum (secretes progesterone)

Question 43

Function of osmolreceptors

Answer 43

Detect shrinking of ADH neurons due to high osmolaity (high salt). ADH levels will increase before we feel thirsty

Question 44

What does nueorphysin complex help?

Answer 44

Helps AVP travel down axon from hypothalamus to pituitary

Question 45

Major targets of ADH

Answer 45

cortical and medullary CD

Question 46

Decrease ADH

Answer 46

Increase fluid Dilute/high urine volume Hypotonic environment

Question 47

Increase ADH

Answer 47

Decrease fluid | More concentrated urine

Question 48

How do you increase CM permeability in cortical/medullary CD?

Answer 48

Increase cAMP to get an increase in PKA | Increases aquaporin 2 channels in CM to allow water in

Question 49

What do you see with true diabetes insipidus

Answer 49

Dilute urine in high volume not due to defect w/kidney

Question 50

Central diabetes insipidus

Answer 50

Due to lack of ADH

Question 51

Nephrogenic diabetes insipidus

Answer 51

Due to insensitivity to ADH action in kidney | mutation in ADH receptor gene or aquaporin 2 gene

Question 52

Not true diabetes insipidus causes that can interfere with action of ADH

Answer 52

Increased levels of glucocorticoids Infection in kidney Hypercalcemia Pyometra

Question 53

Rare cause of PUPD

Answer 53

True diabetes insipidus | -central or nephrogenic

Question 54

Common cause of PUPD

Answer 54

Kidney disease | Metabolic or endocrine disease