Endocrine Hypothalamus & Pituitary

Front 1

Which type of secretion (autocrine, paracrine or endocrine) are the following examples of? Inhibition of glucagon from pancreatic alpha cells by insulin from beta cells, and inhibition of insulin an dglucagon secretion by somatostatin secrtion from pancreatic delta cells?

Back 1

Paracrine

Front 2

a. What type of secretion causes the release of neuronal product directly into the blood stream? b. where does this type of secretion occur

Back 2

a) Neuroendocrine secretion b) adrenal medulla, hypothalamus and posterior pituitary

Front 3

What type of cellular communication occurs with thyroid hormones?

Back 3

these hormones, like steroid hormones, enter cells directly and interact with receptors at the nuclear level

Front 4

Which part of the pituitary arises from Rathke's pouch?

Back 4

Anterior pituitary

Front 5

What is Rathke's pouch?

Back 5

an evatination from the foregut of the region of the 3rd ventricle within the diencephalon

Front 6

Where are Adenohyophysis cells located and what do they do?

Back 6

these cells are in the anterior pituitary and produce hormones.

Front 7

What does the term neurohypophysis refer to?

Back 7

the posterior pituitary

Front 8

I which bony structure does the pituitary rest in ?

Back 8

sella turcica

Front 9

what is the sella turcica formed from?

Back 9

the spenoid wings at the base of the skull

Front 10

What is the median eminence?

Back 10

protruding base of the brain before entering the pituitary stock leading to the pituitary

Front 11

What is the function of the intermediate lobe (pars intermedia) in the pituitary?

Back 11

none

Front 12

Which 6 hormones does the anterior pituitary secrete?

Back 12

FSH, LH, TSH, ACTH, GH and PRL

Front 13

which two hormones does the posterior pituitary secrete? What type of secretion is this?

Back 13

Oxytocin and ADH… neuroendocrine

Front 14

Which cells types in the posterior pituitary produce oxytocin and ADH?

Back 14

supraoptic - ADH… paraventricular - Oxytocin

Front 15

What separate base of the brain from the pituitary?

Back 15

diaphragm sella

Front 16

What are the names of the vascular connections that carry blood from the median eminence to the down the stalk and into the pituitary?

Back 16

primary plexus and the portal hypophyseal vessels, which together make up the portal system leading to the anterior pituitary

Front 17

Between primary plexus and the portal hypophyseal vessels, which has fenestrated capilaries and lacks a blood brain barrier?

Back 17

primary plexus

Front 18

Name for major phsiologic functions critical to survival that are integrate by the hypothalamus? (hint: WET-B)

Back 18

Water balance, Energy balance, Temperature regulation, and Biological clock

Front 19

T/F: All specialized receptors for the control of temperature, Osmo, and Chemo are leading to the hypothalamus are located in the hypothalamus?

Back 19

False some are on the periphery

Front 20

What type of feedback controls cortisol production and how is this done?

Back 20

Negative feedback, where cortisol inhibits ACTH production in the pituitary

Front 21

Besides cortisol, what else controls ACTH secretion?

Back 21

1) the episodic dirunal rhythm and 2) increased stress

Front 22

Does estrogen have a negative or positive feedback effect on LH?

Back 22

both, depending on the stage of the reproductive cycle

Front 23

Where does feedback regulation of hormones occur, at the pituitary or the hypothalamus?

Back 23

both

Front 24

What type of molecular structure is LH? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 24

Glycoprotein

Front 25

What type of molecular structure is PRL? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 25

Single chain protein

Front 26

What type of molecular structure is GH? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 26

Single chain protein

Front 27

What type of molecular structure is TSH? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 27

glycoprotein (dimer)

Front 28

What type of molecular structure is ACTH? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 28

peptide arising from POMC

Front 29

What type of molecular structure is PRL? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 29

sinchain protein

Front 30

What type of molecular structure is FSH? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 30

Glycoprotein

Front 31

What type of molecular structure is 3-LPH (13-lipotopin)? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 31

Peptide arising from POMC

Front 32

What type of molecular structure is MSH (Melanocyte stimulating hormone)? Glycoprotein, Single chain protein, or a peptide arising from POMC?

Back 32

simple peptide arising from POMC

Front 33

Which type of cells produce the peptide (ranginng from 1-44 amino acids) hormones that are secreted in the hypothalamus and influence the pituitary?

Back 33

neurons

Front 34

Name the 5 hypothalamic hypophysiotropic hormones

Back 34

thyrotropin releasing hormone (TRH), Gonadotropin releasing hormone (GnRH), Corticotropin releasing hormone (CRH), Somatostatin (SRIF), Growth hormone releasing hormone (GHRH) and Dopamine

Front 35

Which are the three trophic hormones and what do they produce?

Back 35

Thyrotropin releasing hormone (TRH): TSH an PRL… b) Gonadotropin releasing hormone (GnRH): LH and FSH… c) Corticotropin releasing hormone (CRH): ACTH (which is incresed with sympathetic nervous system)

Front 36

What pituitary effect does the release of Somatostatin have?

Back 36

Inhibits GH and TSH release from the pituitary…

Front 37

Which hormone has a widespread distribution and actions including the GI tract and pancreas

Back 37

Somatostatin

Front 38

Which hypothalamus hormone releases GH from the pituitary?

Back 38

GHRH

Front 39

Which hypothalamic hormone stimulates PRL release and which inhibits it?

Back 39

Stimulates: TRH… Inhibits: Dopamine

Front 40

Which hypothalamic hormone inhibits both GH and TSH?

Back 40

Somatostatin

Front 41

Besides GH and TSH inhibition, what other function does somatostin have?

Back 41

Somatostatin produced in the pancreas inhibits insulin and glucagon by paracrine action

Front 42

Episodic function is often seen in which hypothalamic releasing hormone?

Back 42

GnRH

Front 43

What is the relationship between the struture of LH, FSH and TSH?

Back 43

They each share a common alpha chain, and differ in the beta chain

Front 44

In general, what do gonadotropin do?

Back 44

stimulate ovaries and testes

Front 45

What is the function of LH?

Back 45

stimulates hormone production

Front 46

What is the function of FSH?

Back 46

It regulates ovulation and spermatogenesis

Front 47

What is the function of TSH?

Back 47

stimulate the thyroid

Front 48

The is the direct function of GH?

Back 48

Stimulates IGF-1 productio in the liver and other tissues and has CHO metabolism

Front 49

What is the direct function of PRL?

Back 49

Stimulates lacation

Front 50

What is the direct function of ACTH?

Back 50

Stimulates the adrenal cortex, but it's not a direct effector

Front 51

What is the direct function of 3-LPH?

Back 51

Direct effector

Front 52

What is the direct function of Melanocyte stimulating hormone (MSH)?

Back 52

Direct effector of the mypothalamus

Front 53

T/F: MSH circulates systemically

Back 53

false: only in pituitary

Front 54

Characterize primary hypothyroidism

Back 54

absence of a functional thyroid

Front 55

Characterize secondary hypothyroidism

Back 55

lack of thyroid function due to TSH not being released by the pituitary

Front 56

Characterize tertiary hypothyroidism

Back 56

TSH is deficient secondary to TRH deficiency

Front 57

Besides primary, secondary and tertiary hypothyroidism, what can cause clinical manifestations of hypothyroidism?

Back 57

Thyroid hormone resistance due to mutation in the thyroid hormone receptors

Front 58

What type of hypothyroidism would low T4 in the presence of high TSH

Back 58

primary

Front 59

What type of hypothyroidism would low TSH in the presence of high TRH?

Back 59

secondary

Front 60

What type of hypothyroidism would low TSH in the presence of low TRH?

Back 60

tertiary

Front 61

Can GH stimulate growth in the absence of the target gland hormones, i.e., thyroid, gonads, adrenal cortex?

Back 61

No… but the target gland hormones cannot stimulate growth without GH

Front 62

What do GH , thyroid hormone, cortisol, sex steroids, and insulin have in common

Back 62

They are all growth hormones

Front 63

What must be provided to children with hypopituitarism?

Back 63

GH

Front 64

What are some symptoms of adults that have GH deficiency

Back 64

reduction in muscle mass and bone density as well as an increase in adiposity

Front 65

Which two hypothalamic hormones control GH?

Back 65

GHRH and somatostatin

Front 66

What does GH stimulate?

Back 66

Insulin like growth factor (IGF-1)

Front 67

What effect does excess IGF-1 have on GH

Back 67

negative feedback

Front 68

when is GH secretion highest?

Back 68

non REM sleep

Front 69

Besides GHRH and somatostatin, which other 2 ligands can inluence GH levels?

Back 69

TRH stimulates, and Ghrelin stimulates

Front 70

Where is Ghrelin produced?

Back 70

it is a peptide produced in the stomach

Front 71

Besides stimulating GH secretion, what effect does Ghrelin have?

Back 71

stimulates appetite, causing weight gain

Front 72

What effect do the following have on GH? Sleep, Exercise, Stress, hypoglycemia, Hyperglycemia, Amino Acids (Arginine), Estrogen, ß-adrenergic agonist (propranolol), and ∂-agonists (phentolamine)?

Back 72

Sleep: GH pulse at onset of sleep… Exercise: stimulate… Stress: increase secretion… hypoglycemia: increase secretion… hyperglycemia: inhibit secretion… Amino Acids: stimulate secretion… Estrogen: enhance GH action… ß-adrenergic agonist: inhibit secretion... ∂-adrenergic agonist:stimulate secretion.

Front 73

How do you test for GH deficiency?

Back 73

dynamically, because levels are low, i.e., 1) induce hypoglycemia w/insulin… 2) give ß-blocker + ∂-adrenergic agonist… 3) Give GHRH directly to test the function of the anterior pituitary directly… 4) check IGF-1, since low levels indicate GH deficiency. 5) check after exercise, 6) Give Gherlin

Front 74

How does hypoglycemia increase GH secretion?

Back 74

it's thought to decrease somatostatin and increase GHRH.

Front 75

How do you test the anterior pituitary directly for GH deficiency?

Back 75

Give GHRH

Front 76

What is somatomedin C synonymous with?

Back 76

IGF-1

Front 77

What happens to IGF-1 levels in nutrient deprived people?

Back 77

IGF-1 is decreased

Front 78

Is IGF-II regulated by GH?

Back 78

no

Front 79

What effect does GH have with respect to insulin?

Back 79

it counters insulin, thus raises blood glucose levels, especially in muscle and fat

Front 80

When GH deficiency exists, when is hypoglycemia more likely to exist?

Back 80

when other counterregulatory hormones deficiencies are present

Front 81

What effect does GH deficiency have on the adult?

Back 81

reduced lean, decreased bone density and increased fat

Front 82

If GH is present at birth, what is suspected?

Back 82

GHRH deletions in hypothalamus… autosomal recessive trait

Front 83

What is the most common cause of deficient GHRH?

Back 83

hypothalamic infiltrative disease or tumors

Front 84

What is the most common cause of GH deficiency?

Back 84

pituitary lesions, turmor… while, GH gene deletions are rare autosomal recessive disorders… GH receptor mutations have been characterized in GH deficiency

Front 85

A) What is primary cause of GH excess? B) what generally accompanies the rise in GH?

Back 85

A) pituitary adenoma producing GH… B) Prolactin production

Front 86

Besides pituitary tumors, what are some other causes of GH overproduction?

Back 86

tumors that produce GHRH found in the pancreas and hypothalamus (rare)

Front 87

What is the cause of acromegaly?

Back 87

overproduction of GH

Front 88

Why doesn't hyperglycemia suppress GH?

Back 88

because the somatotrophs in the pituitary are no profused by the hypphyseal pit-portal venus system

Front 89

What are the Rx for acromegaly?

Back 89

resection of tumor, radiation, somatostatin analog… or GH antagonists, which bind to only one receptor of the dimer receptor (Pegvisomant)

Front 90

What is prolactin tonically inhibited by?

Back 90

dopamin

Front 91

Why do prolactin levels rise during pregnancy?

Back 91

estrogen causes hyperplasia of lactotrophs.

Front 92

What inhibits lactation during pregnancy?

Back 92

high levels of estrogen and progesterone

Front 93

Why do PRL levels increase after pregnancy?

Back 93

rapid fall of estrogen and progesterone

Front 94

What maintains high levels of PRL after pregnancy?

Back 94

suckling

Front 95

What effects do you see with elevated PRL?

Back 95

galactorrhea and hypogonadotropic hypogonadism

Front 96

What are the functional causes of Hyerprolactinemia?

Back 96

hypothyroidism and renal failure

Front 97

What are the pharmacological causes of Hyerprolactinemia?

Back 97

Anti-dopaminergics

Front 98

What are the Tumoric causes of Hyerprolactinemia?

Back 98

Suprasella lesions, microprolactinomas, macdroprolactinomas,

Front 99

what are causes of diminished dopamine synthesis and release in the hypothalamus? And what the consequences?

Back 99

Tumors, arteriovenous malformation or inflammatory lesions, as well as drugs like ∂-methyldopa and reserpine which can deplete central dopamine store… consequences are Hyperprolactinemia

Front 100

What are 4 causes of hyperprolactinemia

Back 100

1) diminished synthesis and storage of dopamine in the hypothalamus… 2) interuption of the portal system… 3) Pituitary insensitivity due to drugs (antipsychotics, e.g., dopamine blockers)… 4) Prolactinomas (most common)

Front 101

What is the size limit for a microadenoma?

Back 101

< 1 cm

Front 102

What is the cause and presentation of Cushing's disease from pituitary tumors?

Back 102

small microadenoma --> ACTH excess

Front 103

What is the hormonal effect of hyperthyroidism from pituitary tumors?

Back 103

TSH excess, very rare

Front 104

T/F FSH secreting tumors from pituitary tumors are rare

Back 104

false, they are common silent clinically

Front 105

Name 7 causes of hypopituitarism.

Back 105

1. Pituitary tumors, 2. parapituitary tumors, 3. Post partum infarction (Sheehan's syndrome), 4. Infiltrations (sarcoidosis, histiocytosis, hemochromatosis), 5. Hypophysitis, 6. Infections, 7. Trauma.

Front 106

What is Sheehan's syndrome and what causes it?

Back 106

Hypopituitarism in women who experienced a difficult birth, who suffer post partum infarction of the pituitary… attributed the vulnerability of the pituitary to a drop in blood pressure caused by blood loss

Front 107

What is hypophysitis?

Back 107

hypopituitarism caused by a rare autoimmune disase of the pituitary

Front 108

Give 2 infections that can cause hypopituitarism

Back 108

tuberculosis and syphilis

Front 109

what is idiopathic hypopituitarism thought to be caused by?

Back 109

absent hypothalamic control of the anterior pituitary

Front 110

Which hormonal deficiency is seen in the Amish population?

Back 110

GH deficiency

Front 111

What Kallman's syndrome?

Back 111

the association of LH deficiency and anosmia (loss of sense of smell)

Front 112

What do low levels of target organ hormones in the absence of elevated pituitary hormones indicate?

Back 112

Hypopituitarism… because the pituitary should be compensating

Front 113

Besides looking for ow levels of target organ hormones in the absence of elevated pituitary hormones, how can you diagnose hypopituitarism? Give 4 examples.

Back 113

stimulate hormone secretion to see if there are pituitary reserves present: 1) Insulin induced hypoglycemia --> should stimulate GH and ACTH… 2) TRH should increase TSH… 3) GHRH should stimulate GH… 4) GnRH should stimulate FSH and LH

Front 114

What is the order of loss of pituitary hormones in hypopituitarism?

Back 114

GH… LH, FSH… TSH, ACTH

Front 115

How do ADH and Oxytocin begin?

Back 115

as prohormones: Neurophysin, which chaperones ADH and Oxytocin through the axons from the hypothalamus to the pituitary

Front 116

Are ADH deficiencies seen with pituitary lesions? Why or why not?

Back 116

No, because ADH is synthesized in the hypothalamus and can be secreted as long as the axon is long enough.

Front 117

Where are ADH deficiencies seen?

Back 117

With hypothalamus lesions

Front 118

What is the cause of the rare Familial ADH deficiency?

Back 118

mutation in the neurophysin portion of the gene

Front 119

What function does Oxytocin serve?

Back 119

contraction of mammary ducts and mild ejection (secretion caused by suckling)… not… causes contraction, but it's not required for this.

Front 120

What effect does ADH have?

Back 120

1) ADH augments CRH effects on ACTH, 2) ADH is responsible for free water readsoption by the kidney and 3) ADH is a vasoconstrictor.

Front 121

When is ADH critical?

Back 121

major injury

Front 122

a)What do the following ADH receptors mediate, b) what effect do they have and c) where are they found? V1, V2, V3

Back 122

V1: Phospholipid mediator, vasoconstriction, vascular smooth muscle… V2: cAMP, increase H2O permeability through aquaporin 2, renal collecting tubule… V3: Phospholipid mediator, ACTH secretion, Anterior pituitary

Front 123

Characterize ADH and water regulation

Back 123

Increasing plasma osmolarity is communicated to the hypothalamus from baroreceptors that measure volume in the atria and great vessels--> ADH secretion & increased thirst,

Front 124

What is central diabetes insipidus?

Back 124

absence of ADH

Front 125

What is Nephrogenic Diabetes Insipidus?

Back 125

ADH action is impaired

Front 126

Name 8 causes of central diabetes insipidus?

Back 126

1. Pituitary tumor, 2) parapituitary tumor, 3) infiltrative diseases of the hypothalamus (sarcoids), 4) Metastic dises oto the hypothalamus, 5) Basal skull fractures, 6) Idiopathic, 7) Familial, 8) Vasopressinase (produced in the placenta and cleaves ADH) treated with DDAVP

Front 127

See pages 49 and 50 for graph interpretation