Lecture 60-Pituitary Hormones

Question 1

What is growth hormone (somatotropin) secreted by?

Answer 1

Somatotrophs

Question 2

Stimulators of growth hormones? (6)

Answer 2

GHRH
Decreased glucose
Decreased FFA
Increased AA
Hypoglycemia/fasting/starvation
Puberty (estrogen/testosterone)

Question 3

What are stimulators of growth hormones that play a role in nutrient regulation?

Answer 3

Decreased glucose
Decreased FFA
Increased AA
Hypoglycemia/fasting/starvation

Question 4

What are inhibitors of growth hormones?

Answer 4

Somatostatin
Increased glucose, FFA
GH
Obesity
Somatomedins (IGF)

Question 5

What stimulates somatostatin to be released from hypothalamus?

Answer 5

Somatomedins (IGF)

Question 6

Where are the metabolic actions of growth hormones?

Answer 6

Liver, muscle, adipose, bone

Question 7

What are five things that growth hormones affect?

Answer 7

Linear growth, protein synthesis, organ growth, carbohydrate, and lipid metabolism

Question 8

Direct anabolic actions -> increased ______ absorption from _____, ____ reabsorption from _____, ______ synthesis in the _____.

Answer 8

Ca Absorption from gut
P reabsoprtion from kidney
Protein synthesis in liver

Question 9

Where are IGF-2 (somatomedin A) made?

Answer 9

Made in the liver

Question 10

What affect do indirect anabolic actions via somatomeids have?

Answer 10

Increase lean muscle mass, linear bone growth, organ size/function

Question 11

What are the two direct catabolic effects of growth hormone?

Answer 11

1. Increased gluconeogenesis in liver
2. Increase lipolysis in adipose tissue

Question 12

By increasing lipolysis in adipose tissue what is released into the blood? What formation is increased?

Answer 12

-Release of FFA into blood
*FFA is used for energy

-increased formation of ketones
*a lot of ketones lead to metabolic acidosis

Question 13

What does a deficiency of growth hormone result in?

Answer 13

Dwarfism

Question 14

What does excessive growth hormone secretion result in?

Answer 14

Acromegaly

Question 15

What does progesterone do to insulin and growth hormone?

Answer 15

Progesterone antagonizes insulin and stimulates growth hormone

Insulin resistance and possible ketoacidosis

Question 16

Increase growth hormone -> insulin _____ -> _______ketoacidosis

Answer 16

Insulin Resistance
Diabetic ketoacidosis

Question 17

What are the (2) hormones released from posterior pituitary?

Answer 17

1. Antidiuretic hormone
2. Oxytocin

Question 18

What is ADH synthesized by and where?

Answer 18

Synthesized by neurons in supraoptic nuclei of hypothalamus

Question 19

What is oxytocin synthesized by and where?

Answer 19

Synthesized primarily by neurons in paracentricular nuclei of hypothalamus

Question 20

ADH peptide precursor = __________________

Answer 20

Prepropressophysin

Question 21

Oxytocin peptide precursor = ________________

Answer 21

Prepro-oxyphysin

Question 22

What are stimulators of ADH secretion?

Answer 22

Increased plasma osmolarity
Decreased blood volume (hypovolemia)
Decreased blood pressure
Pain
Nausea
Hypoglycemia
Nicotine, opiates

Question 23

What do all the stimulators of ADH have in common?

Answer 23

They all reabsorb water

(Stimulators: increased plasma osmolarity, decreased blood volume (increased plasma osmolarity, decreased blood pressure, pain, nausea, hypoglycemia, nicotine, opiates)

Question 24

What are the inhibitors of ADH secretion?

Answer 24

Decreased plasma osmolarity, increased blood volume (hypervolemia), increased blood pressure, ethanol, glucocorticoids

Question 25

What do all the inhibitors of ADH secretion have in common?

Answer 25

Don’t reabsorb water—excreted in urine (Decreased plasma osmolarity, increased blood volume (hypervolemia), increased blood pressure, ethanol, glucocorticoids)

Question 26

What part of the nephron is permeable to water?

Answer 26

Distal consulted tubule Collecting duct

Question 27

When can water be reabsorbed into blood?

Answer 27

Under the influence of ADH

Question 28

What are the two major actions of ADH?

Answer 28

Kidney and vascular smooth muscle

Question 29

ADH receptor = ______ receptor

Answer 29

V2

Question 30

What two things does the ADH receptor use?

Answer 30

Adenylyl Cyclades and cAMP

Question 31

What is inserted into the membrane of principal cells in the kidney?

Answer 31

Aquaporin 2

Question 32

What type of receptor does vascular smooth muscle contraction use?

Answer 32

Uses V1 receptor

Question 33

What is the syndrome of inappropriate ADH secretion?

Answer 33

-excess ADH released from posterior pituitary -hypervolemia and hyponatremia -urine is very concentration

Question 34

What is peripheral or nephrogenic diabetes insipidus?

Answer 34

-posterior pituitary normal but principals cells in collecting duct unresponsive to ADH -defective V2 receptor -dilute urine, concentration body fluids -circulating ADH increases (high)

Question 35

What is central diabetes insipidus?

Answer 35

-lack of ADH secretion -can be at hypothalamus or pituitary -circulating levels of ADH low -can’t concentrate urine, large volume dilute urine -plasma osmolarity increased