Endocrine Control Of Growth

Front 1

Review:

How does plasma insulin and glucagon change during and after meals?

Back 1

Front 2

1. Glucose can be used by all _________, BUT
--limited amount of __________ glucose (about 1 hour’s worth)

2. Glycogen stores: more, BUT only enough for about________ day’s fuel requirements; 100 g stored in______ and 200 g in our ______.

3. ________ is most efficient energy storage form (enough for about 40 day’s fasting) 250 gm / day; a non-obese, 70 kg man has about 10,000 g fat stored, mostly in AT, some in muscle and liver

4. While many tissues can oxidize carbos, fat, and AAs for energy, some tissues MUST have ___________: nerves (aka “brain”), RBC, WBC, renal tubules.
-- nerves use about 150 gm________/day
-- others use about 50 gm _________
5. Homeostatic regulation is provided by the __________ and __________;
--however, intracellular biochemical regulators also are important, esp. via the glucose-FA cycle, also [acetyl CoA], [Gluc- 6-P].

Back 2

1. Glucose can be used by all tissues, BUT
--limited amount of circulating glucose (about 1 hour’s worth)

2. Glycogen stores: more, BUT only enough for about ½ day’s fuel requirements; 100 g stored in liver and 200 g in our muscles.

3. Fat is most efficient energy storage form (enough for about 40 day’s fasting) 250 gm / day; a non-obese, 70 kg man has about 10,000 g fat stored, mostly in AT, some in muscle and liver

4. While many tissues can oxidize carbos, fat, and AAs for energy, some tissues MUST have glucose: nerves (aka “brain”), RBC, WBC, renal tubules.
-- nerves use about 150 gm glucose/day
-- others use about 50 gm glucose/day

5. Homeostatic regulation is provided by the hormones and ANS;
--however, intracellular biochemical regulators also are important, esp. via the glucose-FA cycle, also [acetyl CoA], [Gluc- 6-P].

Front 3

Muscle is about ________ of body mass and at rest, uses about _________of O2 consumed; much more with use. So affecting muscle metabolism has a big effect.
Fortunately, muscle “loves” to use ______ and _________for energy production,
and this in itself spares glucose and AAs from oxidation in that tissue.

Hepatic ________ is the most immediate source of glucose most of the time. Liver (& kidney) _________ mainly replenish glycogen stores.

--In exercise, muscle _________ also is used; when depleted: it fails to work

8. __________ acts powerfully to inhibit hepatic glucose output and increase peripheral glucose _________ and _________ (for energy, muscle glycogen, TAG in Adipose Tissue).

9. The liver is more responsive to ________ than are muscle and fat; moreover, it is exposed to higher concentrations of ________ than are all other non-pancreatic tissues.

Back 3

Muscle is about 50% of body mass and at rest, uses about 30% of O2 consumed; much more with use. So affecting muscle metabolism has a big effect.
Fortunately, muscle “loves” to use FA and KBs for energy production,
and this in itself spares glucose and AAs from oxidation in that tissue.

Hepatic glycogen is the most immediate source of glucose most of the time. Liver (& kidney) gluconeogenesis mainly replenish glycogen stores.

--In exercise, muscle glycogen also is used; when depleted: it fails to work

8. Insulin acts powerfully to inhibit hepatic glucose output and increase peripheral glucose uptake and utilization (for energy, muscle glycogen, TAG in Adipose Tissue).

9. The liver is more responsive to insulin than are muscle and fat; moreover, it is exposed to higher concentrations of insulin than are all other non-pancreatic tissues.

Front 4

What are the body's objectives for during and after a meal?

1) Fill _________stores (from carbos)

2) Don't spill much ________ in urine

3) Utilize ingested __________ for energy

4) Package _________:

carbos & fats as _________ [in AT (adipose tissue)]

AAs as ___________

Back 4

1) Fill glycogen stores (from carbos)

2) Don't spill much glucose in urine

3) Utilize ingested carbos & fat for energy

4) Package excess:

carbos & fats as TAG [in AT (adipose tissue)]

AAs as protein

Front 5

What is the glucose-fatty acid cycle?

Draw using the following:

Fatty acids

TG

FFA

CO2

Glucose-6-P

GLucose

Adipocyte

Blood

Myocyte

Back 5

Front 6

Between meals (post-absorptive phase)

Objectives

1) Keep _________ ~ constant for CNS, etc.

2) _____ Glucose utilization (except CNS, etc)

3) Keep some _______ reserves (for “quick use")

4) Burn ______ for energy (FA, KB)

5) Utilize "sparable" _________

(& glycerol, lactate, etc.) for gluconeogenesis

Back 6

Between meals: Post-absorptive phase

Objectives

1) Keep glucose ~ constant for CNS, etc.

2) Glucose utilization (except CNS, etc)

3) Keep some glycogen reserves (for “quick use")

4) Burn fats for energy (FA, KB)

5) Utilize "sparable" proteins ( AAs)

(& glycerol, lactate, etc.) for gluconeogenesis

Front 7

What are the two origins of fuel? Where do they go? What are the three components of fuel consumption?

Back 7

Front 8

Major Processes
Carbohydrates:

_____ glucose uptake & utlization
_____glycolysis
_____ gluconeogenesis
small ______glycogenolysis
small ______glycogenesis
only small ______ glycogen stores
Fats:

______lipogenesis
______lipolysis ==> _____ FFA

_____fat stores
______ketogenesis
Proteins:

_____PS
_____PD
_____protein stores, especially in _____ and ______ tissues (from "sparable proteins")

Back 8

Front 9

Fill in the time courses:

Short acting vs. Long acting

Onset of actions (rapid, delayed)

Duration (brief, prolonged)

Examples of each

Primary mechanisms:

Back 9

Front 10

During fasting:

How does glucose change days 1-5?

What about insulin? Glucagon?

Cortisol levels?

Sympathetic activity levels?

GH levels?

T3 levels?

Think about the effects of each on metabolism.

Back 10

Front 11

What are the three hormones that do no change between feeding and fasting?

Back 11

Cortisol, GH, T3

Front 12

How does glucagon, E and NE, and insulin change from "during and after a meal" to " between meals"

Back 12

Front 13

Which hormones promote glucose production in the liver?

Which inhibits glucose production in the liver?

Which hormones inhibit glucose consumption in muscle and adipose tissue?

Which hormone promotes glucose consumption (muscle and adipose tissue)?

Back 13

Front 14

Glucagon, epinephrine, and cortisol act ___________ on plasma glucose concentration.

Back 14

Synergistically.

Front 15

Draw the pathways for hormonal effects on FFA production.

Insulin, glucose, a-glycerol, fatty acids, triglyceride, hormone sensitive lipase, protein kinase A, cyclic AMP, ATP, insulin, NE and E, cortisol, GH

Back 15

Front 16

What is the time course for lipolysis stimulated by catecholamines as compared to GH (which is faster and is much more potent)?

Back 16

Front 17

Glucocorticoids promote ______ by complimentary mechanisms:

A. In the LIVER:
1. They have previously induced ________ of KEY gluconeogenic and amino-acid-metabolizing enzymes,
2. They _________hepatic responsiveness to glucagon re: enhancing amino acid uptake into the liver.
3. Any more GC will further ________ synthesis of gluconeogenic enzymes; it may also __________ their activities.
B. PERIPHERALLY, GC actions provide more __________ for the liver:
1. Esp. in MUSCLE (but also others, e.g., lymphoid tissue)
__________ AA release -from net protein breakdown
( i.e., PD > PS)
(GC mainly _______ PS, but @ v. high concs., GC also _________ PD)
2. In adipose tissue.
________ glycerol release; glycerol ______ liver ______ glucose
GC (acting with GH & T3) permits an _____ in Epi and NE to ______ lipolysis: TAG ==> FA + glycerol

Back 17

Front 18

Enzymes Altered by Glucagon:

A. Via __ cAMP and __ protein kinase A:

1. __ phosphorylase activity

2. __ glycogen synthetase activity

3. __ formation of F-2,6-BP:

__ PFK activity (__ glycolysis)

__ F-1,6-BPase activity (__ gluconeogenesis)

4. __ PK activity (___PEP è pyr ... & __ AcCoA)

5. __ AcCoA carboxylase activity

(__ AcCoA __ malonyl CoA ... __ LCFA synth. and ...__ LCFA b-oxidation, since mal-GoA inhibits CPT-1, and thus inhibits FA b-oxidation)

B. Uncertain mechanisms

1. __ PEP carboxykinase synthesis

2. sl. __ Pyruvate carboxylase

Back 18

Front 19

What happens to plasma glucose during exercise? FFA? Muscle glycogen? in terms of contribution to oxygen uptake

Back 19

Front 20

How does insulin, E, NE, glucagon, cortisol, GH change during exercise?

Back 20

Front 21

What happens when you give exogenous insulin?

Which three hormones then increase around 70?

Which hormone increases around 60?

When do you start to get symptoms of hypoglycemia?

What does the liver do around 50?

At what level does cognition start to decrease?

Back 21

Your own insulin secretion shuts off.

Front 22

What are the effects of IGF-1 on GH Rx on growth velocity?

Back 22

Front 23

What are the effects of GH medication? Retention of what elements?

Back 23

Front 24

What is the effect of T3 on growth hormone?

Back 24

Increases number and size

Secretes more

Increase responsiveness of target cells to growth hormone

Front 25

What is the effect of GCs on GH?

Back 25

Decrease growth hormone

Cortisone in higher amounts => decrease in growth rate.

Front 26

What is needed for GH to stimulate growth?

Back 26

Insulin

Reduction in insulin => decreased growth rate even with GH

Front 27

What would happen to growth rate if you have hyperthyroidism?

Back 27

Decrease to to hyper metabolic effects => decreased calories available for growth

Front 28

What is the major time to secrete growth hormone?

Back 28

Secretory pattern = ultraridian (episodic)

Major secretion at night associated with deep sleep

Front 29

Which sleep stages if GH secretion associated with?

What are cortisol levels during this time?

Back 29

Stages III and IV

Front 30

What age range has the highest levels of GH?

Back 30

Front 31

What are range has the highest levels of IGH-1?

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Front 32

Which hormones also increase GH secretion?

Back 32

Sex

Front 33

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Front 34

Does insulin-induced hypoglycemia stimulate GH secretion?

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Front 35

What might be a more useful measure of a person's GH secretory status?

Back 35

IGF-1 levels