1. Hormonal control and responses

2. Types of Hormones Amino acid derivatives Protein Steroids
epinephrine, serotonin, melotonin
Protein
insulin, parathyroid hormone, growth hormone
Steroids
derived from cholesterol
sex hormones, mineralocorticoids, prostaglandins

3. Hormone-receptor interaction
Some hormones circulate to all tissues, but only act on some
receptor must be present for effect to occur
eg thyroid stimulating hormone only exerts an effect on the thyroid
conversely some hormones work on virtually all tissues (insulin)

4. Blood Hormone Concentration
the effect of a hormone related to concentration in blood (to a point)
Concentration affected by 4 factors
rate of hormone secretion
rate of metabolism or excretion
transport proteins
plasma volume (affected by exercise)

5. Control of Hormone Secretion
Rate of insulin secretion from the pancreas is dependent on:
Magnitude of input
Stimulatory vs. inhibitory

6. Factors That Influence the Secretion of Hormones

7. Mechanisms of Hormone Action
alteration of membrane transport (insulin)
stimulation of DNA synthesis (testosterone, estrogen)
activation of “second messengers”
hormone doesn’t enter the cell

8. Relationship of Hypothalamus, Pituitary and Target Glands

9. The Hypothalamus is the “Master Gland”
the hypothalamus controls the pituitary in two ways
the hypothalamus can release “releasing hormones”
releasing hormones act on anterior pituitary (TSH, ACTH, GH)
neurons originating in the hypothalamus act on posterior pituitary (ADH)

10. Positive and Negative Input to the Hypothalamus (Growth Hormone)

11. Growth Hormone uptake of amino acids and protein synthesis
opposes insulin
reduces use of plasma glucose
increases gluconeogenesis
mobilizes FFA

12. Antidiuretic Hormone (ADH)
causes resorbtion of H2O to maintain fluid
stimulated by two factors
high plasma osmolality (sweating)
low plasma volume (loss of blood, exercise)

13. Intensity vs. Plasma ADH

14. The Adrenal Glands Medulla Cortex
secretes epinephrine (E) and norepinephrine (NE)
Cortex
secretes mineralocorticoids, glucocorticoids

15. Response to Catecholamines: Role of Receptor Type
Effect of E/NE
Membrane-bound enzyme
Intracellular mediator
Effects on Various Tissues 1
E=NE
Adenylate cyclase
 cAMP
 Heart rate
 Glycogenolysis
 Lipolysis 2
E>>>NE
 Bronchodilation
 Vasodilation 1
ENE
Phospholipase C
 Ca++
 Phosphodiesterase
 Vasoconstriction 2
cAMP
Opposes action of 1 & 2 receptors

17. Aldosterone (Mineralocorticoid)
regulates K+ and Na+ concentrations
controls resorbtion in the kidney
involved in thirst response

18. Intensity vs. Mineralocorticoid Response

19. Cortisol Actions Involved in adaptation response to stress (exercise)
promotes breakdown of tissue protein (inhibits protein synthesis)
mobilizes FFA from adipose
stimulates gluconeogenesis
blocks entry of glucose into tissues (increases fat utilization)
Involved in adaptation response to stress (exercise)

20. Control of Cortisol Secretion

21. Pancreas Insulin Glucagon aids in transport of glucose into cells
stimulated when blood sugar increases (storage of glucose, amino acids and fat)
inhibited during exercise
Glucagon
opposite effect of insulin
stimulated by low blood glucose
mobilizes glucose and fatty acids

22. Sex Hormones testosterone
elevated during short-term high intensity exercise
levels typically lower in endurance trained individuals

23. Estrogen promotes higher levels of fat metabolism ?
chronic endurance training may suppress E2 (amenorrhea)

24. Muscle Glycogen Utilization
glycogen metabolism controlled by epinephrine (cAMP) and intracellular Ca++ (calmodulin) from sarcoplasmic reticulum
epinephrine increases rapidly with intense exercise
adrenergic blockade
glycogen depleted only in exercising muscles
Ca++ faster than cAMP and more specific

25. Blood Glucose Homeostasis During Exercise
mobilization of glucose from liver glycogen stores
mobilization of plasma FFA from adipose tissue to spare plasma glucose
synthesis of new glucose in the liver (gluconeogenesis) from AA, La, and glycerol
blocking of glucose entry into cells to force the substitution of FFA as a fuel

26. Slow Acting Hormones Thyroxine Cortisol GH
allows other hormones (eg epinephrine) to exert effect
Cortisol GH

27. Cortisol and Maintenance of Plasma Glucose

28. At low intensity, cortisol decreases- at high intensity it increases

29. Growth Hormone Effects During Exercise

30. Growth Hormone During Exercise
Combine amino acids and glycerol to make glucose in the liver
Breaks down triglycerides (fat) in the adipose tissue to make FFA available
Blocks entry of glucose into the cell
All of these go to maintain blood glucose

31. Plasma GH Response vs. Intensity

32. GH Response in Runners vs. Controls (Runners have improved response)

33. Fast Acting Hormones catecholamines (epinephrine and norepinephrine)
N primarily neurotransmitter at synapse
E primarily plasma hormone
insulin
glucagon

34. Effects of Catecholamines during Exercise

35. Catecholamines (adrenergic) During Exercise
Break down glycogen in liver to free glucose available
Break down triglycerides in the adipose tissue to make FFA available
Block entry of glucose into the cell

36. Catecholamine Response during Prolonged Exercise

37. Insulin (storage) vs. Glucagon (mobilization)

38. Insulin Levels Reduced during Moderate to Intense Exercise

39. Endurance Training Attenuates Insulin Response at Given Workload

40. Reduced Glucagon Response after Endurance Training

41. Take home…
Almost all of the hormonal responses will be attenuated with endurance training
Exception-growth hormone

42. Glucagon Response Reduced after Endurance Training Because…
increased utilization of FFA as fuel substrate
decreased reliance on plasma glucose
therefore decreased reliance on liver glycogen

43. Remember
-adrenergic… inhibition
-adrenergic… excitation

44. Adrenergic Control of Pancreatic Hormones

45. Effect of Increased Sympathetic Activity on Fuel Utilization

46. Glucose Uptake by Cells can Increase 7-25 Fold During Exercise. How?
increased blood flow to exercising tissues
increased metabolism causes gradient (diabetics)
increased # s of glucose transporter at membrane (diabetics)

47. General Hormonal Responses to Graded or Prolonged Exercise

48. Lactic Acid Inhibits FFA Release from Adipose Tissue (Means?)