Chapter Four: Endocrine Responses to Resistance Exercise Flashcards
1
Q
General Adaption Syndrome
A
- Response pattern described by Hans Selye to describe bodily adaptions to stressors
- Applicable to strength and conditioning due to the need to understand the process of adaption following a stressor to the body like with resistance training
2
Q
General Adaption Syndrome: Adaption
A
- It is important to understand the process of training adaption which is the process by which there is an increase in resistance to a stressor
3
Q
Synthesis, storage, and secretion of Hormones: Hormones
A
- Chemical messengers or signal molecules that are synthesized, stored, and released into the blood
4
Q
Synthesis, storage, and secretion of Hormones: Endocrine glands
A
- Body structures specialized for the production of hormones
5
Q
Synthesis, storage, and secretion of Hormones: Neuroendocrinology
A
- Refers to the study of interactions between the nervous system and the endocrine system
6
Q
Synthesis, storage, and secretion of Hormones: Intacrine and autocrine secretion
A
- Intacrine and autocrine secretion involves the process by which a cell releases a hormone to act on the cell itself via binding to intracellular and membrane receptors.
- May also be stimulated via external stimulus
- Secreted hormone does not enter the blood stream
7
Q
Synthesis, storage, and secretion of Hormones: Paracrine secretion
A
- Release of a hormone to interact with adjacent cells without moving into blood circulation.
8
Q
Synthesis, storage, and secretion of Hormones: Binding Proteins
A
- Proteins that bind to hormones and transport them in the blood to target destinations
- Protect the hormone from degradation
- When the hormone is bound it is not able to achieve its specific function. Must unbind itself to interact with target tissue
- Some binding proteins can interact with tissues while some are not able to
9
Q
Muscle as the Target for Hormone Interactions
A
- Hormones play an important role in the process of muscle building and recovery
- Hormones help to signal for protein synthesis and degradation and the laying of muscle cells
10
Q
Muscle as the Target for Hormone Interactions: Anabolic hormones
A
- Hormones that promote tissue building and block the degradation of muscle and proteins including:
- Insulin
- Insulin like growth factor
- Testosterone
- Growth hormone
11
Q
Muscle as the Target for Hormone Interactions: Thyroid Hormone
A
- Allows for the actions of other hormones to take place
12
Q
Muscle as the Target for Hormone Interactions: Catabolic Hormones
A
- Hormones that degrade cells and cell proteins including:
- Cortisol
- Progesterone
13
Q
Muscle as the Target for Hormone Interactions: Other hormone reactions
A
- Inactivate immune cells
- Block other signaling pathways
14
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling
A
- Signals from hormones only effect their specific target cell to ensure the hormonal signal only effects the target tissue
15
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling to effect
A
- Cellular metabolism or affect DNA transcription
16
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling: Types of Receptors and Location
A
- Polypeptide: Integrated into the cell membrane
- Steroid and Thyroid hormone receptors: Integrated into the cytosol
17
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling: Lock and Key Theory
A
- A given hormone interacts with a given receptor specifically designed for it
18
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling: Cross Reactivity
A
- A given hormone partially interacts with a receptor not designed for it causing a signal
19
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling: Allosteric Binding Sites
A
- Binding sites on hormonal receptors that allow for other substances to bind to them causing enhancement or reduction of the hormones effects
20
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling: Aggregated Form
A
- Some hormones need to be in their aggregated form to produce the optimal signal via the receptor.
- (several of the same hormone bound together)
21
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling: Over signaling and Downregulation
A
- Receptors can become unresponsive to hormone signaling due to over stimulation by a hormone
22
Q
Role of Receptors in Mediating Hormonal Changes: Hormonal Signaling: Alterations
A
- Receptors have the ability to:
- Increase or decrease their binding sensitivity
- The actual number of receptors present.
23
Q
Categories of Hormones: Steroid Hormones: Produced Via
A
- Adrenal cortex
- Gonads
24
Q
Categories of Hormones: Steroid Hormones: Solubility and Type of Diffusion
A
- Fat soluble
- Passively diffuse across the cell membrane
25
Categories of Hormones: Steroid Hormones: Passive Diffusion Steps
- Diffuses across the sarcolemma
- Binds with its receptors to form a hormone receptor complex (H-RC)
- Conformational shift in the receptor
- Activation of the receptor
- The H-RC then binds to another H-RC and moves to the nucleus where it arrives at the DNA in order to expose transcriptional units that code for synthesis of the specific proteins
26
Categories of Hormones: Steroid Hormones: Passive Diffusion Steps: Effects of the H-RC on DNA
- H-RC opens the double stranded DNA in order to expose transcriptional units that code for specific proteins
- Transcription of a specific gene takes place
- Messenger RNA moves into the sarcoplasm
- mRNA is translated by the ribosome into the specific protein promoted by the steroid hormone
27
Categories of Hormones: Peptide Hormones
- Made up of chains of amino acids
28
Categories of Hormones: Peptide Hormones: Examples
- Growth hormone
| - Insulin
29
Categories of Hormones: Peptide Hormones Solubility and Type of Diffusion
- Not fat soluble
- Does not cross the cell membrane
- Regulated via negative feedback
30
Categories of Hormones: Peptide Hormones: Signlaing
- Hormone effects a conformational change in the receptor induced by hormone binding that causes secondary messengers to propagate a signal into the cell
31
Categories of Hormones: Peptide Hormones: Affect Changes To
- Metabolic processes
- DNA transcription
- mRNA translation initiation at the ribosome
32
Categories of Hormones: Amine Hormones: Synthesized from
- Tyrosine
| - Tryptophan
33
Categories of Hormones: Amine Hormones: Signaling
- Similar to peptide hormones interact via a secondary messenger
- Not regulated via negative feedback
34
Heavy Resistance Exercise and Hormonal Increases: Hormone Signals
- Amount and type of physiologic stress
- Metabolic demands
- Changes in resting metabolism
35
Heavy Resistance Exercise and Hormonal Increases: Heavy resistance training increases
- Androgen receptors in the muscle
36
Heavy Resistance Exercise and Hormonal Increases: Responses to Resistance Training Based on Intensity
- Appropriate intensity causes anabolic reactions that stimulate muscle growth
- Excessive stress causes catabolic reactions that degrade muscle and inhibit anabolic hormone binding to receptors as well as down regulate the receptors in the muscle
37
Heavy Resistance Exercise and Hormonal Increases: The magnitude of hormonal response depends on
- The amount of tissue stimulated
- The amount of tissue remodeling
- The amount of tissue repair
38
Mechanisms of Hormonal Interactions: Effects of training on untrained individuals
- Acute increases in blood concentrations may increase the probability of interaction
39
Mechanisms of Hormonal Interactions: Effects of training on trained individuals
- The hormonal exposure will be less effective due to the muscle already being trained and having less potential for more growth
40
Mechanisms of Hormonal Interactions: Down regulation occurs due to
- Disease that causes hormones to be chronically elevated
| - Exogenous drug use
41
Mechanisms of Hormonal Interactions: Neural Signaling
- Neural activation of muscle fibers can increase hormone binding affinity
42
Hormonal Changes in Peripheral Blood
- Large increases in peripheral blood concentrations are generally assumed to cause higher probabilities of hormone interaction with receptors
43
Hormonal Changes in Peripheral Blood: Dependent on
- Status of receptors ability to bind with the target hormone
44
Hormonal Changes in Peripheral Blood: Physiologic mechanisms that contribute to changes in peripheral blood concentrations
- Circadian Rhythm
- Fluid volume
- Tissue clearance rates
- Venous pooling of blood
- Hormone interactions with binding proteins
45
Adaptions in the Endocrine System
- Amount of synthesis and storage of hormones
- Transport of hormones via binding proteins
- Time needed for the clearance of hormones through liver and other tissues
- Amount of hormonal degradation that takes place over a given period of time
- How much blood to tissue fluid shift occurs with exercise stress
- How tightly the hormone binds to its receptor
- How many receptors are in the tissue
- The change in the content and in some cases the size of the secretory cells in the gland
- The magnitude of the signal sent to the cell nucleus by the H-RC or secondary messenger
- The degree of interaction with the cell nucleus
46
Adaptions in the Endocrine System: Duration of Training and effects on hormonal responses
- Hormonal responses exist to maintain homeostasis
- Sharp changes to hormones in short duration=acute resistance exercise
- Subtle changes to hormones over longer periods=chronic changes to prolonged resistance training
47
Primary Anabolic Hormones: Testosterone Circulation and Binding
- Blood circulating concentrations increase with resistance training
- The number of binding receptors is more important than the total blood concentration
- Heavy resistance training causes an increase in the number of receptor binding sites available on skeletal muscle
48
Primary Anabolic Hormones: Testosterone and Growth Hormone
- Interact with one another to enhance testosterone protein synthesis and muscle building effects
49
Primary Anabolic Hormones: Testosterone and the Nervous System
- Testosterone interacts with receptors on neurons
- Increase amounts of neurotransmitters
- Influence structural protein changes
50
Primary Anabolic Hormones: Testosterone with Anaerobic and Aerobic Resistance Training
- Anaerobic=Increases in testosterone for increased muscle hypertrophy and protein synthesis
Aerobic=Increases for protein synthesis due to potentially catabolic effects of aerobic training on the muscle (Degradation of muscle due to catabolism=more testosterone for muscle rebuilding)
51
Primary Anabolic Hormones: Testosterone Increases in Boys and Younger Men due to
- Large muscle group exercises
- Heavy Resistance Training
- Moderate to high volume of exercises achieved with multiple sets, multiple exercises or both
- Short rest intervals
- Two years or more of resistance training experience
52
Primary Anabolic Hormones: Testosterone: Dirunal Changes
- Natural fluctuations in hormone concentrations throughout the day
- Hormonal changes throughout the day can be effected by long duration strength training
53
Primary Anabolic Hormones: Testosterone: Sex differences
- Testosterone is highest in men in the morning
- Women have lower total concentrations but upregulate testosterone faster in response to resistance training possibly due to the body using available testosterone faster
54
Free Testosterone and Sex Hormone Binding Globulin
- The amount of free unbound testosterone circulating in the blood is the important factor for hormone binding.
- Total concentrations of testosterone matters to the degree in which somebody with much more total testosterone may have more free unbound testosterone.
- Younger men tend to have more free testosterone and thus more circulating unbound testosterone than older men.
- Bound testosterone does not play as big a roll in hormonal interactions
- Testosterone is a major player in anabolic responses to resistance training in younger men
55
Testosterone Responses in Women
- Women have less testosterone than men
- Women do not have large acute increases in testosterone following resistance training
- Women are more sensitive to increases in testosterone
56
Training Adaptions to Testosterone
- Testosterone increases due to demands of an exercise program
- Receptors then increase binding or or do not depending on the need
- Training time and experience play important roles in altering exercise induced concentrations
- Testosterone effects on muscle cells may change as the upper limits of muscle cell size are achieved
- Testosterone can play a role even in highly experienced weight lifters
- Resistance training increase the androgen receptor content and binding of hormones to receptors.
57
Growth Hormone
- Several different variants and subtypes
- 22 kDa form has been the primary studied variant
- Several other variants have been identified
- Several variants are bound to binding proteins or aggregated making them heavier and less bioavailable, however, they still play a role in physiologic reactions
- The whole GH super family plays a role in physiologic responses to things like resistance training
58
Growth Hormone Physiologic Effects
- Decrease glucose utilization
- Decrease glycogen synthesis
- Increase amino acid transport across cell membranes
- Increase protein synthesis
- Increases utilization of fatty acids
- Increases lipolysis
- Increases availability of glucose and amino acids
- Increases collagen synthesis
- Stimulates cartilage growth
- Increases retention of nitrogen, sodium, potassium, and phosphorus
- Increases renal plasma flow and filtration
- Promotes compensatory renal hypertrophy
- Enhances immune cell function
59
Growth Hormone: 22kDa stimulates
- IGF release
- Increased availability of amino acids for protein synthesis
- These result in tissue repair stimulation and growth
60
Growth Hormone: Diurnal Fluctuation
- Highest GH stimulation at night
- Release is in a pulsatile pattern
- Pulsatile frequency and amplitude increases following resistance exercise
61
Growth Hormone: Binding
- Binds to plasma membrane bound receptors on target cells
62
Growth Hormone Response to Stress
- Reduced O2 intake simulates GH release
- Increased Hydrogen ion (decreased pH) stimulates GH release
- Increased lactate concentrations stimulate GH release
63
Growth Hormone Response to Stress: Intensity of Resistance Training
- Low intensity high rep does not have a large impact on GH release of 22kDa variant
- High intensity low rep and low rest period does have an impact on increasing GH release of 22KDa variant
64
Growth Hormone Responses in Women
- Women have higher concentrations of GH due to the fluctuations of their menstrual cycle
- GH levels in the early follicular phase are much higher than in men
- Female GH response cycles may vary with the menstrual cycle
- Male and Female responses to resistance exercise where the same when the same training protocol with the same parameters were compared
- Women show increases to aggregates of GH molecules more so than the 22kDa form. (Those bound together like a dimer 44kDa, or 66kDa, or 88kDa). 22kDa does not show as much of a change to resistance training.
- Resistance training is a much higher stimulus than aerobic exercise to GH concentrations in women.
65
Training Adaptions to Growth Hormone
- Typical trends for training related changes to GH area reduction in 22 kDa Gh response to an absolute exercise stress and alterations in 22kDa pulsatility characteristics
- Exercise induced responses to 22kDa GH are what change with training with little change in the resting concentrations.
- In contrast the bioactive form of GH resting concentrations see the most change
- Subtle alterations to some bioactive fractions of higher than 22kDa molecular weight
66
Insulin Like Growth Factors
- GH 22kDa stimulates the release of IGF's
| - IGF's travel in the blood bound to binding proteins and interact with receptors at the cellular level
67
Insulin Like Growth Factors: Binding Proteins
- Six different types of IGF-I binding protein have been identified
- Binding proteins 1 and 3 being the most extensively studied
- Act as a reservoir for IGF holding it until the cellular receptor stimulates release
68
Exercise Responses to Insulin Like Growth Factors
- Mechanical stretch to skeletal muscle causes the production and release of IGFs often referred to as mechano growth factor.
- IGF does not follow a classic endocrine response (stimulus=release of more IGF)
- IGF release with exercise may be dependent upon starting concentrations. (High starting concentration=low release. Low starting concentration=high release)
69
Training Adaptations to Insulin Like Growth Factors
- Some data suggests exercise mode specific adaptions in the circulating IGF-1 system can occur but more information is needed
70
Adrenal Hormones: Anatomy
- Two major divisions medulla and cortex
- Medulla is stimulated directly by the nervous system and provides a fast and immediate response
- The cortex is stimulated by adrenocorticotropic hormone released from the anterior pituitary gland
71
Adrenal Hormones: Hormones responsible in training and conditioning
- Cortisol
- Glucocorticoid
- Catecholamines
- Enkephalin containing polypeptides
72
Cortisol
- Primary signal for carbohydrate metabolism and is related to glycogen stores
- Has a circadian pattern. Highest in the morning and decreases throughout the day
73
Role of Cortisol
- Exerts a catabolic effect by converting amino acids into carbohydrates
- This increases the level of proteolytic enzymes that break down proteins
- Inhibits protein synthesis
- suppresses many glucose dependent processes such as glycogensis and immune cell function
74
Role of Cortisol: Greater catabolic effect on
- Type II fibers due to higher protein concentrations
75
Role of Cortisol: Effects blocked by
- Testosterone and Insulin
- If testosterone and insulin are bound catabolic effects are blocked
- If Cortisol is bound catabolic effects are not blocked
76
Resistance Exercise Responses to Cortisol
- Cortisol increases with resistance exercises especially high intensity low rest resistance exercise
- Adapted resistance trainers may have a diminished effect of cortisol and an enhanced effect of testosterone
- Increases in cortisol are accompanied by increases in GH suggesting both are required for the muscular remodeling process.
- Men show a slightly higher response to cortisol following resistance raining than women.
- With heavy training glucocorticoid receptors in immune cells decrease during training and increase during recovery reducing B cell activity during recovery
77
Catecholamines
- Norepinephrine and dopamine
- Act as central motor stimulators and peripheral vascular dilators
- Enhance enzyme systems and calcium release
78
Role of Catecholamines
- Increase force production via central mechanisms and increased metabolic enzyme activity
- Increase muscle concentration rate
- Increase blood pressure
- Increase energy availability
- Increase muscle blood flow
- Augment secretion rates of other hormones such as testosterone
79
Catecholamines: Response to exercise Intensity
- High intensity high rep, low rest training keeps norepinephrine and epinephrine high in recovery
- Epinephrine has been correlated with lactate concentrations
- Long term continued high stress can cause adrenal exhaustion and reduced ability to release catecholamines, delaying recovery.
80
Training Adaptations of Catecholamines
- Heavy resistance training has been shown to increase the athletes ability to secrete higher amount of epinephrine during maximal exercise.
- Training over periods end to cause reduced catecholamine response to singular low intensity lifts.
81
Other Hormonal Considerations
- Insulin, thyroid hormone, and beta endorphins have been implicated in growth
- Changes to insulin resistance in resistance training athletes are due to longer term changes to 24 hour secretion rates, sensitivity of receptors, and binding interactions
- Little change takes place to the role of thyroid hormones with resistance training
- Although little change takes place in these hormones they are important for resistance exercises as they have important permissive effects in metabolic control, amino acid synthesis and augmentation of other hormonal release mechanisms.
82
Blue Box: How can athletes manipulate the endocrine System with Resistance Training?: General
- More muscle fiber recruitment=more potential for increased remodeling
- Only muscle fibers activated by resistance raining are subject to adaption including hormonal adaptation.
83
Blue Box: How can athletes manipulate the endocrine System with Resistance Training?: To Increase Serum Testosterone
- Large muscle group exercise
- Heavy resistance
- Moderate to high volume achieved with multiple sets or multiple exercises
- Short rest intervals
84
Blue Box: How can athletes manipulate the endocrine System with Resistance Training?: To increase 22kDa Growth Hormone
- Workouts with higher lactate concentrations and associated acid base disruptions. That is high intensity, high rep, short rest
- Supplement diet with carbohydrates and protein before and after workouts
85
Blue Box: How can athletes manipulate the endocrine System with Resistance Training?: Optimize responses to Adrenal hormones
- High volume, large muscle groups, short rest periods, however be careful to vary training so as to avoid over training effects and chronic adrenal cortex activation.
- Be sure to include recovery days.
- Vary training stimulus and rest intervals.
