Illinois State University Hormonal Regulation of Exercise Chapter 21 and 22

Illinois State University The Endocrine System l Gland l Hormone l Target organ or tissue.

Illinois State University Hormones l Hormones can be classified as either steroidal or nonsteroidal. »Steroid hormones are lipid soluble, and most are formed from cholesterol. »Nonsteroid hormones are proteins, peptides, or amino acids.

Illinois State University Hormones l Hormones are generally secreted into the blood and then circulate through the body to exert an effect only on their target cells.

Illinois State University Hormones l Steroid hormones pass through cell membranes and bind to receptors inside the cell. »They use a mechanism called direct gene activation to cause protein synthesis.

Illinois State University Hormones l Non-steroidal hormones cannot enter cells easily, so they bind to receptors on the cell membrane. »This activates a second messenger within the cell which in turn can trigger numerous cellular processes.

Illinois State University Hormones l Secretion of most hormones is regulated by a negative feedback system.

Illinois State University Hormones l The number of receptors for a specific hormone can be altered to meet the body’s demands.

Illinois State University Hormones l Key point - the pituitary gland was once thought to be the master endocrine gland solely in control of many other glands and organs.

Illinois State University Control l It is now recognized that the pituitary gland is largely controlled by the hypothalamus.

Illinois State University Hormones See Table 21.3 (p. 629) for listing of glands, hormones, and major function.

Illinois State University Pituitary Hormones Anterior Lobe l Somatotropin (hgH) - Impacts all cells of the body. »Major role in maturation, protein synthesis, use of fat, and CHO sparing.

Illinois State University Pituitary Hormones Anterior Lobe l Andrenocorticotropin (ACTH) - Impacts the adrenal cortex and regulates adrenal cortex hormone secretion.

Illinois State University Pituitary Hormones Posterior Lobe l Antidiruretic Hormone (ADH or vasopressin) - impacts the kidneys. »Regulates water excretion and blood pressure by vasoconstriction.

Illinois State University Thyroid Hormone l Thyroxine and triiodothyronine - Impact all cells in the body. »Increases rate of cellular metabolism, increases heart rate and force of contraction.

Illinois State University Adrenal Hormones Medulla l Epinephrine - Impacts most cells of the body. »Mobilizes glycogen, increases skeletal muscle blood flow, increases heart rate and contractility, increases oxygen consumption.

Illinois State University Adrenal Hormones Medulla l Norepinephrine - impacts most cells of the body through vasoconstriction which increases blood flow, increases heart rate and contractility, increases VO 2.

Illinois State University Adrenal Hormones Cortex l Mineralcorticoids (aldosterone) - impacts kidneys causing Na retention and K excretion.

Illinois State University Adrenal Hormones Cortex l Glucocorticoids (cortisol) - impacts most cells of the body. »Controls metabolism of all fuels and has an anti-inflammatory action.

Illinois State University Adrenal Hormones Cortex l Androgens and estrogens - impacts sex organs. »Responsible for development of secondary sexual characteristics.

Illinois State University Pancreatic Hormones l Insulin - impacts all cells of the body. »Regulates blood glucose levels. »Increases the utilization of glucose and the synthesis of fat.

Illinois State University Pancreatic Hormones l Glucagon - impacts all cells of the body. »Increases blood glucose levels and stimulates the breakdown of protein and fat.

Illinois State University Gonadal Hormones Testes l Testosterone - affects sex organs and muscles. »Responsible for the development of male secondary sexual characteristics.

Illinois State University Gonadal Hormones Ovaries l Estrogen - affects sex organs and adipose tissue. »Responsible for the development of female secondary sexual characteristics.

Illinois State University Hormones and Exercise l Catecholamines - secretion increases. »Greater increase with intense exercise. »Secrete more norepinephrine than epinephrine. »Secretion increases less after training. »Significance - increased blood glucose.

Illinois State University Hormones and Exercise l Somatotropin - increases with exercise. »Increases more in unfit person. »Declines faster in fit person. »Significance - unknown?

Illinois State University Hormones and Exercise l ACTH-cortisol - increases with exercise. »Greater increase with intense exercise. »Increases less after submaximal exercise training. »Significance - increased gluconeogenesis in liver.

Illinois State University Hormones and Exercise l Testosterone - Increases with exercise. »Effect - none. »Significance - unknown?

Illinois State University Hormones and Exercise l Insulin - decreases during exercise. »Decreases less after training. »Significance - increased stimulus to utilize blood glucose.

Illinois State University Hormones and Exercise l Glucagon - Increases with exercise. »Increases less after training. »Significance - increased blood glucose via glycogenolysis and gluconeogenesis.

Illinois State University Hormones and Exercise l Renin-angiotensis-aldosterone - Increase with exercise. »Same after training in rats. »Significance - Na retention to maintain plasma volume.

Illinois State University Hormones and Exercise l ADH - Increases with exercise. »Effect - none »Significance - Causes water retention to maintain plasma volume.

Illinois State University Hormones and Metabolism l Plasma glucose is increased by the combined actions of glucagon, epinephrine, norepinephrine, and cortisol. »These hormones promote glycogenolysis and gluconeogenesis, thus increasing the amount of glucose available for use as a fuel source.

Illinois State University Hormones and Metabolism l Insulin helps the released glucose enter the cells where it can be used for energy production.

Illinois State University Insulin l But insulin levels decline during prolonged exercise, indicating that exercise facilitates the action of insulin so that less of the hormone is required during exercise than when at rest.

Illinois State University Hormones and Metabolism l When CHO reserves are low, the body turns more to fat oxidation for energy, and this process is facilitated by cortisol, epinephrine, norepinephrine, and growth hormone.

Illinois State University Hormones and Metabolism l Cortisol accelerates lipolysis, releasing free fatty acids into the blood so they can be taken up by the cells and used for energy production.

Illinois State University Cortisol l But cortisol levels peak and then return to near normal levels during prolonged exercise.

Illinois State University Hormones and Metabolism: l When this happens, the catecholamines and growth hormone take over cortisol’s role.

Illinois State University Hormones and Metabolism: l Key point - Loss of fluid (plasma) from the blood results in a concentration of the constituents of the blood, a phenomenon referred to as hemoconcentration.

Illinois State University Hormones and Metabolism: l Conversely, a gain of fluid into the blood results in a dilution of the constituents of the blood, which is referred to as hemodilution.

Illinois State University Fluid Balance and Hormones l The 2 primary hormones involved in the regulation of fluid balance are aldosterone and antidiuretic hormone (ADH).

Illinois State University Fluid Balance and Hormones: l When plasma volume or blood pressure decreases, Angiotensinogen II increases peripheral resistance, raising the blood pressure.

Illinois State University Fluid Balance and Hormones l Angiotensinogen II also triggers the release of aldosterone from the adrenal cortex.

Illinois State University Aldosterone l Aldosterone promotes sodium reabsorption in the kidneys, which in turn causes water retention, thus increasing plasma volume.

Illinois State University Fluid Balance and Hormones l ADH acts on the kidneys, promoting water conservation. »Through this mechanism, the plasma volume is increased, which results in dilution of the plasma solutes.

Illinois State University Anabolic Androgenic Steroids

Illinois State University Anabolic Androgenic Steroids

Illinois State University Anabolic Androgenic Steroids

Illinois State University Anabolic Androgenic Steroids

Illinois State University Anabolic Androgenic Steroids

Illinois State University Anabolic Androgenic Steroids

Illinois State University Anabolic Androgenic Steroids