Endocrinology: Cortisol Biology 304 Lab Gina Neonakis & Michelle McPherson March 6, 2013
What is Cortisol? • Regulates blood pressure, glucose metabolism, insulin release, immune function and inflammatory response. • Secreted by the adrenal gland • Termed the “Stress Hormone” • Hydrocortisone creams
Cortisol Secretion • Glucocorticoid • Brain perceives stress ↓Hypothalamus- CRH ↓Pituitary Gland- ACTH ↓Adrenal Gland- Cortisol Figure 1. Hormonal pathway caused by stress (Talbott & Kraemer, 2007).
Cortisol Rhythm • Follows a circadian rhythm • Highest level 6:00am-8:00am • Lowest level 12:00am-2:00am Figure 2. A normal cortisol rhythm (Talbott & Kraemer, 2007).
Figure 3. Normal stress response (Talbott & Kraemer, 2007). Figure 4. Modern human stress response (Talbott & Kraemer, 2007).
Materials and Methods • 6 hormones ; ACTH, cortisol, LH, TSH, TSR and testosterone • Six sets of four adult male rats • One experimental set • One control set • Fed rat chow and were given fresh water • Two experimental rats were injected everyday with specified hormone • Two control rats injected everyday with saline • Two week injection period • Euthanized by a intraperitoneal injection
Results Hormone 11 Controls
Results • When comparing the control rats with the experimental rats these are the size differences we observed: • Pituitary: decrease • Thyroid: decrease • Thymus: decrease • Adrenals: decrease • Seminal Vesicles: decrease • Prostate: no significant change • Testes: no change and n/a
Results • Unknown hormone 11 is Cortisol • Effects of high cortisol : fatigue, lowered immunity, increase fat deposits, can cause Cushing’s disease • Ways to prevent hyper secretion of cortisol : yoga, exercise, stress relieving activities