Endocrinology: CortisolBiology 304 LabGina Neonakis & Michelle McPhersonMarch 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 Methods6 hormones ; ACTH, cortisol, LH, TSH, TSR and testosteroneSix sets of four adult male rats One experimental set One control setFed rat chow and were given fresh waterTwo experimental rats were injected everyday with specified

hormoneTwo control rats injected everyday with salineTwo week injection periodEuthanized by a intraperitoneal injection

Results

Normal body mass = 172

Castrate body mass = 195

Pituitary 9.6 9.4Thyroid 212 214Thymus 364 372Adrenals 28 26Seminal Vesicles

484 454

Prostate 431 394Testes 3201 n/a

Hormone 11

Normal body mass = 300 g

Castrate body mass = 270 g

Pituitary 12.9 12.9

Thyroid 250 250

Thymus 475 470

Adrenals 40 40

Seminal Vesicles

500 460

Prostate 425 392

Testes 3200 n/a

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

ResultsTRH TSH ACTH Cortisol Testosterone

normalTestosterone castrate

LH norm

LH castrate

Pituitary + - - - - - - -

Adrenal + +

Thyroid + + -

Thymus -

Testes - +

Prostate + + +

Seminal Vesicles

+ + +

Body weight - - - - + + +

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

Questions?