Cortisol and Stress Response in Humans

Question 1

What is the major glucocorticoid produced in the adrenal cortex?

Answer 1

Cortisol

Question 2

What does cortisol do?

Answer 2

It is actively involved in calcium absorption regulation, blood pressure maintenance, anti-inflammatory function, gluconeogenesis, gastric acid and pepsin secretion, and immune function

Question 3

Cortisol production has a _____________ rhythm. Levels peak in the __________________ and drop to their lowest levels at ________________.

Answer 3

Circadian Early morning Night

Question 4

Cortisol levels rise _______________ of the circadian rhythm in response to _____________.

Answer 4

Independently Stress

Question 5

In the blood only 1 to 15% of cortisol is in its __________ or biologically __________ form.

Answer 5

Unbound Active

Question 6

Unbound serum cortisol enters the _________ via intracellular mechanisms, and in _________ the majority of cortisol remains unbound to protein.

Answer 6

Saliva Saliva

Question 7

Salivary cortisol levels are unaffected by _______ or _________.

Answer 7

Salivary flow rate Salivary enzyme levels

Question 8

Cortisol engages in a _____________ feedback loop with the _____________.

Answer 8

Negative Hypothalamus

Question 9

Complete the following secretory pathway for the production of cortisol.

Answer 9

Hypothalamus

Paraventricular nucleus

Corticotropin releasing hormone

Anterior pituitary

Corticotrophs

Adrenocorticotropic hormone

Adrenal cortex

Zona fasciculata

Cortisol

Question 10

The term “stress” was introduced in _______ by __________, who explained the phenomenom as nonspecific bodily changes that occurred in response to physically harmful stimuli or “stressors.”

Answer 10

1935

Hans Selye

Question 11

More appropriately, ________ is defined as the sum of biological reactions to intrinsic and extrinsic stimuli that results in the perturbation from homeostatsis

Answer 11

Stress

Question 12

The bioavailability and metabolic clearance of glucocorticoids are regulated in part by ______________.

Answer 12

Binding globulins

Question 13

When are glucocorticoids biologically available and active?

Answer 13

In their free, unbound states

Question 14

The degree and duration of the _______________ in _______________ concentrations above basal levels are indicative of _________, and greater ________________ concentrations over longer periods of time are interpreted as _______________________ situations.

Answer 14

Increase in glucocorticoid concentration

Stress

Glucocorticoid concentrations

More stressful

Question 15

The hypothalamus-pituitary-adrenal axis is associated with what type of bodily response?

Answer 15

Fight or flight

Question 16

Why does the body release glucocorticoids during stressful situations?

Answer 16

Because the glucocorticoids can meet the body’s higher metabolic demands

Question 17

What does ELISA stand for?

Answer 17

Enzyme-linked immunoabsorbant assay

Question 18

What are ELISAs used for?

Answer 18

It is a technique used to detect and quantify the amount peptides, proteins, antibodies, or hormones in a sample

Question 19

In the ELISA lab, a ____________ plate was coated with ________________ to cortisol. Cortisol in standards and unknowns competed with the cortisol linked to __________________________ for antibody-binding sitese. After incubation, ___________________ are washed away. Bound ____________ is measured by the reaction of the _____________________ on the substrate _____________________ (TMB). This reaction produces a _________ color. A __________ color is formed after stopping the reaction with ______________. ______________________ is read on a standard plate reader at ___________ nm. The amount of ____________ detected, as measured by the intensity of color, is ______________ proportional to the amount of ___________ present.

Answer 19

Microtitre

Monoclonal antibodies

Horseradish peroxidase

Unbound components

Cortisol peroxidase

Peroxidase enzyme

Tetramethylbenzidine

Blue

Yellow

Sulfuric acid

Optical density

450

Cortisol peroxidase

Inversely

Cortisol

Question 20

What principle is ELISA based upon?

Answer 20

Specific binding between antibody and antigen and competitive binding

Question 21

Why was cortisol bound to horseradish peroxidase used?

Answer 21

Cortisol from the sample is placed into the microtitre plate, which has been coated with cortisol antibodies, and as such, cortisol from the sample binds the antibodies; washes wash away any unbound cortisol; addition of cortisol bound to horseradish perioxidase competes for binding with the cortisol already bound to the antibodies; upon treatment with tetramethylbenzidine (TMB) the perioxidase turns the solution blue

In other words the intensity of the color means that more cortisol bound to the perioxidase bound to the antibody, meaning that the original sample had less cortisol

Question 22

Why were washes conducted?

Answer 22

To remove any unbound cortisol

Question 23

ELISA Protocol

1. Briefly ____________ and ____________ samples for ______ minutes
2. Pipette __________ into designated wells
3. Pipette __________ into designated wells
4. Pipette __________ into ___ wells to serve as ____ value
5. Add _____________ to each well
6. ________ on ______ for _____ minutes at room temperature
7. _____ with buffer _____ times
8. Add _________ to each well
9. Incubate plate in the _____ on a _______ at _______ temperature for _____ minutes
10. Add _______ solution
11. Read plate within ______ minutes of adding _____ solution

Answer 23

Vortex, centrifuge, 15

Standards

Samples (unknowns)

Assay diluent, two, zero

Pre-diluted cortisol enzyme conjugate

Incubate, rotator, 55

Wash, four

Tetramethylbenzidine (TMB)

Dark, shaker, room, 25

Stop (sulfuric acid)

10, stop