Hormonal Control of Animal Behavior: Part 1

Question 1

What are hormones?

Answer 1

a regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action.

Effects probability of displayed behavior (DOES NOT CAUSE)

Organic chemicals secreted by ductless glands, produce and chaotically sent away (towards no actively seeked location)

Travel in tissue fluids (blood), act in small quantities

Question 2

Classes of hormones

Answer 2

peptide hormones, protein hormones, steroid hormones (sex steroid and adrenal steroid hormones)

Question 3

Peptide hormones

Answer 3

short chain of amino acids

example: oxytocin and vasopressin

Question 4

Oxytocin

Answer 4

example of peptide hormone

(9AA) – trigger uterine conrtactions, milk production, and influences social behavior

Question 5

vasopressin

Answer 5

example of peptide hormone

(9AA) – influences social behavior, anti-diuretic hormone (which is important for water retention)

Question 6

Protein hormones

Answer 6

longer (compared to others) chain of amino acids

examples: insulin, glucagon

Question 7

Insulin

Answer 7

example of protein hormone

(51 amino acids) – lowers blood glucose levels of glucose taken up from food

Question 8

Glucagon

Answer 8

example of protein hormone

(29 AA) – raises blood glucose

Question 9

Steroid hormones

Answer 9

More evolutionary conserved, means hormones same in dogs/cats/humans/etc.

All steroid hormones originate as CHOLESTEROL (except vitamin D)

2 Subgroups: Sex steroid hormones and Adrenal steroid hormones

Question 10

Sex steroid hormones

Answer 10

Has 3 sources in vertebrates: gonads, brain, and adrenal gland(in kidneys)

Types:

Androgens (testosterone, dihydrotestosterone, androstenedione)

Estrogens: estradiol, estrone, estroil)

Progestins (progesterone)

Question 11

Adrenal steroid hormones

Answer 11

One source: adrenal gland!!

Medulla: production of hormones that alter animal’s physiology

Cortex

Question 12

Medulla hormones examples

Answer 12

Example: adrenaline/epinephrine – increases heart rate, blood pressure

Example: noradrenalin – decreases heart rate, drops blood pressure

Question 13

Cortex hormone examples

Answer 13

Glucocorticoids:
* Cortisol in humans and mammals, corticosterone in rodents
* Regulate carbohydrate metabolism
* Anti-inflammatory, suppression of immune system

Androgens
Aldosterone

Question 14

How are hormones made in protein and peptide hormone production

Answer 14

Occurs in hypothalamus

DNA from Nucleus becomes mRNA, travels to RER (rough endoplasmic reticulum)

Modified mRNA travels from RER to golgi; Golgi takes it through modifications of the amino acids

Amino acids are then packed into vesicles and wait for use

Overall: pre-pro-hormone(immature) -> pro-hormone -> hormone (mature)

Only mature hormones usable, and must go through golgi (signals release)

Question 15

Describe how hormones are made in steroid hormone production

Answer 15

SER involved, has cholesterol

SER creates enzymes

Enzymes undergo secretion, have addition of carrier protein at the time of secretion; This helps it make its way through the blood

Question 16

why would a steroid hormone need carrier protein, while the protein and peptide hormones do not?

Answer 16

Steroid/cholesterol are oil like, and blood is mostly water

Water and oil do not mix, cholesterol will not go through blood

Question 17

How do hormones act on a cell to alter behavior in peptide and protein hormones?

Answer 17

A receptor outside the cell pulls the peptide hormone towards it

The phospholipid bi-layer, made of lipids, have selective doors to only allow certain things through; Peptide hormone cannot access it, so receptor on outside

Peptide hormone contacts G-coupled receptor, alpha from receptor contacts adenylate cyclase to make cyclic AMP

cAMP is a 2nd messenger that aomplifies signals; protein kinase phosphorylates cAMP, creates change in cell activity, leads to change in behavior; FAST (takes minutes)

Question 18

How do hormones in steroid hormones act on a cell to alter behavior?

Answer 18

Since they are fats, they can go through phospholipid bilayer easily, no special conditions needed

Receptors must dimerize (2 bind together)

DNA has HRE(hormone response element), dimer binds to HRE, changes transcription and translation (increase or decrease in it)

Results in probability of change in behavior
* LONGER (takes hours)
* Can be manipulated for experimentation

Question 19

How is hormone secretion regulated?

Answer 19

address later