Hormonal Control of Animal Behavior: Part 1 Flashcards
What are hormones?
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
Classes of hormones
peptide hormones, protein hormones, steroid hormones (sex steroid and adrenal steroid hormones)
Peptide hormones
short chain of amino acids
example: oxytocin and vasopressin
Oxytocin
example of peptide hormone
(9AA) – trigger uterine conrtactions, milk production, and influences social behavior
vasopressin
example of peptide hormone
(9AA) – influences social behavior, anti-diuretic hormone (which is important for water retention)
Protein hormones
longer (compared to others) chain of amino acids
examples: insulin, glucagon
Insulin
example of protein hormone
(51 amino acids) – lowers blood glucose levels of glucose taken up from food
Glucagon
example of protein hormone
(29 AA) – raises blood glucose
Steroid hormones
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
Sex steroid hormones
Has 3 sources in vertebrates: gonads, brain, and adrenal gland(in kidneys)
Types:
Androgens (testosterone, dihydrotestosterone, androstenedione)
Estrogens: estradiol, estrone, estroil)
Progestins (progesterone)
Adrenal steroid hormones
One source: adrenal gland!!
Medulla: production of hormones that alter animal’s physiology
Cortex
Medulla hormones examples
Example: adrenaline/epinephrine – increases heart rate, blood pressure
Example: noradrenalin – decreases heart rate, drops blood pressure
Cortex hormone examples
Glucocorticoids:
* Cortisol in humans and mammals, corticosterone in rodents
* Regulate carbohydrate metabolism
* Anti-inflammatory, suppression of immune system
Androgens
Aldosterone
How are hormones made in protein and peptide hormone production
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)
Describe how hormones are made in steroid hormone production
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
why would a steroid hormone need carrier protein, while the protein and peptide hormones do not?
Steroid/cholesterol are oil like, and blood is mostly water
Water and oil do not mix, cholesterol will not go through blood
How do hormones act on a cell to alter behavior in peptide and protein hormones?
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)
How do hormones in steroid hormones act on a cell to alter behavior?
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
How is hormone secretion regulated?
address later
