Give three examples of catecholamines
Dopamine, epinephrine, norepinephrine
What is the first messenger?
The hormone
What are the three classes of hormones?
Steroid, peptide, and amines
What is the second messenger?
cAMP or Calcium ions
What is G-protein bound to in inactive state?
GDP
What happens once the hormone binds to its receptor on the cell membrane?
It localizes with the G-protein which then binds to GTP
What happens after GTP-G protein is activated?
It activates membrane bound adenyl cyclase
What does adenyl cyclase do?
Converts ATP to cAMP
How does active G protein become inactive again?
It hydrolyzes GTP into GDP
What does cAMP do?
4 cAMP molecules bind to the regulatory portion of PKA
What does PKA do?
It transfers the gamma phosphate of ATP to the substrate
What is the gamma phosphate?
The end phosphate of ATP
What does glycogen phosphorylase do
It catalyzes the conversion of glycogen to glucose by breaking alpha 1,4 bonds
What is the active form of glycogen phosphorylase?
Phosphorylated
How does glycogen break into glucose?
Glycogen phosphorylase breaks glycogen with a phosphate molecule
What is PLC?
Phospholipase C
What happens when gastrin binds to its receptor?
It activates a G protein which interacts with PLC
What does PLC do?
It will hydrolyze phosphatidyl-inositol-4,5-biphosphate (PIP2) into inositol-1,4,5-triphosphate and 1,2-diacylglycerol (DAG)
What is the second messenger in the case of gastrin?
IP3: inositol 1,4,5-triphosphate
Where do all steroid hormones originate from?
Cholesterol
What are androgens?
Male sex hormones
What are estrogen?
Female sex hormones
What are islets of Langerhans?
They are a group of pancreatic cells secreting insulin and glucagon
Which cells secrete insulin?
Beta cells
Which cells secrete glucagon?
Alpha cells
What is paracrine regulation?
A signal is released from one cell and influences a cell immediately next to it
Where are hormones released in paracrine regulation?
Extracellular space - not the blood
What is autocrine regulation?
They release certain chemicals that they then respond to themselves
What two hormones does the posterior pituitary gland release?
Oxytocin and ADH
What is the main function of ADH?
It stimulates water reabsorption and helps to increase blood volume aka pressure
What is diuresis?
The excessive production of urine