Introduction to Hormones

Cell Signaling

How extracellular signals (like hormones) can trigger a cellular response?

Hormones

Try to fill in the blanks yourself
_________ cellular messenger.
Released from a ________     _____ .
Transported in _________ from an endocrine cell to a ________ cell (somewhere else) with a receptor.
Where is that receptor?
To answer that we have to determine the Class of hormones.

Where is that receptor?
It depends on the ________ of hormones.
There are ____ classes of hormones.

1. Steroid hormones – Estrogen, testosterone.
2. Peptide/polypeptide hormones – Insulin, glucagon.
3. Amino acid derivatives – Epinephrine.

Answers for fill in the blanks:

Inter; ductless; gland; blood; target; class; 3.

Hormones may be Polar or Non Polar.

Polar

They are water soluble and cannot diffuse through the plasma membrane and receptors are outside the membrane.

Non-Polar

They are lipid soluble and insoluble in water and can diffuse through the membrane, receptors are inside the cell.

Hormone binding

What happens when a hormone binds to a receptor?
____________    __________ occurs.
A series of steps is caused by this hormone binding event:

• alter _________ activity.
• alter ______        __________ .

Answers for fill in the blanks: 

signaling; cascade; enzyme; gene; transcription.

Signal Transduction

The process by which an extracellular signal is converted (and amplified) into a cellular response
Often involves ___________ .
1st messenger – the ___________ (or another extracellular signal that initially arrives at the target cell (receptor).
2nd messenger – a molecule made _________ the cell in response to the _______________ event (1st messenger).
Impacts activity of the cell.
Usually created in ____________ amount.
_________ signal.

Answers for fill in the blanks:

2nd messenger; hormone; inside; hormone binding; high/large; amplify.