MadSci Network: Cell Biology
Query:

Re: How does a hormone interact with its receptor?

Date: Mon Jun 25 00:20:08 2001
Posted By: Elena Rodriguez, Grad student, Molecular and Cell Biology, University of California, Berkeley
Area of science: Cell Biology
ID: 988905499.Cb
Message:

Hi Karim,
this is a very good question!
Well, it depends on what KIND of hormone you are talking about.
Generally, there are two kinds: protein hormones and lipid (steroid) 
hormones.  Both kinds of hormones have receptors, but the work differently 
to make changes in cells.
Protein or peptide hormones are soluble or polar.  Because the plasma 
membrane is made out of a lipid bilayer- peptide hormones can't pass 
through.  So, in order for a hormone to send a signal to a cell, it binds to 
a protein rececptor on the surface of the cell that is anchored in the 
plasma membrane.  The receptor can bind specifically to the peptide hormone 
because the shape or binding pocket of the receptor is shaped especially for 
the structure of the peptide hormone.  Once the receptor is bound to the 
hormone, the inside portion of the receptor (the cytoplasmic face of the 
receptor) is "activated" and can send messages inside the cell.
Steroid hormones are derived from the lipid, cholesterol, and are nonpolar. 
They can readily pass through any cell's plasma membrane.  But, these 
hormones also have receptors. The receptors of steroid hormones are not 
membrane-bound but are floating in the cytoplasm. These receptors also have 
a binding pocket that is shaped especially for the structure of the steroid 
hormone.  Upon binding, the receptor now can "activate" a transciption 
factor, and induce transcription of specific genes to make proteins. 
The steroid hormone can direct that transcription and expression of these 
genes into protein while the peptide hormone works to activate proteins that 
are already made.
I hope this helps!
Sincerely,
Elena Rodriguez



Current Queue | Current Queue for Cell Biology | Cell Biology archives

Try the links in the MadSci Library for more information on Cell Biology.



MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci


MadSci Network, webadmin@www.madsci.org
© 1995-2001. All rights reserved.