Mechanisms of hormone action

Mechanisms of hormone action - specific physiological cell...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Mechanisms of hormone  action Hormones circulating in the blood  diffuse into the interstitial fluids  surrounding the cell. Cells with specific  receptors for a hormone respond with  an action that is appropriate for the cell.  Because of the specificity of hormone  and target cell, the effects produced by  a single hormone may vary among  different kinds of target cells. Hormones activate target cells by one  of two methods, depending on the  chemical nature of the hormone:
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Lipid-soluble hormones  (steroid hormones and hormones  of the thyroid gland) diffuse  through the cell membranes of  target cells. The lipid-soluble  hormone then binds to a receptor  protein that in turn activates a  DNA segment that turns on  specific genes. The proteins  produced as a result of the  transcription of the genes and  subsequent translation of mRNA  act as enzymes that regulate 
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: specific physiological cell activity. Water-soluble hormones (polypeptide, protein, and most amino acid hormones) bind to a receptor protein on the plasma membrane of the cell. The receptor protein in turn stimulates the production of one of the following second messengers: Cyclic AMP (cAMP) is produced when the receptor protein activates another membrane-bound protein called a G protein. The G protein activates adenylate cyclase, the enzyme that catalyzes the production of cAMP from ATP. Cyclic AMP then triggers an enzyme that generates specific cellular changes. Inositol triphosphate (IP 3 ) is produced from membrane phospholipids. IP 3 in turn triggers the release of Ca 2+ from the endoplasmic reticulum, which then activates enzymes that generate cellular changes....
View Full Document

Page1 / 4

Mechanisms of hormone action - specific physiological cell...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online