Differences Between Hormones - difference between the action of protein and steroid hormones (Mar/07/2006 )

Hello,

Biology 30 teacher here just wondering if I could obtain some external sources for a new lab for my class. I need some examples regarding the differences between the actions of protein and steroid hormones. I already understand that the major difference > Steroid hormones are crucial substances for the proper function of the body. They mediate a wide variety of vital physiological functions ranging from anti-inflammatory agents to regulating events during pregnancy. Although I am in need of more differences in order to conduct this lab. I have been trough multiple text books and websites failing to come up with usefull information. Please post any differences and there explainations so that I can choose the appropriate response.

Thank You,

Greg

I'm not sure exactly what sort of detail you want your replies in but here are some major differences between peptide and steroid hormones:

1. Steroid hormones (e.g., dihydrotestosterone) are lipophilic and can enter cells easily; peptide hormones (e.g., insulin) are charged and cannot cross the cell membrane

2. Due to the difference in point 1. steroid hormone receptors (the proteins in the cell that convert the signal into a response) are cytoplasmic and migrate to the nucleus when bound by ligand. Peptide hormone receptors are generally plasma membrane proteins with several transmembrane spanning regions.

3. Via there receptors steroids affect gene expression whereas peptide hormones generally evoke a protein phosphorylation cascade.

4. Steroid hormones can accumulate in adipose tissue, peptides tend not to.

5. The half-life in plasma of a steroid hormone is generally much longer than that of a peptide hormone. Half life of insulin is measured in minutes, that of testosterone in days.

There are plenty of other tiny little things but I don't know if this is the sort of thing you're after