Average the Blank control values, and set the parameter Top to be a constant value equal to the mean of the blanks.Fit the data only, ignoring the Blank control values.When fitting this curve, you need to decide how to fit the top plateau of the curve. The data of the experimental dose-response curve (red dots) extend all the way between the two control values. The ones on the right are in the presence of a maximal concentration of a standard inhibitor, so define "0%". The ones on the left (Blank) have no inhibitor, so define "100%". The green symbols show measurements made with controls. Just stand on your head when you view the figures. All the ideas can be applied to stimulatory curves and EC50 (E for effective) as well. The rest of this article is about IC50 (I for inhibition, for downward sloping dose-response curves). But when you actually go to fit data to determine these values, there are several complexities and ambiguities. The IC50 is the concentration of an inhibitor where the response (or binding) is reduced by half. The EC50 is the concentration of a drug that gives half-maximal response. The concepts of IC50 and EC50 are fundamental to pharmacology.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |