EC50 defines the molar concentration of an agonist that produces 50% of the maximum possible response for that agonist.
ED50 defines the dose of compound that produces 50% of its maximum response or effect in vitro or in vivo.
Efficacy describes the way that agonists vary in the response they produce when they occupy the same number of receptors. High efficacy agonists produce their maximal response while occupying a relatively low proportion of the total receptor population. Lower efficacy agonists do not activate receptors to the same degree and may not be able to produce the maximal response.
Pertaining to glands which secrete hormones (or other products) directly in to the blood. Endocrine factors generally take effect as sites distant from their release site.
Enteral administration routes include the oral, sublingual and rectal routes. Enteral administration facilitates systemic exposure to the drug.
The study of heritable changes in phenotype that does not involve changes in the underlying DNA sequence.
A loosely packed form of chromatin that is typically actively being transcribed or is accessible for transcription.
Taking place outside a living organism.
Pertaining to glands which secrete hormones (or other products) to an epithelial surface via ducts rather than directly in to the bloodstream (cf. endocrine). Exocrine glands include the salivary and sweat glands, and glands within the gastrointestinal tract.