Intrinsic activity is defined as what?

Intrinsic activity is defined as what?

• A. The binding affinity of a drug for a receptor
• B. The drug's potency
• C. The ability of a bound drug to activate a receptor and produce a response
• D. The rate at which the receptor is degraded.

Answer: (C)

Intrinsic activity is the ability of a drug, once it is bound to its receptor, to activate that receptor and produce a biological response. This property reflects efficacy rather than binding strength. A drug may bind tightly (high affinity) but have low intrinsic activity if it doesn’t effectively trigger receptor activation; or bind and strongly activate the receptor (high intrinsic activity). Potency, on the other hand, is about the amount of drug needed to produce a given effect and depends on both affinity and intrinsic activity, but intrinsic activity itself is specifically about the activation and resulting response. The rate at which the receptor is degraded is not related to how effectively the bound drug activates the receptor.

Intrinsic activity is the ability of a drug, once it is bound to its receptor, to activate that receptor and produce a biological response. This property reflects efficacy rather than binding strength. A drug may bind tightly (high affinity) but have low intrinsic activity if it doesn’t effectively trigger receptor activation; or bind and strongly activate the receptor (high intrinsic activity). Potency, on the other hand, is about the amount of drug needed to produce a given effect and depends on both affinity and intrinsic activity, but intrinsic activity itself is specifically about the activation and resulting response. The rate at which the receptor is degraded is not related to how effectively the bound drug activates the receptor.