(07-09-2014, 10:56 PM)Lotus Wrote: A target cell may have between 2,000 and 100,000 receptors for a particular hormone.

Receptors, like other cellular proteins, are constantly being synthesized and broken down. Here's an important (pro active) step:

CYCLE YOUR NBE PROGRAMS WITH BREAKS!

Tolerance occurs when the person no longer responds to the drug in the way that person initially responded. Stated another way, it takes a higher dose of the drug to achieve the same level of response achieved initially.

Some drugs require a period of abstinence periodically to allow the cell to return to normal receptor density.