Replies to post #3703 on Repros Therapeutics, Inc. (RPRX)

[docbanker]

cmon.
you know that some drugs in same class have different affinities for receptors.
Look at clomid vs androxal - different isomers (both isomers for clomid vs single isomer for androxal) of the same molecule and it has a hugely different effect on hypothalmus/pituitary.

[dewophile]

How can you be a mixed agonist/antagonist for the same receptor? In a key and lock analogy you are either blocking the lock - or picking the lock.


not so long ago this was the general sentiment - today we know the lock and key analogy is an oversimplification. there are multiple locks and keys, and often multiple modifiers (coactivaros/suppressors) that can act on a partiuclar lock and/or key, so that the net effect is a (often tissue-specific) unique response to a particular drug/hormone. the science is more fleshed out for estrogen than progesterone, so i suggest you read a good review (sorry don't have a reference handy) on SERMs to get an idea for the complexity of the system. note that the endometrium is comprised of not just one tissue type, but rather several distinct elements - glands, stroma, vasculature - so the effects on the endometrium may be distinct and unique depending on the profile of the drug