SECOND MESSENGER MECHANISMS

A Simple way to remember what substances use what second messenger mechanisms:


IP3 mechanism -

Used by:
1. All hormones produced by hypothalamus - i.e. all the Releasing hormones, oxytocin and ADH - [except CRH]
2. All hormones causing contractions [remember that IP3 causes Ca+ increase which is required for contraction] - this includes Angiotensin, Alpha-1 receptors and muscarinic receptors [pupil contraction]- also Oxytocin fits here [uterine contraction] and vasopressin

Tyrosine kinase - Used by All hormones that are "growth Factors" and Insulin


cGMP - is easy : all these are secreted by the vascular system: ANP. EDRF & NO


cAMP mechanism:
All hormones that are not steroids and thyroid and that don't fit in above logic


Steroid hormones - this one is real easy and needs no memory aid


ofcourse there will be exceptions - but those exceptions are not too imp on the MLE :-)