AJP - Regulatory, Integrative and Comparative Physiology, Vol 248, Issue 3 312-R319, Copyright © 1985 by American Physiological Society
Dynamic model of gonadotropin-releasing hormone receptor function
J. C. Zolman
Functioning gonadotropin-releasing hormone (GnRH) receptor is visualized as
an aggregate of identical subunits (not all always functional) with the
aggregate usually transformed into at least four successive structurally
distinct receptor assemblies. Receptor protein, hormone molecule(s), and
carrier(s) are main components of each functional subunit. During the
normal lifespan of the functional subunit, each carrier is responsible for
delivery of a unit amount of product, per unit time, to the cell surface
(ratio between functional carrier and bound hormone, 1:1). Association of
hormone with the receptor protein is essential, not only for the initial
formation of the functional subunits but also for subsequent conformational
changes that are in turn essential for formation of the aggregate only, or
later (in the presence of sufficiently high GnRH concentrations) for a
successive formation of a family of receptor assemblies (occurring one at a
time). The successive assemblies differ from the aggregate by being more
stable and from one another by increasing GnRH binding affinity and
apparent capacity. They resist stimulation during protracted decay
(desensitization).
