Vol. 278, Issue 2, E263-E272, February 2000
A mathematical model quantifying GnRH-induced LH secretion
from gonadotropes
J. Joseph
Blum1,
Michael C.
Reed2,
Jo Ann
Janovick3, and
P. Michael
Conn3
1 Department of Cell Biology,
Duke University Medical Center, Durham 27710;
2 Department of Mathematics,
Duke University Medical Center, Durham, North Carolina 27708; and
3 Oregon Health Sciences
University, Beaverton, Oregon 97006
A mathematical model is developed to investigate the rate
of release of luteinizing hormone (LH) from pituitary gonadotropes in
response to short pulses of gonadotropin-releasing hormone (GnRH). The
model includes binding of the hormone to its receptor, dimerization,
interaction with a G protein, production of inositol 1,4,5-trisphosphate, release of
Ca2+ from the endoplasmic
reticulum, entrance of Ca2+ into
the cytosol via voltage-gated membrane channels, pumping of
Ca2+ out of the cytosol via
membrane and endoplasmic reticulum pumps, and release of LH. Cytosolic
Ca2+ dynamics are simplified
(i.e., oscillations are not included in the model), and it is assumed
that there is only one pool of releasable LH. Despite these and other
simplifications, the model explains the qualitative features of LH
release in response to GnRH pulses of various durations and different
concentrations in the presence and absence of external
Ca2+.
calcium; G protein; endoplasmic reticulum; inositol
1,4,5-trisphosphate; luteinizing hormone
