SUBPOPULATIONS OF LUTEAL CELLS IN THE PRIMATE OVARY

The proposed research is designed to test the hypothesis that the
nonhuman primate (monkey) corpus luteum is a heterogeneous gland
consisting of dynamic subpopulations of luteal cells which differ
on the basis of structure, function and regulation by hormonal
substances. The long-term objectives include elucidation of the
origin(s), paracrine interactions and regulatory mechanisms for
luteal cell subtypes which combine to produce the normal activity
and lifespan of the primate corpus luteum. The initial aims are:
(1) to distinguish and separate luteal cells into highly-enriched
subpopulations based on differences in physical properties (cell
size and organelles) and in binding of fluorescent-tagged hormones,
(2) to characterize the ability of purified cell populations to
produce steroid hormones and prostaglandins and to respond to
luteotropic and luteolytic agents, and (3) to begin in vitro
studies on possible cell-to-cell interactions influencing the
steroidogenic activity of luteal cells. Collagenase-dispersed cells will be prepared from the corpus luteum
of rhesus monkeys at midluteal phase of the menstrual cycle.
Subpopulations of cells will be distinguished and separated by
multiparameter flow cytometry, based on differences in forward and
90 degrees light scatter (a function of cell size/shape and density
of organelles) and the binding of fluorescent-tagged hCG and
prostaglandins. Sorted groups of cells will be incubated in vitro
as acute suspensions to examine (a) their capacity to produce
progesterone, estrogens and prostaglandins (PGs) E2, F2 alpha, D2
and I2, and (b) their sensitivity to gonadotropic hormones (LH and
CG), various PGs and estrogens. Finally, different groups of cells
will be cultured individually or together to elucidate cell-to-cell
interactions which promote or inhibit steroidogenesis. Distinguishing the activities and regulatory mechanisms for luteal
cell subtypes within the monkey corpus luteum could revise
dramatically theories on the control of luteal function in
primates. The project would provide the framework for further
studies elucidating the origins, functions and changes in specific
cell types during the lifespan of the corpus luteum in the normal
menstrual cycle, throughout pregnancy and in situations associated
with luteal dysfunction.