MESENCHYMAL-EPITHELIAL INTERACTIONS IN THE OVARIAN FOLLICLE INVOLVE KERATINOCYTE AND HEPATOCYTE GROWTH-FACTOR PRODUCTION BY THECAL CELLS AND THEIR ACTION ON GRANULOSA-CELLS
Ja. Parrott et al., MESENCHYMAL-EPITHELIAL INTERACTIONS IN THE OVARIAN FOLLICLE INVOLVE KERATINOCYTE AND HEPATOCYTE GROWTH-FACTOR PRODUCTION BY THECAL CELLS AND THEIR ACTION ON GRANULOSA-CELLS, Endocrinology, 135(2), 1994, pp. 569-575
Mesenchymal-epithelial cell interactions between thecal and granulosa
cells in bovine ovarian follicles were investigated. Experiments were
designed to examine the local production and action of two mesenchymal
(stromal)-derived growth factors, keratinocyte and hepatocyte growth
factors (KGF and HGF). Using reverse transcription-polymerase chain re
action, gene expression for KGF and HGF was detected in the mesenchyma
l-derived thecal cells, but not in the epithelial granulosa cells. The
bovine polymerase chain reaction products for KGF and HGF were sequen
ced and found to be similar to known mouse, rat, and human sequences.
The bovine KGF sequence was found to have a high degree of identity (8
6-95%) with the other species, whereas bovine HGF has a lesser degree
of identity (60-63%). Immunoprecipitation of radiolabeled thecal cell
secreted proteins with a KGF antibody demonstrated production of the 2
8-kilodalton (kDa) KGF protein. An immunoblot of thecal cell secreted
proteins with HGF antibodies detected the 87-kDa HGF as well as releva
nt 69- and 34-kDa subunits. Therefore, thecal cells were found to expr
ess the genes and secrete the proteins for KGF and HGF. Granulosa cell
s had no detectable KGF or HGF expression. Treatment with recombinant
KGF or HGF stimulated the proliferation of granulosa cells, but not th
ecal cells. Therefore, the actions of KGF and HGF in the ovarian folli
cle appear to be restricted to granulosa cells. The combined results i
ndicate that KGF and HGF are produced locally in the bovine ovarian fo
llicle by thecal cells, and that both of these growth factors can act
on granulosa cells to influence cell proliferation. These observations
demonstrate that KGF and HGF can mediate mesenchymal-epithelial cell
interactions between thecal and granulosa cells. The potential importa
nce that the mesenchymal derived thecal cells may have in ovarian foll
icle development is discussed.