RECOMBINANT LUTEINIZING-HORMONE AS A SURVIVAL AND DIFFERENTIATION FACTOR INCREASES OOCYTE MATURATION IN RECOMBINANT FOLLICLE-STIMULATING HORMONE-SUPPLEMENTED MOUSE PREANTRAL FOLLICLE CULTURE
R. Cortvrindt et al., RECOMBINANT LUTEINIZING-HORMONE AS A SURVIVAL AND DIFFERENTIATION FACTOR INCREASES OOCYTE MATURATION IN RECOMBINANT FOLLICLE-STIMULATING HORMONE-SUPPLEMENTED MOUSE PREANTRAL FOLLICLE CULTURE, Human reproduction, 13(5), 1998, pp. 1292-1302
The effects of recombinant luteinizing hormone (rLH) and recombinant f
ollicle stimulating hormone (rFSH) both separately and together were a
nalysed on the in-vitro maturation of a well-defined class of mouse ea
rly preantral follicles, Metaphase-II (MII) oocytes were only obtained
when rLH or rFSH or a combination of both hormones was added to a sta
ndard rich culture medium at constant doses throughout the culture per
iod. Without gonadotrophins only 8% of the follicles reached day 12 of
culture. Follicle survival was optimal (between 90 and 100%) when rFS
H was used; significantly fewer follicles were kept intact when rLH wa
s added as the only supplement (54%; P < 0.001), Theca cells played a
fundamental role in follicle survival when rLH was the only supplement
. Presence of rLH significantly influenced the formation of antral-lik
e cavities: on day 12, 59% of follicles cultured with rLH + rFSH had a
large cavity, as compared with only 21% in cultures with rFSH only (P
< 0.0001), The rHCG stimulated germinal vesicle breakdown rate from t
he different gonadotrophin-supplemented cultures on day 12 was not sig
nificantly different (FSH: 89%; LH: 70%; FSH/LH: 83%), However, additi
on of rLH to rFSH did significantly improve (P < 0.05) the completion
of the first meiotic division up to the MII stage (FSH: 46%; LH: 39%;
FSH/LH: 76%), Interfollicle differences in steroid production were ver
y large and depended on the presence of theca cells and on the kind of
gonadotrophin supplemented. Without theca cells, oestrogen concentrat
ions in rFSH-supplemented cultures were 100 times lower than their the
ca-containing counterparts during the entire culture period. From cult
ure day 9 onwards most conditioned media had increased basal progester
one concentrations. This study points up the in-vitro role of LH on th
e differentiation of follicle-like structures and the oocyte's meiotic
maturation and suggests an important role for theca cells in providin
g modulators of in-vitro gonadotrophin action.