R. Sudik et al., HUMAN FOLLICULAR-FLUID LEVELS OF ENDOTHELINS IN RELATION TO OOCYTE MATURITY STATUS, EXPERIMENTAL AND CLINICAL ENDOCRINOLOGY & DIABETES, 104(1), 1996, pp. 78-84
The levels of endothelins 1 and 2 (ET-1 and ET-2) have been examined i
n 415 follicular fluids of 57 women participating in the IVF-ET progra
mme in the University Women's Hospital, Marburg, in relation to the mo
rphological appearance (''maturity'') and fertilizability of harvested
oocytes as well as to the levels of inhibin, FSH, IGF-1, estradiol an
d progesterone. Follicular aspiration was done transvaginally in all p
atients after down regulation with nafareline and ovarian stimulation
using urofollitropin and menotropin. Ovulation was induced by hCG. ETs
were measured by RIA using commercial kits supplied by Peninsula Labo
ratories, Belmont, CA. For FF samples, ET-1 and ET-2 RIAs were revalid
ated. Immunoreactive ET-1 was detectable in all follicular samples, th
e average level being 18.5 +/- 11.8 pg/ml, ET-2 was present only in 67
.5% of the samples, the average level being 13.6 +/- 16.3 pg/ml. There
was no significant difference in the average levels of ET-1 in the fl
uids of small, medium and large follicles. However, there was a signif
icantly higher level of ET-2 in the fluids of medium compared to large
follicles and there was a negative correlation of the ET-2 levels to
the volume of the follicle (p < 0.01) which suggests that ET-2 could p
lay a role during the maturation of the ovarian follicles. Unlike ET-1
, the mean concentrations of ET-2 were significantly higher in the flu
ids with oocytes which could be fertilized and cleaved than in those w
ith oocytes which did not fertilize or cleave, thus indicating a role
for ET-2 in the process of oocyte maturation. No correlations of ET le
vels were found with the levels of inhibin, FSH, estradiol and progest
erone. However, ET-2 levels significantly correlated with the levels o
f IGF-1 (p < 0.001) indicating a possible synergistic effect of endoth
elins and IGF-system. In conclusion, this study is further evidence fo
r a physiological role of the ETs in the human ovary.