Effects of GH and IGF-I on the in vitro maturation of mouse oocytes.
OBJECTIVE
A number of hormones and growth factors have been reported to affect the in vitro maturation of oocytes. Their exact effects on follicular growth and oocyte maturation and the mechanisms involved are still unclear. In the present study, we have investigated the effects of Growth Hormone (GH) and Insulin-like Growth Factor 1 (IGF-1) on the in vitro maturation of mouse oocytes.


METHODS
Immature preovulatory oocytes without cumulus cells (denuded), were obtained from 4- to 8-week old female mice and were cultured in Ham's F-10 medium. GH and IGF-1 were added separately or in combination in gradually increasing concentrations in the culture media, while medium-only containing samples were employed as controls. Oocyte development was assessed daily for three days and maturation was considered to be completed when the first polar body appeared.


RESULTS
In control samples, 44+/-3% (mean+/-SE) of denuded oocytes formed a polar body. The achieved maturation rate after the addition of either GH or IGF-1 or GH plus IGF-1 was significantly higher than in controls. The highest maturation rates were achieved after the addition of 0.2 microg/ml GH (76%+/-5%), 50 ng/ml IGF-1 (69%+/-5%) and a combination of 0.2 microg/ml GH plus 10 ng/ml IGF-1 (75%+/-5%).


CONCLUSIONS
The data suggest that GH and IGF-1, alone or in combination, affect mouse oocyte maturation significantly. The lack of a synergistic effect on oocyte cultures when both hormones were added indicates that both hormones act through the same signaling pathway.
Kiapekou
Erasmia
E
1st Endocrine Section, 1st Department of Obstetrics and Gynaecology, Alexandra Hospital, Athens University Medical School, Athens, Greece. nem10@panafonet.gr
Loutradis
Dimitris
D
Drakakis
Peter
P
Zapanti
Evangelia
E
Mastorakos
George
G
Antsaklis
Aristidis
A
D000704:Analysis of Variance; D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000166:cytology / Q000187:drug effects*; D009866:Oogenesis / Q000187:drug effects*; D010053:Ovary / Q000166:cytology; D011336:Probability; D012680:Sensitivity and Specificity
D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone