Synergistic action of growth hormone and insulin-like growth factor I (IGF-I) on proliferation and estradiol secretion in porcine granulosa and theca cells cultured alone or in coculture.
The effect of growth hormone (GH) on insulin-like growth factor I (IGF-I) secretion and the effects of GH and IGF-I on [(3)H] thymidine incorporation and estradiol (E2) secretion by theca interna (Tc) and granulosa cells (Gc) cultured alone and in coculture were studied in cultured porcine follicular cells, prepared from small (SF), medium (MF) and large (LF) preovulatory follicles. We demonstrated that both Tc and Gc secrete IGF-I and that GH had no effect on IGF-I secretion by Tc but, increased IGF-I secretion by Gc isolated from SF and cultured alone or in coculture. IGF-I stimulated secretion of E2 by all cells, except in Tc derived from SF in which the effect was not statistically significant. The only stimulatory effect of concurrent treatment with GH on E2 secretion was noted in Tc derived from MF. IGF-I increased the [(3)H] thymidine incorporation in all Tc cells but GH did not augment this effect. In Gc, IGF-I stimulated [(3)H] thymidine incorporation in cells derived from SF and MF but not from LF. GH had no stimulatory effect except on Gc derived from LF and grown alone. The highest stimulatory effect was observed in SF. This was smaller in MF and no effect was noted in LF. In conclusion, our work shows that both Gc and Tc are sites of IGF-I production and for the first time shows the stimulatory role of IGF-I in proliferation of Tc cells derived from all types of follicles and augmentation of E2 secretion in Tc derived from MF and LF. The promotion of the mitogenic activity in Tc by IGF-I during all stages of follicular development suggests an important role for theca cells in follicular growth.
Kolodziejczyk
Jolanta
J
Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology, Jagiellonian University, Ingardena 6, 30-060 Kraków, Poland.
Gertler
Arieh
A
Leibovich
Haim
H
Rzasa
Janusz
J
Gregoraszczuk
Ewa Lucja
EL
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D018920:Coculture Techniques; D004247:DNA / Q000096:biosynthesis; D004357:Drug Synergism; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D006107:Granulosa Cells / Q000166:cytology / Q000502:physiology*; D013006:Growth Hormone / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D006080:Ovarian Follicle / Q000166:cytology; D013552:Swine; D013799:Theca Cells / Q000166:cytology / Q000502:physiology*; D014316:Tritium
D014316:Tritium; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone; D004247:DNA