Differential effects of insulin-like growth factor-I and gonadotropins on the proliferative activity of two subgroups of granulosa cells: cumulus oophorus and mural granulosa cells.
OBJECTIVE
To evaluate the physiological role of insulin-like growth factor-I (IGFI) and its interaction with gonadotropins in cell replication of two types of granulosa cells (cumulus oophorus, CC) and mural granulosa cells (MGC).


METHODS
Controlled randomized study of the action and interaction of gonadotropins and IGFI on granulosa cell replication in the rat.


METHODS
A university reproductive biology laboratory.


METHODS
The study examined the in vivo treatment with gonadotropins or an analogue of IGFI, long Arg3-insulin-like growth factor (LR3-IGFI), which does not bind to IGFI-binding proteins.


METHODS
Granulosa cell replication was evaluated by the use of 3H-thymidine incorporation.


RESULTS
It was noted that the CC replicate much faster than the MGC. These two types of granulosa cells have very different dose response curves to IGFI. Differential responses were seen in animal cells exposed to long Arg3-insulin-like growth factor in vivo and then exposed to FSH and LH in vitro.


CONCLUSIONS
Although murine granulosa cells show proliferative activity when they are exposed to IGFI, the two types, CC and MGC, respond differently. IGFI is not the sole mediator of the action of FSH, and these two chemicals may act independently or in concert.
Khamsi
F
F
Toronto Fertility Sterility Institute, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada. tfs@aaa-tfsi.com
Roberge
S
S
D000818:Animals; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D006063:Chorionic Gonadotropin / Q000494:pharmacology* / Q000502:physiology; D004054:Diethylstilbestrol / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000502:physiology*; D007986:Luteinizing Hormone / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D013552:Swine
D006063:Chorionic Gonadotropin; C084339:LR(3)IGF-I; D007334:Insulin-Like Growth Factor I; D004054:Diethylstilbestrol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone