[Sites of prolactin inhibition on gonadotropin-induced estrogen production in cultured rat granulosa cells].
We studied the sites of prolactin inhibition upon FSH-iniduced ovarian steroidogenesis and the ability of prolactin (Prl) to inhibit the synthesis of estradiol and cAMP accumulation under the stimulation of FSH or cAMP-dependent activators. The participation of other signal pathways such as PKC and Gi proteins on the inhibitory actions of Prl was also investigated using calfostine C and pertusis toxin as inhibitors. Results showed a dose-dependent prolactin decrease in FSH-induced estradiol and cAMP production prior and after the generation of the cyclic nucleotide by a mechanisn involving the catalytic subunit of adeniyl cyclase and/or through activation of PKC or by the interaction with pertusin toxin-sensitive G proteins. Our results suggest a mechanism by which G protein-coupled receptors are linked with those coupled with tyrosine kinase through the involvement of a Gi protein mediated mechanism.
Larrea
Fernando
F
Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico, DF, Mexico. larrea@innsz.mx
Sánchez-González
Sergio
S
García-Becerra
Rocío
R
Méndeza
Isabel
I
D000262:Adenylyl Cyclases / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D002384:Catalysis; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004789:Enzyme Activation; D004958:Estradiol / Q000096:biosynthesis*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D019204:GTP-Binding Proteins; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D009281:Naphthalenes / Q000494:pharmacology; D037342:Pertussis Toxin / Q000494:pharmacology; D011388:Prolactin / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011962:Receptors, FSH / Q000378:metabolism; D015398:Signal Transduction; D013268:Stimulation, Chemical
D009281:Naphthalenes; D011962:Receptors, FSH; D004958:Estradiol; D011388:Prolactin; D005640:Follicle Stimulating Hormone; D000242:Cyclic AMP; D037342:Pertussis Toxin; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; C058819:calphostin C