Characterization and expression of different pituitary adenylate cyclase-activating polypeptide/vasoactive intestinal polypeptide receptors in rat ovarian follicles.
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a bioactive peptide transiently expressed in preovulatory follicles. PACAP acts by interacting with three types of PACAP receptors. PACAP type I receptor (PAC(1)-R), which binds specifically to both PACAPs and vasoactive intestinal polypeptide (VIP), although with lower affinity, and two VIP receptors, VPAC(1)-R and VPAC(2)-R, which bind to PACAP and VIP with equal affinity. In the present study, we showed the expression of all three receptors in whole ovaries obtained from juvenile and gonadotropin-treated immature rats. A more detailed analysis on cells from preovulatory follicles showed that PAC(1)-R and VPAC(2)-R were expressed in granulosa cells, whereas only VIP receptors were expressed in theca/interstitial (TI) cells and fully grown oocytes presented only PAC(1)-R. The distribution of the VIP receptors was confirmed by immunofluorescence. HCG treatment induced stimulation of PAC(1)-R in granulosa cells and VPAC(2)-R in TI cells. The presence of functional PACAP/VIP receptors was also supported by metabolic studies. We further evaluated the presence of PACAP and VIP receptors by testing the effect of these peptides on apoptosis in granulosa cells cultured, isolated or in whole follicles. Treatment of follicles with PACAP and VIP dose-dependently inhibited apoptosis, while only PACAP significantly inhibited isolated granulosa cells. These results demonstrate a different expression of PACAP/VIP receptors in the various follicle compartments and suggest a possible role for PACAP and VIP on granulosa and TI cells, both during follicle development and ovulation.
Vaccari
Sergio
S
Department of Histology and Medical Embryology, University of Rome La Sapienza, Via A. Scarpa, 14, 00161 Rome, Italy.
Latini
Stefania
S
Barberi
Marzia
M
Teti
Anna
A
Stefanini
Mario
M
Canipari
Rita
R
D000818:Animals; D002118:Calcium / Q000032:analysis; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D000242:Cyclic AMP / Q000032:analysis / Q000378:metabolism; D003593:Cytoplasm / Q000737:chemistry; D017931:DNA Primers; D004305:Dose-Response Relationship, Drug; D005260:Female; D005455:Fluorescent Antibody Technique; D006107:Granulosa Cells / Q000737:chemistry; D009865:Oocytes / Q000737:chemistry; D006080:Ovarian Follicle / Q000737:chemistry* / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D018005:Receptors, Vasoactive Intestinal Peptide / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D051239:Receptors, Vasoactive Intestinal Peptide, Type II / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013268:Stimulation, Chemical; D013799:Theca Cells / Q000737:chemistry; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D006063:Chorionic Gonadotropin; D017931:DNA Primers; D010716:Phosphatidylinositols; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D018005:Receptors, Vasoactive Intestinal Peptide; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D002118:Calcium