Effect of pituitary adenylate cyclase-activating peptide on meiotic maturation in follicle-enclosed, cumulus-enclosed, and denuded rat oocytes.
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a novel bioactive peptide isolated from ovine hypothalamus. Recently, its presence and action have been demonstrated also in peripheral tissues such as testis and ovary. On the basis of sequence similarity, PACAP is included in the vasoactive intestinal peptide (VIP)/glucagon/secretin/growth hormone-releasing factor (GRF) family of neuropeptides. Because both VIP and GRF stimulate oocyte maturation in the rat ovary, we wanted to evaluate whether PACAP also could influence this process. Granulosa cells and follicle-enclosed, cumulus-enclosed, and denuded oocytes were obtained from immature eCG-treated rats. The addition of PACAP-38 significantly accelerated meiotic maturation in follicle- and cumulus-enclosed oocytes from treated rats and in follicle enclosed-oocytes from immature untreated rats, while VIP was effective only on follicle-enclosed oocytes. Interestingly, when used on denuded oocytes, PACAP was able to directly affect the meiotic process. In fact, the neuropeptide delayed oocyte maturation by maintaining elevated levels of intracellular cAMP. Our results clearly demonstrate an involvement of PACAP in oocyte meiotic maturation. Furthermore, for the first time, a direct effect of a peptide on the oocytes has been shown. Moreover, the differences in the action of PACAP and VIP on granulosa cells and oocytes suggest the presence of PACAP type I receptors on both cell types. Our results, along with the data demonstrating the presence of the peptide in the ovary, strongly suggest a potential relevance of PACAP in ovarian physiology.
Apa
R
R
Istituto di Ginecologia ed Ostetricia, Università Cattolica S. Cuore, Roma, Italy.
Lanzone
A
A
Mastrandrea
M
M
Miceli
F
F
Macchione
E
E
Fulghesu
A M
AM
Caruso
A
A
Canipari
R
R
D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism; D008540:Meiosis / Q000187:drug effects*; D009479:Neuropeptides / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism; D006080:Ovarian Follicle / Q000378:metabolism / Q000502:physiology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051381:Rats; D017207:Rats, Sprague-Dawley; D013268:Stimulation, Chemical; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide; D005640:Follicle Stimulating Hormone; D000242:Cyclic AMP