INTERACTION OF SIGNAL CASCADES INDUCED BY CAMP AND PROLACTIN IN BOVINE OOCYTE-CUMULUS COMPLEXES
I. Yu. Lebedeva,1, 2, * G. N. Singina,1 N. A. Volkova,1
A. N. Mormishev,1 A. K. Golubev,2 N. A. Zinovieva 1
1 All-Russian State Research Institute of Animal Breeding, Podolsk, and
2 Department of Animal Genetics, Breeding and Biotechnology, St. Petersburg State Agrarian University;
* e-mail: irledv@mail.ru
Prolactin (PRL) is one of the pituitary hormones participating in the control of mammalian folliculo- and oogenesis. In the present study, the joint
effect of PRL (50 ng/ml) and dibutyryl cAMP (dbcAMP, 1 mM) on oocyte maturation and the morphologic-functional state of surrounding cumulus
cells was investigated in vitro. It has been shown that PRL totally suppresses the braking impact of dbcAMP on meiosis reinitiation and the completion
of oocyte nuclear maturation. Furthermore, PRL partly inhibited cumulus expansion induced by dbcAMP, although it exerted the opposite effect in the
control medium. In the presence of PRL, the inhibitory impact of dbcAMP on the proliferative activity of cumulus cells and on the PRL-elicited braking
of destructive processes in the cells has been found. In cumulus cells, mRNA expression of PRL receptor long isoform was revealed by the RT-PCR
method. The data obtained suggest an interaction of signal cascades induced by PRL and cAMP in bovine oocyte-cumulus complexes, with the coupling
site of these cascades in oocytes being apparently different from that in cumulus cells.
Key words: prolactin, cAMP, oocytes, cumulus cells, in vitro maturation, meiosis
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