PROLACTIN MODULATION OF THEOPHYLLINE INHIBITORY ACTION ON MATURATION OF BOVINE OOCYTE-CUMULUS COMPLEXES
IN VITRO
Yu. Lebedeva, O. S. Skotti, T. I. Kuzmina
All-Russian Research Institute of Farm Animal Genetics and Breeding, St. Petersburg-Pushkin;
e-mail: irledv@mail.ru
The comparative investigation of the individual and joint impact of prolactin (PRL, 50 ng/ml) and theophylline
(TP), a nonselective inhibitor of phosphodiesterases, on nuclear maturation of bovine oocytes and the expansion of
cumulus cells enclosing the oocytes was carried out using a model of in vitro culturing. It has been shown that TP
(5 mM) exerts a short-term inhibitory action on oocyte meiosis reinitiation and blocks it at diakinesis and
metaphase I stages as well as inhibits the cumulus expansion. The addition of PRL to the medium containing TP caused
the decrease in the rate of oocytes at diplotene stage after 6 h of culturing and the increase in the rate of oocytes
attained the closing stages of maturation after 24 h of culturing. Furthermore, PRL suppressed partly the inhibitory
impact of TP on the expansion of cumulus cells. The data obtained suggest the signal cascade induced by PRL in
bovine oocyte-cumulus complexes to be conpled with cAMP-dependent intracellular pathway.
Key words: prolactin, theophylline, cAMP, oocytes, cumulus cells, in vitro maturation, meiosis
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