Effect of cAMP-related substances on selected rabbit reproductive parameters

Abstract

The aim of our study was to examine the effect of 3-isobutyl-1-methyl-xanthine (IBMX) and dibutyryl cyclic adenosine monophosphate (dbcAMP), stimulators of cAMP/protein kinase A-dependent intracellular signaling pathway, on reproductive function of gonadotropin-stimulated rabbit females. Ovarian cycle and ovulation in the control group were stimulated by PMSG (pregnant mare serum gonadotropin) 80IU/doe and after 72 hours with hCG (human chorionic gonadotropin) at 150 IU/doe. In the experimental group the females were stimulated with PMSG and hCG with the addition of either IBMX or dbcAMP at the dose of 50 µg/doe. In the first series of experiments, 18-19 hours after artificial insemination and ovulation the animals were killed, the pronuclear-stage eggs were flushed from the oviducts and cultured up to the blastocyst cell stage. Numbers of ovarian corpora lutea, ovulated oocytes, and oocyte-derived embryos reaching blastocyst stage were determined. In the second series of the experiments, all the animals were kept until parturition, when the conception rate and parturition rate, number of liveborn pups, stillborn pups and weaned pups were recorded. In vitro results show that both tested substances significantly increased female fertility parameters (number of corpora lutea, number of ovulated oocytes, number of oocyte-derived zygotes, embryos at morula stage and number of embryos at hatching blastocyst stage). The present result of in vivo studies show that both tested substances decreased female fertility parameters - conception rate, parturition rate and weaning rate compared to control, but they did not affect the stillborn pup rate. These observations confirm the involvement of cAMP/protein kinase A-dependent intracellular signaling pathway in control of rabbit reproduction.