Age and breed related levels of cyclic nucleotides in the avian reproductive tract

In avian species follicle selection and final growth and differentiation represents a complex physiological process for which the potential role of cyclic nucleotides has so far not been identified in detail. Therefore, follicles of different developmental stages and samples from the infundibulum, magnum and isthmus of the reproductive tract were taken from growing hens at different ages for measuring the concentrations of 3’,5’-cAMP and3’,5’-cGMP. The samples were taken within 5 minutes after slaughter from different genetic lines of hens, frozen in liquid nitrogen and kept at -85°C until analysis. The concentrations of cyclic nucleotides were measured by liquid chromatography-coupled mass spectrometry (LC-MS/MS). Expression of PKG1, PKG2, selected PDE isoforms (PDE3A, 3B, 5A and 9A) and guanylyl cyclases (GUCY1B3 and GUCY2C) were analysed by qRT-PCR analysis in the follicles. Strong expression of PKG1, PDE3A and 5A was detectable. No difference was found between the follicles of different sizes. Irrespective of the genetic background of the hens concentrations of 3’,5’-cAMP decreased with increasing follicle diameter whereas the concentrations 3’,5’-cGMP increased. Constant 3’,5’-cAMP levels were measured in samples from the infundibulum, magnum and isthmus. 3’,5’-cGMP concentrations in these segments were close to the level of detectability. No significant age effects could be detected.