Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2019742 | Prostaglandins & Other Lipid Mediators | 2010 | 6 Pages |
The aim of these studies was to evaluate of the relationship between luteal concentrations of oxytocin (OT), noradrenaline (NA), progesterone (P4), oxytocin receptors (OT-R) and β2-adrenoreceptors (β2-R) gene expression and their protein level throughout the estrous cycle in cattle. Corpora lutea (CL) collected during days 1–5, 6–10, 11–16 and 17–21 of the estrous cycle were used in these studies. Concentrations of P4, OT and NA were determined in tissue extracts. Gene expression and protein level for OT-R and β2-R were investigated by RT-PCR and Western blot, respectively. Luteal concentration of P4 was higher (P < 0.01) on days 6–10 and 11–16 than during days 1–5 and 17–20 of the estrous cycle. Concentration of OT was the highest on days 1–5 and 6–10 of the estrous cycle. This concentration decreased (P < 0.01) during days 11–16 reaching the lowest level (P < 0.001) on days 17–20 as opposed to days 1–10 of the estrous cycle. Expression of OT-R mRNA was lower on days 6–16 (P < 0.05) followed by its increase on days 17–20 as opposed to the expression observed on days 1–5. Expression of OT-R mRNA was negatively correlated (P < 0.05) with the profile of OT-R protein level. This latter parameter was the lowest on days 17–20 and 1–5, and the highest on days 6–10 and 11–16. Oxytocin concentration was negatively correlated (P < 0.05) with expression of OT-R mRNA and positively correlated (P < 0.001) with OT-R protein level. This protein level was only correlated with P4 (r = 0.59; P < 0.05). Concentration of OT was positively correlated with level of P4 (P < 0.001). Concentration of NA was the highest on days 1–5 of the estrous cycle, whereas it was similar or lower (P < 0.05) on days 6–21. Expression of mRNA for β2-R was the lowest on days 1–5 and was highly increased (P < 0.05) on days 6–16. The expression was the highest (P < 0.001) on days 17–21 compared to all others group of the estrous cycle. Protein level for β2-R was the highest on days 1–5 and decreased (P < 0.05) on days 6–10 and 11–16. The expression was the lowest on days 17–20 compared to the β2-R protein level in CL from all others stages of the estrous cycle. Protein level for β2-R was positively correlated (P < 0.05) with the OT concentration. Expression of mRNA for β2-R was negatively correlated (P < 0.001) with level of β2-R protein. No correlation was found between β2-R mRNA expression and NA concentration or between NA and P4 concentrations. Results presented in this study suggest an evident relationship between OT and NA and may play an important role in the regulation of luteal steroidogenesis during all stages of the estrous cycle.