Effect of Progesterone on Bovine Sperm Capacitation and Acrosome Reaction

Abstract

Progesterone (P) appears to stimulate sperm capacitation and/or induce the acrosome reaction (AR) in some species. In bovine, it is now well established that the BSP-A1/-A2 proteins (the major proteins of bovine seminal plasma) promote sperm capacitation. In this study, we investigated the effect of P on bovine sperm cholesterol efflux, capacitation, and the AR. Labeled bovine epididymal sperm were incubated (0-6 h) with different concentrations of P (0.01-10 microg/ml) in the presence or absence of BSP-A1/-A2 proteins (capacitating conditions). At different time intervals, aliquots of sperm were taken to determine the sperm cholesterol efflux, sperm capacitation (AR induced by lysophosphatidylcholine, lyso-PC), and sperm AR. The results show that the presence of P in the media did not affect the membrane cholesterol efflux potential of the BSP-A1/-A2 proteins. P alone did not stimulate the AR with or without lyso-PC unless the epididymal sperm were incubated in capacitating conditions (in the presence of BSP-A1/-A2). When washed ejaculated sperm were continuously incubated with P, the P did not stimulate AR. However, when ejaculated sperm were preincubated (6 h) with heparin (capacitation medium) and then incubated 15 min with P (2 microg/ml), the percentage of AR obtained was similar to that obtained with lyso-PC. The effect of P on sperm AR was concentration dependent with a maximum 2.2-fold increase at 2 microg/ml of P. These results demonstrate a potential role of P in bovine sperm AR but not in capacitation.

Fluorometric Study of Rabbit Sperm Head Membrane Phospholipid Asymmetry During Capacitation and Acrosome Reaction Using Annexin-v Fitc

“…epididymal sperm were previously incubated in capacitating conditions. However, when ejaculated sperm were preincubated (6 h) with capacitation medium A and then incubated 15 min with P (3.18 mg=ml), the percentage of AR obtained increased significantly (Table 2); these results are similar to those obtained in bovine sperm [27]. Calcium flux is induced specifically by progesterone in capacitated and uncapacitated sperm cells, whereas only …”

Prostasomes: extracellular vesicles from the prostate

“…However, while the acrosome reaction can take place at the zona pellucida surface, it is probably initiated even earlier under the influence of cumulus cells, the follicle wall derived epithelial cells that surround the recently ovulated oocyte in the oviduct (Jin et al 2011). Progesterone secreted by these cells (Therien & Manjunath 2003), coupled with the previously described transfer of progesterone receptors and other Ca 2C signalling tools by prostasomes (Park et al 2011), may be important factors in this process.…”

Binding patterns of seminal plasma plasma proteins on bovine epididymal and ejaculated sperm membrane

“…BSP A3 is expressed only in the AGF (Thérien and Manjunath, 2003), PGDS and transferrin only in the bovine CEF (Moura et al, 2007ab), while albumin and nucleobindin are components of both secretions. The present study shows evidence that BSP A3, PGDS and nucleobindin physically interact with sperm, either epididymal and/or ejaculated sperm.…”