Progesterone triggers intracellular calcium wave by a catsper-independet mechanism in human sperm

SOSA CLAUDIA MARCELA; ARIAS RODOLFO JOSE; PAVAROTTI MARTIN; MAYORGA LUIS SEGUNDO; DE BLAS GERARDO ANDRES

Mar del Plata

Congreso; LI Reunión Anual de Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Previous works have shown that progesterone acts on CatSper calcium channels. These ion channels are found exclusively in the membrane of the sperm tail. Progesterone opens CatSper channels and triggers a fast increase in intracellular Ca2+. This ion is crucial for sperm functions, such as the regulation of capacitation, hyperactivation and acrosome reaction. The aim of this study was to investigate whether progesterone can trigger an intracellular calcium increase in absence of extracellular calcium. We used fluorescent calcium sensors in real time dynamic assays in single cell -with high speed and spatial resolution- and population measurements in a spectrofluorimeter. Capacitated human sperm were loaded with Fluo3-AM, then incubated in a calcium-free medium and treated with progesterone. We found that in the absence of extracellular Ca2+, progesterone induces a calcium increase that starts in the midpiece/neck region and propagates to the acrosome region. These findings indicate that progesterone can trigger the release of calcium from intracellular calcium stores by a CatSper independent mechanism.