Dual regulation of the T-type Ca(2+) current by serum albumin and beta-estradiol in mammalian spermatogenic cells

• Published in: FEBS letters Vol. 475; no. 3; pp. 251 - 256
• Main Authors: Espinosa, F, López-González, I, Muñoz-Garay, C, Felix, R, De la Vega-Beltrán, J L, Kopf, G S, Visconti, P E, Darszon, A
• Format: Journal Article
• Language: English
• Published: England 23.06.2000
• Subjects: Animals; Calcium - metabolism; Calcium Channels, T-Type - metabolism; Estradiol - pharmacology; Ion Transport - drug effects; Male; Patch-Clamp Techniques; Serum Albumin - pharmacology; Spermatozoa - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(00)01688-4

This study provides evidence for a novel mechanism of voltage-gated Ca(2+) channel regulation in mammalian spermatogenic cells by two agents that affect sperm capacitation and the acrosome reaction (AR). Patch-clamp experiments demonstrated that serum albumin induced an increase in Ca(2+) T current density in a concentration-dependent manner, and significant shifts in the voltage dependence of both steady-state activation and inactivation of the channels. These actions were not related to the ability of albumin to remove cholesterol from the membrane. In contrast, beta-estradiol significantly inhibited Ca(2+) channel activity in a concentration-dependent and essentially voltage-independent fashion. In mature sperm this dual regulation may influence capacitation and/or the AR.