title: Investigation of testosterone-mediated non-transcriptional inhibition of Ca2+in vascular smooth muscle cells.
abstract: The aim of the present study was to observe the effect of short-term testosterone treatment on Ca2+in vascular smooth muscle cells (VSMCs) of male rats. Cells were loaded with the Ca2+-sensitive fluorescent indicator Fura-2 and intracellular Ca2+signals of VSMCs were measured using a Nikon TE2000-E live cell imaging workstation. The baseline level of cytosolic Ca2+concentration ([Ca2+]i) in resting state VSMCs was ~100 nmol/l. Testosterone alone led to a slow increase in [Ca2+]i, but there was no significant difference compared with the ethanol vehicle control. When VSMCs were stimulated with a high-potassium solution (containing 42 mmol/l of K+), [Ca2+]irose rapidly and remained at a high plateau level. Short-term treatment using physiological (40 nmol/l) or supraphysiological (4 µmol/l) levels of testosterone at either the plateau phase or the pretreatment stage could significantly inhibit the [Ca2+]iincrease induced by high-potassium solutions. Testosterone coupled to bovine serum albumin also had a similar effect and repetitive testosterone interventions over a short time-frame led to inhibition. Testosterone has a non-transcriptional inhibition effect on the [Ca2+]iof VSMCs and acts with the cell membranes of VSMCs to inhibit voltage-gated Ca2+channel-mediated Ca2+influx, which may be one of the mechanisms underlying testosterone-mediated vasodilation.
authors.affiliation: Department of Ultrasound, Zhongda Hospital, Southeast University, Nanjing, Jiangsu 210009, P.R. China.
authors.forename: Zhongqian
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Department of Cardiology, Jinling Hospital, Nanjing, Jiangsu 210002, P.R. China.
authors.forename: Rui
authors.initials: R
authors.lastname: Ma
authors.affiliation: Department of Cardiology, Jinling Hospital, Nanjing, Jiangsu 210002, P.R. China.
authors.forename: Jianbin
authors.initials: J
authors.lastname: Gong
keywords: androgen; blood vessel; intracellular free Ca2+; muscle; non-transcriptional; smooth; testosterone