Effects of testosterone on cardiomyocyte calcium homeostasis and contractile function in female rats.

Abstract:

:The role of testosterone (T) in the regulation of cardiovascular function in females is not well understood. Our goal was to examine the effect of T on cardiomyocyte biology by measuring sarcomere shortening/relaxation and intracellular calcium cycling in adult female Sprague-Dawley rats. The rats were divided into the following four groups: (1) sham operated; (2) ovariectomized (OVX); (3) OVX plus T; and (4) OVX + T plus an aromatase inhibitor (AI). The final group was added to rule out effects from bioconversion of T to oestradiol. Sarcomere/calcium dynamics were measured after 4 weeks at 2 and 6 Hz, then at 6 Hz following exposure to 300 nm isoprenaline. Additionally, the acute (i.e. non-genomic) effects of T were evaluated in sham-operated and OVX + T + AI rats. There were no group differences, nor was there evidence for an effect of T on frequency or isoprenaline response. Additionally, there were no findings to indicate an acute, non-genomic T effect. Moreover, the relative α- and β-myosin heavy chain isoform complement was unchanged by OVX or T replacement. Our results argue against acute or chronic effects of T on cardiomyocyte shortening dynamics, calcium cycling or myosin heavy chain expression, arguing against any direct effect of T on cardiomyocyte function in adult females.

journal_name

Exp Physiol

journal_title

Experimental physiology

authors

Beesley RD,Palmer BM,Casson PR,Toth MJ

doi

10.1113/expphysiol.2012.067009

subject

Has Abstract

pub_date

2013-01-01 00:00:00

pages

161-71

issue

1

eissn

0958-0670

issn

1469-445X

pii

expphysiol.2012.067009

journal_volume

98

pub_type

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