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Sex Differences in Calcium Regulatory Proteins in Immature Rainbow Trout ( Oncorhynchus mykiss )
Author(s) -
Rodnick Kenneth J,
Hicks Mary J,
Gambliel Herve A,
Olson Richard D
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a584
Subject(s) - rainbow trout , phospholamban , ryanodine receptor , endocrinology , calcium , medicine , chemistry , trout , ventricle , biology , fishery , fish <actinopterygii>
The purpose of this study was to determine whether immature male and female rainbow trout express different concentrations of Ca 2+ regulatory proteins in heart. Thus, we evaluated ventricular concentrations of phospholamban (PL), Ca‐ATPase of sarcoplasmic reticulum (SERCA2) and alpha 1C subunit of dihydropyridine receptor (DHPR). Individual male (N=5) and female (N=5) hearts (398 mg/ventricle) were homogenized in 8 ml of 50 mM N ‐tris(hydroxymethyl)methyl‐2‐aminoethanesulfonic acid (TES) buffered saline, pH 7.5. Following determination of protein concentrations (BCA assay) and Coomassie staining, 40 μg of protein/heart were run on SDS‐PAGE gels and then transferred to PVDF (hydrophobic polyvinylidene difluoride) membranes for Western blotting and then quantified by densitometry. Results showed that cardiac DHPR was not different between males and females (51,619 ± 7,952 vs. 55,440 ± 6,279, respectively). In contrast, male hearts had significantly higher levels (P<0.05, unpaired t‐test) of PL (93,215 ± 7,965 vs. 67,442 ± 6,011) and SERCA2 (52,546 ± 5,078 vs. 32,324 ± 3,908). Values are mean ± SEM, expressed in arbitrary units. These data support the observations that male trout cardiomyocytes store more calcium, while isolated cardiac preparations from males have significantly higher rest‐potentiated contractions and greater inotropism to caffeine than female preparations. Funded by NSF IOB‐517669