Skeletal Muscle of Female Rats Exhibit Higher Mitochondrial Mass and Oxidative-Phosphorylative Capacities Compared to Males

Abstract

The effect of gender and caloric restriction on mitochondrial content and oxidative-phosphorylative capacities has been investigated in rat gastrocnemius muscle. Muscle protein, mitochondrial protein and DNA contents, enzymatic activities of mitochondrial oxidative and phosphorylative system, mitochondrial antioxidant enzymes, protein levels of complex IV (subunit I and IV) and ATPase, and the gene and protein expression of mitochondrial transcription factor A (TFAM), involved in mitochondrial replication and transcription, were measured in rats of both genders fed ad libitum and subjected to three months of 40% caloric restriction. Compared to males, gastrocnemius muscle of female rats showed higher mitochondrial DNA and protein contents, TFAM protein level, oxidative and phosphorylative machinery and activities, and glutathione peroxidase activity. In conclusion, the present data show a clear gender dimorphism in rat muscle mitochondrial features, which could explain the higher facility of females to adapt to altered metabolic energy situations.

Estradiol stimulates mitochondrial biogenesis and adiponectin expression in skeletal muscle

“…These results support a role of E 2 in the sexual dimorphism in rat skeletal muscle that we have previously reported, whereby female rats show higher mitochondrial mass, greater oxidative capacity, and also a better antioxidant response than their male counterparts (Colom et al 2007a, Gó mez-Pérez et al 2008, 2012. Furthermore, we demonstrate that ovarian hormones play a relevant role in adiponectin synthesis in skeletal muscle, and that E 2 could be a key effector in the stimulation of skeletal muscle adiponectin sensitivity.…”

“…Previous studies have reported that skeletal muscle of female rats shows greater mitochondrial differentiation and content accompanied by a higher OXPHOS capacity and better antioxidant response than that of males, which could explain the greater capacity of females to adapt to altered metabolic energy situations (Colom et al 2007a, Gó mez-Pé rez et al 2012. In addition, this sexual Tfam, mitochondrial transcription factor A; Nrf1, nuclear respiratory factor 1; Sirt1 and 3, sirtuin 1 and 3; MFN1 and 2, mitofusin 1 and 2; OPA1, optic atrophy protein 1; DRP1, dynamin-related protein 1.…”

“…As skeletal muscle from female rats exhibits greater mitochondrial mass, antioxidant protection, and oxidative-phosphorylative capacities than that from males (Colom et al 2007a, Català-Niell et al 2008, Gó mez-Pérez et al 2008, and E 2 has been shown to play a role in mitochondrial modulation in other tissues (Mattson et al 1997, Chen et al 1999, Rodríguez-Cuenca et al 2007, Moreira et al 2011, Nadal-Casellas et al 2011b, Amengual-Cladera et al 2012a, the aim of the present study was to elucidate the role of sex hormones in these differences, as well as their relationship with adiponectin production in skeletal muscle. This was accomplished by using a model of ovariectomized (OVX) rats to test the effects of a decrease in ovarian hormone levels and of E 2 replacement, combined with in vitro experiments with L6E9 myotubes, which were treated with E 2 , progesterone (Pg), and testosterone.…”

“…Sexual dimorphism in mitochondrial functionality has been described in many rat tissues such as liver, adipose tissue, brain, and skeletal muscle (Colom et al 2007a,b, Valle et al 2007a,b, Gó mez-Pérez et al 2008, 2012 with morphological differences consisting of larger mitochondria with greater cristae size and density. Oxidative stress status associated with physiopathological situations such as caloric restriction, high-fat-diet feeding, or aging, also shows sexual dimorphism, as female rats show lower oxidative damage than males, a fact that has been related to their higher antioxidant defences (Colom et al 2007b, Valle et al 2007b, Gó mez-Pérez et al 2008, Viña et al 2011, Amengual-Cladera et al 2012b.…”

Gender dimorphism in the exercise-naïve murine skeletal muscle proteome

“…Mitochondrial proteins did not comprise more than a third of total proteins identified, and did not show a blanket expression increase in one gender, leaving no evidence of a greater mitochondrial concentration in females. While females are thought to have a greater mitochondrial density than males [11], these studies use muscle tissue that has been metabolically challenged. Fig.…”