Mitochondrial Physiology Network 10.9: 18 (2005) - download pdf

Role of gender and caloric restriction in mitochondrial respiration-phosphorilation capacities and biogenesis in rat skeletal muscle.

Bartomeu Colom, MP Alcolea, A Valle, J Oliver, P Roca, FJ Garcia-Palmer

Grup de Metabolisme Energètic i Nutrició, Dept. Biología Fonamental i Ciències de la Salut, Institut Universitari d´Investigació en Ciències de la Salut (IUNICS), Universitat de les Illes Balears, Ctra Valldemossa s/n (07122), Palma de Mallorca, Spain. - vdbsbcp4@uib.es

    Previous work has shown the existence of a sexual dimorphism in the mechanisms in charge of the adaptation to food deprivation periods in rodents. Accordingly, females may have evolved adaptations to better withstand caloric restriction, a frequent condition in nature, probably because they are subjected to more severe selection pressures during time of food supply than males [1]. One of these mechanisms is the great ability of females to conserve energy in periods of food restriction, with their consequent higher energy efficiency [2,3]. Changes in this efficiency can be linked to changes in the necessary mechanisms to obtain sufficient energy, which are the mitochondrial oxidative-phosphorylation (OXPHOS) complexes.

    In this work, we studied the role of gender and caloric restriction in the modification of mitochondrial respiration-phosphorilation capacities and mitochondrial biogenesis in rat skeletal muscle. For this purpose, Wistar rats of both genders were subjected to a three months of 40 % caloric restriction diet and compared to control rats fed ad libitum. Skeletal muscle gastrocnemius were removed, and we measured the nuclear and mitochondrial DNA (mtDNA) contents, the enzymatic activities of mitochondrial respiratory chain complexes I, III, IV, and ATPase (OXPHOS system), as well as the expression and protein content of several genes involved in mtDNA replication, transcription, and mitochondrial function, such as peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factors 1 and 2 (NRF-1, NRF-2), mitochondrial transcription factor A (TFAM), mitochondrial single DNA binding protein (mtSSB) and cytochrome c oxidase subunits I and IV (COX I, COX IV). The results indicated that mitochondrial muscle biogenesis was not altered either by gender or by three months of caloric restriction diet. Besides, skeletal muscle of female rats had a higher mitochondrial respiratory chain machinery and phosphorylation capacity than males, which is not due to differences in mitochondrial mass, but due to a higher cellularity index.

     Supported by the Spanish Government (Fondo de Investigación Sanitaria, FIS PIO21339, del Ministerio de Sanidad y Consumo).

1.  Hoyenga KB, Hoyenga KT (1982) Gender and energy balance: sex differences in adaptations for feast and famine. Physiol. Behav. 28: 545-563.

2.  Hill JO, Talano CM, Nickel M, DiGirolamo M (1986) Energy utilization in food-restricted female rats. J. Nutr. 116: 2000-2012.

3. Valle A, Catala-Niell A, Colom B, Garcia-Palmer FJ, Oliver J, Roca P (2005) Sex-related differences in energy balance in response to caloric restriction. Am. J. Physiol. Endocrinol. Metab. (in press).