Metabolic and Hormonal Changes Associated with Vitellogenesis in Salvator merianae Lizards

Mitochondrial function in skeletal muscle contributes to reproductive endothermy in tegu lizards (Salvator merianae)

“…The reproduction phase of tegus is characterized by plasma peaks of sexual hormones in males (testosterone) and females (estradiol and progesterone), as well as hormones involved in energy expenditure and mobilization from reserves, such as thyroid hormones (predominantly in females) and glucocorticoids (in both sexes) 6,10,40,41 . Sex hormones are known to induce muscle hypertrophy, 47–49 and these hormone peaks coincide with the observed increase in lean mass during spring (Carabolante, Bicego, personal communication), which may be associated with a greater abundance of mitochondria.…”

“…The higher muscle thermogenesis per se during spring could favor the peak of locomotor activity and reproductive behaviors (mating, nest building), as well as the regrowth of gonads for gametogenesis and folliculogenesis and vitelogenesis for egg production. 6,9,40,41 This is particularly important, considering that all of these changes occur relatively fast after the motionless and minimum metabolism phase of about 3 months of hibernation.…”

“…This seasonal response was entirely independent of ambient temperature influence because, in both seasons, the tegus were maintained at 25°C for a week prior to muscle sampling, the same temperature at which the permeabilized fibers were analyzed inside the oxygraph. The higher muscle thermogenesis per se during spring could favor the peak of locomotor activity and reproductive behaviors (mating, nest building), as well as the regrowth of gonads for gametogenesis and folliculogenesis and vitelogenesis for egg production 6,9,40,41 . This is particularly important, considering that all of these changes occur relatively fast after the motionless and minimum metabolism phase of about 3 months of hibernation.…”