Influence of sexual hormones on oxygen consumption in rats

Introduction:

Literature findings suggest that fluctuations of female sex hormones may change the maximum oxygen consumption (VO_{2 max}).

Objective:

To compare the VO_{2 max} among male rats (M, n = 8), female rats on ovulatory (OV, n=8) or non-ovulatory (NOV, n=8) phases of the estrous cycle and ovariectomized (OS, n=8).

Methods:

The evaluation of oxygen consumption was performed on a treadmill coupled with metabolic box.

Results:

At rest VO₂ was similar among groups. The M group had a higher VO_{2 max} compared to the NOV group, however showed similar values when compared to OV group. The VO_{2 max} was lower in the ovariectomized group (OS: 62±3 ml.kg-1.min-1) compared to other groups (M: 92±2; NOV: 77 ± 4; OV: 87 ± 3 ml.kg-1.min-1).

Conclusions:

These findings suggest that hormonal variation resulting from different phases of the estrous cycle and ovarian hormone deprivation can induce changes in maximal oxygen uptake in rats.

oxygen consumption; rats; sex differences; menopause