Fig. 2.

Medroxyprogesterone acetate has no effect on brain mitochondrial respiratory activity alone or in combination with E2. Mitochondrial oxygen consumption ± in vivo E2 (30 μg/kg), MPA (120 μg/kg), E2+MPA (30 μg/kg + 120 μg/kg), or corn oil vehicle control (OVX). Ovary-intact (shamOVX) rats served as a positive control and were selected on the morning after estrus by vaginal cytology. Oxygen consumption measurements of isolated rat brain mitochondria were performed using MitoExpress A65N phosphorescent oxygen sensitive probe (Luxcel Biosciences, Cork). Isolated mitochondria were energized by addition of l-malate (5 mm) and l-glutamate (5 mm) as substrates. ADP (410 μm) was added to stimulate state 3 respiration, and rates were compared with unstimulated ADP-null, representing basal state 2 respiration. The traces are representative of five separate experiments. Data are expressed as a percent change in mitochondrial RCR (state 3/state 2) relative to OVX. The data represents mean ± sem of five separate experiments. *, P < 0.05 compared with OVX (n = 5).