Related Experiment Video
Updated: Jun 14, 2026
Application of Dixon's Up-and-Down Design to Estimate the Minimum Alveolar Concentration of Sevoflurane in Rats with Refined Movement Classification
Published on: July 25, 2025
Progesterone decreases sevoflurane requirement in male mice: a dose-response study
T Shimizu1, S Inomata, M Tanaka
1Department of Anesthesiology and Critical Care Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki 305-8575, Japan. taksmz@md.tsukuba.ac.jp
Background:
Progesterone has long been known to have central effects, by reduced anaesthetic requirements as measured by minimum alveolar concentration (MAC) in various settings. However, other studies have contradicted these findings. Therefore, we compared the effect of progesterone on anaesthetic requirements in a mouse model.
Methods:
Male C57BL/6 mice were treated with either progesterone (37.5 or 75 mg kg(-1)) or the olive oil vehicle, 1 h before each experiment. Animals were placed in a revolving cylinder (4 rev min(-1)) and supplied with oxygen and stepwise increasing concentrations of sevoflurane. The number of complete rollovers during revolution of the chamber was counted as a measure of anaesthetic requirement.
Results:
S.C. administration of progesterone 75 mg kg(-1) significantly reduced sevoflurane requirement (P<0.0001). Progesterone 37.5 mg kg(-1) did not change sevoflurane requirement.
Conclusions:
We conclude that administration of exogenous progesterone injection at higher concentrations decreases anaesthetic requirement as defined by rolling response.
