[Reduction of the functional activity of the calcium pump of the sarcoplasmic reticulum of skeletal muscles in response to cold].

Fragments of sarcoplasmic reticulum (SR) from the white skeletal muscles of rat in cooling (1.5 day; -9 to +2 degrees C) revealed a decreased activity of the Ca2+-pump and rate of Ca2+ accumulation. The SR from rats adapted to cold for 2 and 4 weeks, revealed the same decreased functional ability. The Ca/ATP ratio was unchanged in all experiments.