The possible role of intracellular polyamines in mitochondrial metabolic regulation.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to R H Rochelle.
Explore the source record for details and available documents.
Studies were made of polyamine and Mg++ effects on rat liver mitochondrial alpha ketoglutarate oxidase (alphaKGO) and succinoxidase (SO). High spermidine levels suppress S3 and S4 of alphaKGO at 0.6-1.17 mM Mg++: some combinations of it and Mg++ increase the respiratory control ratio (RCR). Spermine suppresses S4 of alphaKGO and increases the RCR but suppresses the RCR of SO at high levels. In heat-acclimated (HA) animals in which we have studied only spermine effects on alphaKGO, RCRs of HA rats are greatly increased compared to those of controls.
1. Increasing the Mg2+ concentration results in a depression of succinoxidase-linked state 3 respiration of liver mitochondria from both control and cold-acclimated rats and hamsters. 2. It appears that in the cold-acclimated hamster, liver mitochondrial respiration is more sensitive to changes in Mg2+ levels than that of the rat.
The isometric strength of four trained subjects was unaltered by changes in posture. But the endurance of an isometric contraction held to fatigue at 25 and 40% of the maximum voluntary contraction (MVC) was 20% greater in the sitting than in the recumbent posture. This difference was abolished when the exercise was performed with the arm's circulation arrested. At rest, the blood flow through the forearm was greater when the subjects were in the recumbent than in the sitting position but the reverse was true during isometric contractions. In these two postures, there was no difference in the right atrial pressure during the contraction, suggesting that the low-pressure baroreceptors are not responsible for the differences in blood flow during exercise. To date no mechanism is available to explain these observations.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.