Adenosine diphosphate and calcium stimulation of respiration in mitochondria from alloxan diabetic rats

✍ Scribed by Rita Anne Garrick; James C. Hall

• Publisher: John Wiley and Sons
• Year: 1974
• Tongue: English
• Weight: 605 KB
• Volume: 84
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1040840212

✦ Synopsis

Abstract

Liver mitochondria from normal and alloxan diabetic rats, isolated in 0.25 M sucrose, were assayed with an oxygen electrode for ADP/O and Ca^+2^/O ratios, respiratory ratio, and respiratory control index. Mitochondria were incubated with two substrates, succinate and β‐hydroxybutyrate; two types of ionic media, Na^+^ medium (Na^+^ the major monovalent cation) and K^+^ medium (K^+^ the major monovalent cation); and two respiratory stimulants, ADP (352 μM) and Ca^+2^ (187 μM). Significant differences between respiratory rates and ADP/O ratios were dependent upon the substrate and ionic medium employed. The results confirm previous studies which showed no alteration in ADP/O ratio but decreased State 3 respiratory rates under similar conditions of K^+^ medium with ADP stimulation in the diabetic. Furthermore, the State 3 respiration was prolonged compared to normal. Ca^+2^ stimulation was the same in normal and diabetic mitochondria in K^+^ medium. Studies in Na^+^ media revealed more significant differences in RCI's, respiratory rates, and ADP/O ratios that were substrate dependent as well as ion dependent. The results from these various studies can be accounted for by an hypothesis linking mitochondrial K^+^ interaction with alterations in the diabetic mitochondria.