Calcium content of mitochondria and endoplasmic reticulum in liver frozen rapidly in vivo

摘要: The recognition that the endoplasmic reticulum (ER), rather than mitochondria, is main organelle regulating cytoplasmic Ca2+ concentration in non-muscle cells1,2 supports notion an alternative physiological role of mitochondrial Ca transport3–5 modulation Ca-sensitive enzymes through small (micromolar) fluctuations matrix (refs 1,5–7). latter mechanism could operate only if were low, as it muscle and retinal rods8,9, below levels saturating regulated enzymes5. In contrast, ER serves intracellular store, its content would be expected to high. view major metabolic function liver, question whether hepatic regulates metabolism particularly important, but range concentrations reported for isolated liver mitochondria too wide10–12 provide a conclusive answer. Therefore, we have used electron probe X-ray microanalysis (EPMA) measure subcellular distribution snap-frozen vivo, report here store Ca, while low compatible with regulation enzymes.