A morphologic and morphometric study of the mitochondria in several hepatoma cell lines and in isolated hepatocytes

On the Origin of ATP Synthesis in Cancer

ATP is required for mammalian cells to remain viable and to perform genetically programmed functions. Maintenance of the ΔG′_ATP hydrolysis of −56 kJ/mole is the endpoint of both genetic and metabolic processes required for life. Various anomalies in mitochondrial structure and function prevent maximal ATP synthesis through OxPhos in cancer cells. Little ATP synthesis would occur through glycolysis in cancer cells that express the dimeric form of pyruvate kinase M2. Mitochondrial substrate level phosphorylation (mSLP) in the glutamine-driven glutaminolysis pathway, substantiated by the succinate-CoA ligase reaction in the TCA cycle, can partially compensate for reduced ATP synthesis through both OxPhos and glycolysis. A protracted insufficiency of OxPhos coupled with elevated glycolysis and an auxiliary, fully operational mSLP, would cause a cell to enter its default state of unbridled proliferation with consequent dedifferentiation and apoptotic resistance, i.e., cancer. The simultaneous restriction of glucose and glutamine offers a therapeutic strategy for managing cancer.

Quantitative and qualitative changes in the mitochondria in hepatocytes during postnatal development of male rats

The volume density of mitochondria increases during postnatal development of the hepatocytes of male rats (test ages: 0 [birth], 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 14th, 21st, 28th day and 2nd, 3rd, 4th, 5th and 6th month) from 0.165 at birth to 0.236 on the 14th day, after which it decreases to 0.139 until the 6th month. At the same time the absolute volume of the mitochondria of the hepatocytes increases from 728.8 micrometer 3 at birth to 1225.5 micrometer 3 on the 14th day and reaches a maximum of 2102.3 micrometer 3 at the end of the 2nd month. The number of mitochondria per hepatocyte is 204 at birth. It increases continuously and reaches 2199 at the end of the 6th month. The volume of the average mitochondrion on the other hand diminishes during postnatal development from 3.83 micrometer 3 at birth to 0.64 micrometer 3 towards the end of the 6th month. Transverse divisions of mitochondria, budding of parts of mitochondria, autophagocytotic processes and degenerative changes can be observed throughout this period.