Stimulation of glycolysis by imidazole

The reversibility of cancer: the relevance of cyclic AMP, calcium, essential fatty acids and prostaglandin E1

Transformed cells in culture can be normalised (made to undergo reverse transformation) by exposure to cyclic AMP, prostaglandin (PG) E1 and certain drugs. One of these drugs, thioproline, has been successfully used in treating human cancer. All cancer cells have a number of common characteristics: they exhibit aerobic glycolysis, they fail to show feedback regulation of cholesterol biosynthesis, they do not regulate cytoplasmic calcium levels normally and they produce excessive amounts of 2 series PGs. It has been known since 1975 that transformed cells cannot make PGE1 because of loss of the delta-6-desaturase enzyme which converts linoleic acid to gamma-linolenic acid. There is evidence that PGE1 acting in concert with thromboxane A2 has effects which make it able to reverse all the metabolic abnormalities common to all cancer cells. It is therefore argued that loss of the ability to make PGE1 and/or thromboxane A2 may be the critical step in malignant change in many forms of cancer. Restoration of normal PGE1 synthesis by providing gamma-linolenic or dihomogammal inolenic acids which will by-pass the blocked desaturase, whould be of value in normalising malignant cells and reversing cancer growth. Since this approach is completely non-toxic it is here seriously suggested that it might be used as a first step in treatment of those cancers where current evidence suggests that delay in the administration of orthodox treatment is unlikely to affect prognosis.

A defect in thromboxane A2 synthesis may be a factor predisposing to cancer

A failure of thromboxane (TX) A2 synthesis may be a factor in cancer. Such a loss could explain the susceptibility to mutation, the excess prostaglandin production, the glycolytic mode of metabolism and the deranged calcium pumping characteristic of cancers. Ionising radiation and phorbols both have actions similar to inhibitors of TXA2 synthesis whereas colchicine and oxygen have actions consistent with stimulation of TXA2 synthesis. The concept accounts logically for hitherto unexplained features of cancer and suggests new strategies for the prevention and treatment of cancer.

Effect of imidazole on renal gluconeogenesis

The metabolic effects of imidazole were tested in rat renal cortex. Imidazole enhanced the activity of renal cortical phosphodiesterase in vitro. Imidazole inhibited glucose production in a dose-dependent fashion from a variety of substrates in the gluconeogenic pathway proximal to the triose phsophates. The stimulation in renal gluconeogenesis resulting from isoproterenol and parathyroid hormone was inhibited by imidazole. These changes correlated with an inhibition of the augmented levels of renal cortical cyclic AMP levels produced by these hormones. These studies indicate that imidazole is an effective activator of phosphodiesterase in intact renal cells and lend further support to the suggestion that the stimulation of renal gluconeogenesis produced by isoproterenol and parathyroid hormone is mediated by a release of cyclic AMP.