Inhibition of hepatic gluconeogenesis by phenethylhydrazine (phenelzine)

Ultra-fast and visual detection of hydrazine hydrate based on a simple coumarin derivative

A cleverish fluorescence probe based on coumarin was developed, exhibiting remarkable color change, strong fluorescence enhancement and fast response when it interacts with hydrazine in water solution. The limit of detection (LOD) is 5.59 × 10^-6 M for ultraviolet analysis and 8.18 × 10^-8 M for fluorescence analysis, respectively. Taking advantage of good sensitivity and short response time, the probe was applied to test hydrazine in water and to observe hydrazine in living cells.

Past, Present and Future Anti-Obesity Effects of Flavin-Containing and/or Copper-Containing Amine Oxidase Inhibitors

Background: Two classes of amine oxidases are found in mammals: those with a flavin adenine dinucleotide as a cofactor, such as monoamine oxidases (MAO) and lysine-specific demethylases (LSD), and those with copper as a cofactor, including copper-containing amine oxidases (AOC) and lysyl oxidases (LOX). All are expressed in adipose tissue, including a semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 (SSAO/VAP-1) strongly present on the adipocyte surface. Methods: Previously, irreversible MAO inhibitors have been reported to limit food intake and/or fat extension in rodents; however, their use for the treatment of depressed patients has not revealed a clear anti-obesity action. Semicarbazide and other molecules inhibiting SSAO/VAP-1 also reduce adiposity in obese rodents. Results: Recently, a LOX inhibitor and a subtype-selective MAO inhibitor have been shown to limit fattening in high-fat diet-fed rats. Phenelzine, which inhibits MAO and AOC, limits adipogenesis in cultured preadipocytes and impairs lipogenesis in mature adipocytes. When tested in rats or mice, phenelzine reduces food intake and/or fat accumulation without cardiac adverse effects. Novel amine oxidase inhibitors have been recently characterized in a quest for promising anti-inflammatory or anti-cancer approaches; however, their capacity to mitigate obesity has not been studied so far. Conclusions: The present review of the diverse effects of amine oxidase inhibitors impairing adipocyte differentiation or limiting excessive fat accumulation indicates that further studies are needed to reveal their potential anti-obesity properties.

Hydrazine selective dual signaling chemodosimetric probe in physiological conditions and its application in live cells

A rhodamine-cyanobenzene conjugate, (E)-4-((2-(3',6'-bis(diethylamino)-3-oxospiro[isoindoline-1,9'-xanthene]-2-yl)ethylimino)methyl)benzonitrile (1), which structure has been elucidated by single crystal X-ray diffraction, was synthesized for selective fluorescent "turn-on" and colorimetric recognition of hydrazine at physiological pH 7.4. It was established that 1 detects hydrazine up to 58 nM. The probe is useful for the detection of intracellular hydrazine in the human breast cancer cells MCF-7 using a fluorescence microscope. Spirolactam ring opening of 1, followed by its hydrolysis, was established as a probable mechanism for the selective sensing of hydrazine.

Advances pertaining to the pharmacology and interactions of irreversible nonselective monoamine oxidase inhibitors

Recent advances clarifying the pharmacology and interactions of irreversible nonselective monoamine oxidase inhibitors that have not been considered in depth lately are discussed. These new data elucidate aspects of enzyme inhibition and pharmacokinetic interactions involving amine oxidases, cytochrome P450 enzymes, aminotransferases (transaminases), and decarboxylases (carboxy-lyases) and the effects of tyramine. Phenelzine and tranylcypromine remain widely available, and many publications have data relevant to this review. Their effect on CYP 450 enzymes is less than many newer drugs. Tranylcypromine only inhibits CYP 450 2A6 (selectively and potently). Phenelzine has no reported interactions, but, like isoniazid, weakly and irreversibly inhibits CYP 450 2C19 and 3A4 in vitro. It might possibly be implicated in interactions (as isoniazid is). Phenelzine has some clinically relevant inhibitory effects on amine oxidases, aminotransferases, and decarboxylases, and it lowers pyridoxal phosphate levels. It commonly causes pyridoxal deficiency, weight gain, sedation, and sexual dysfunction, but only rarely causes hepatic damage and failure, or neurotoxicity. The adverse effects and difficulties with monoamine oxidase inhibitors are less than previously believed or estimated, including a lower risk of hypertension, because the tyramine content in foods is now lower. Potent norepinephrine reuptake inhibitors have a strong protective effect against tyramine-induced hypertension. The newly discovered trace amine-associated receptors probably mediate the pressor response. The therapeutic potential of tranylcypromine and L-dopa in depression and Parkinson disease is worthy of reassessment. Monoamine oxidase inhibitors are not used to an extent proportionate with their benefits; medical texts and doctors' knowledge require a major update to reflect the evidence of recent advances.

Combination of ‘omics’ data to investigate the mechanism(s) of hydrazine-induced hepatotoxicity in Rats and to identify potential biomarkers

To gain novel insight into the molecular mechanisms underlying hydrazine-induced hepatotoxicity, mRNAs, proteins and endogenous metabolites were identified that were altered in rats treated with hydrazine compared with untreated controls. These changes were resolved in a combined genomics, proteomics and metabonomics study. Sprague-Dawley rats were assigned to three treatment groups with 10 animals per group and given a single oral dose of vehicle, 30 or 90 mg kg(-1) hydrazine, respectively. RNA was extracted from rat liver 48 h post-dosing and transcribed into cDNA. The abundance of mRNA was investigated on cDNA microarrays containing 699 rat-specific genes involved in toxic responses. In addition, proteins from rat liver samples (48 and 120/168 h post-dosing) were resolved by two-dimensional differential gel electrophoresis and proteins with changed expression levels after hydrazine treatment were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry peptide mass fingerprinting. To elucidate how regulation was reflected in biochemical pathways, endogenous metabolites were measured in serum samples collected 48 h post-dosing by 600-MHz 1H-NMR. In summary, a single dose of hydrazine caused gene, protein and metabolite changes, which can be related to glucose metabolism, lipid metabolism and oxidative stress. These findings support known effects of hydrazine toxicity and provide potential new biomarkers of hydrazine-induced toxicity.

In vivo and in vitro effects of a new hypoglycemic agent, 2-(3-methylcinnamylhydrazono)-propionate (BM 42.304) on glucose metabolism in guinea pigs

A new compound, 2-(3- methylcinnamylhydrazono )-propionate (BM 42.304), showed a dose dependent hypoglycemic effect in starved guinea pigs after both oral and intraperitoneal administration. In contrast to biguanides (phenformin and metformin) the new compound produced only a moderate increase in blood lactate concentration and did not alter the content of adenine nucleotides in the freeze-clamped liver in vivo. Gluconeogenesis from a variety of precursors in the perfused guinea-pig liver was also inhibited by BM 42.304. These properties suggest that the compound deserves further investigation in connection with its potential usefulness for the treatment of diabetes.

Studies on the mechanism of action of the hypoglycemic agent, 2-(3-methylcinnamylhydrazono)-propionate (BM 42.304)

A new hypoglycemic agent, 2-(3-methylcinnamylhydrazono)-propionate MCHP (BM 42.304) was shown to be an inhibitor of the transfer of long-chain fatty acids across the mitochondrial inner membrane. The following data support this conclusion: the drug, at already 5 microM, inhibited ketogenesis from oleate but not from octanoate in the perfused guinea-pig liver; likewise, ketogenesis from L-(-)-palmitoylcarnitine and palmitoyl-CoA + L-(-)-carnitine, but not from octanoate, was depressed in isolated guinea-pig liver mitochondria. Oxigraphic measurements of the oxygen uptake by isolated mitochondria showed that the drug impaired oxygen uptake with the long-chain fatty acid derivatives but not with octanoate. Finally, in vivo effects of the drug such as hypoketonemia and an increased concentration of free fatty acids in blood are in agreement with the above formulated mechanism of action. A comment is given on the relationships between fatty acid oxidation and gluconeogenesis in the guinea-pig liver.

The reaction of amines with carbonyls: its significance in the nonenzymatic metabolism of xenobiotics

The studies cited above indicated that many carbonyl amine reactions can alter both in vitro and in vivo rates of xenobiotic metabolism. The carbonyl amine reaction may be enzymatic or nonenzymatic and in most instances is readily reversible with few examples of the isolation and identification of the Schiff bases (azomethine). Endogenous primary amine and amines generated by metabolic N-dealkylation can react with biogenic ketones and aldehydes and under selected physiological conditions give further condensation products. The new products in most instances alter the biological activity and/or toxicity. It is apparent that these findings can be extended to carbonyl hydrazine reactions. The rates of reaction for simple alkyl and aryl hydrazine are more rapid and the products of these reactions and more stable, with the condensation products of alpha-keto acids being isolated and characterized the most frequently. The further reaction of hydrazones to yield condensation products is also observed with selected hydrazines such as hydralazine. It is now clear that the inherent toxicity of many exogenous ketones and aldehydes exists. Many of these toxicities are due to the reactions which occur with the amino groups of amino acids and proteins. The condensation reactions in most instances are readily reversed and are only dependent on the physiological concentration of aldehydes of ketones. However, there are a number of ketones and aldehydes, some of which are metabolically produced that are capable of forming azomethine intermediates which are not readily reversed under physiological conditions. There are an increasing number of examples of further nonenzymatic condensations which result in stable products which can alter xenobiotic metabolism.