Lead metabolism in lactation

Summary A 2-fold increase in lead absorption was observed in lactating animals which received 2 mg Pb/1 in drinking water. About one-half of the absorbed lead was transferred to the litters.Acknowledgments. This work was partially supported by a research grant from the US Environmental Protection Agency and the US Public Health Service.     

Methionine metabolism in apple tissue

Summary A metabolic intermediate isolated from apple tissue fed either methionine or 5-methylthioadenosine has been tentatively identified as a methionine-pyridoxal Schiff base. The formation of this compound is discussed in relation to ethylene biosynthesis.Acknowledgments. This investigation was supported by Research Grant AO-150 from the National Research Council of Canada.     

Antipyrine metabolism in cancer patients

Summary The metabolism of antipyrine was studied in cancer patients. Antipyrine elimination might be decreased in cancer patients. Increase in antipyrine half-life is not primarily due to the presence of a tumor but rather to the nutritional status and liver function of an individual.     

Phospholipid metabolism in pancreatic islets

Conclusions The secretion of insulin can be elicited by a wide spectrum of stimuli including nutrients, hormones and neurotransmitters as well as a large number of pharmacological agents such as tumor-promoters and sulphonylureas. The diversity of these secretagogues suggests that islets may be activated through a number of distinct biochemical mechanisms. The work discussed in this review suggests that certain of the above-mentioned secretagogues, especially nutrient and neurotransmitter stimuli, may induce insulin secretion by a mechanism involving enhanced metabolism of inositol-containing lipids. The way in which this process is coupled to secretion is not known, although several possibilities exist. The hydrolysis of phosphoinositides and release of inositol phosphates may result, respectively in altered calcium permeability of the plasma membrane and mobilization of calcium from intracellular sources. The accompanying production of diacylglycerol might also influence membrane permeability and fluidity and also lead to activation of protein kinase C. Diacylglycerol can be phosphorylated to form phosphatidic acid which may play a role as an endogenous ionophore. Finally, inositol lipid breakdown could lead, through diacylglycerol and/or phosphatidic intermediates, to the liberation of arachidonic acid and subsequent conversion to active metabolites of the cyclo-oxygenase and lipoxygenase pathways. Thus, enhanced phospholipid metabolism in islets could, theoretically, result in the generation of a range of intracellular signals which mediate or modulate insulin secretion during stimulation by certain types of secretagogues. Continued investigation is clearly neccessary in order to elucidate the mechanisms by which such secretagogues provoke increased phospholipid metabolism and to understand the role(s) of this process in the regulation of islet function.     

Lead metabolism in lactation.

A 2-fold increase in lead absorption was observed in lactating animals which received 2 mg Pb/l in drinking water. About one-half of the absorbed lead was transferred to the litters.     

Trypsin inhibitor in plant metabolism

Résumé L'activité inhibitrice de la trypsine contenue dans les différentes parties deFaba vulgaris Mnch etDolichos lablab L., pendant germination, et des plantules et de leurs parties en voie de croissance a été déterminée à trois différents stades, à savoir aux états: 1° de tendre, 2° de demi-maturité et 3° de maturité. On l'a constatée aux trois stades. Sauf dans les graines, l'activité inhibitrice diminue avec la maturation. Dans les graines c'est l'inverse, l'activité inhibitrice de la trypsine augmente avec la maturité. On suggère le rôle possible de ce principe comme régulateur dans le processus de formation et de rupture de la protéine.     

Defective phosphoinositide metabolism in primary hypertension

An increase in free cytosolic calcium content has been reported in essential hypertension. Since within the membrane, the phosphoinositides participate in the control of cell calcium homeostasis, we investigated whether impaired phosphoinositide metabolism could account for the calcium handling abnormality observed in hypertensives. In erythrocyte membranes of hypertensives the activity of kinases involved in polyphosphoinositide formation appears to be impaired and could be related to the alteration in calcium handling binding capacity and ATP-dependent calcium transport. In platelets of hypertensives, the hyperactivity of phospholipase C (observed even in the absence of calcium in the external medium) is likely to be responsible for the hypersensitivity of cells to various agonists. These observations are consistent with the hypothesis that in cells from hypertensives, a membrane defect linked to phosphoinositide metabolism is involved in the overall calcium handling defect.     

Ethanol metabolism in Drosophila melanogaster.

A quantitative study of the transformation of ethanol into acetaldehyde shows that, in Drosophila melanogaster, the mitochondrial ethanol oxidizing system is not very active but that the part played by catalase appears more important than expected. For a strain without alcoholdehydrogenase, ethanol is highly toxic. The presence of acetaldehyde in the culture medium is toxic for all the strains studied. But, since even a strain without any aldehydeoxidase lives normally, the metabolic production of acetaldehyde does not seem dangerous.     

Oximinoacids in the inorganic nitrogen metabolism

Zusammenfassung Es wird gezeigt, dass in Zellen vonCryptococcus albidus und in Kulturlösung vonEndomycopsis lipolytica die Oxime bis zur Mitte der exponentiellen Zuwachsphase in steigenden Konzentrationen vorkommen, während sie in Ammonium-kultivierten Zellen fehlen.     

Pyruvate metabolism in epileptic tuberculous patients

Résumé Les auteurs ont étudié la variation de la concentration de l'acide pyruvique dans le sang de 3 tuberculeux épileptiques. Ils ont vérifié l'existence d'un cycle dont le maximum coïncide avec la crise épileptique et dont le minimum la précède et semble la causer. L'effet nuisible de l'isoniazide pour les épileptiques serait dû à la consommation accélerée de l'acide pyruvique, utilisé pour la formation de l'hydrazone respective.     

Testosterone induced alterations in histamine metabolism in mice

Zusammenfassung Eine neuer Befund von hormonaler Beeinflussung des Histaminmetabolismus wird beschrieben und ein bisher nicht erkannter Metabolit wird chromatographisch nachgewiessen. Under dem Einfluss von Testosteron wird der Metabolit in grosser Menge in Urin der Maus ausgeschieden, während zugleich freies Histamin fast verschwindet, was dafür spricht, dass es sich um einen Histaminmetaboliten handelt, dessen chemische Struktur noch nicht festgestellt ist und von verschiedenen bekannten Histaminmetaboliten abgegrenzt werden kannte.

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This study was supported by grants from the Swedish Medical Research Council No. B70-14x-2212-04 and from the Swedish Society for Cancer Research No. 268-K70-01 X.