Zn-excess intake augmented blood pressure (BP) and reduced renal blood flow (RBF) and inulin clearance. The decline in inulin clearance may be due to a fall in RBF. Treatment with the nitric oxide (NO) synthase inhibitor, L-NAME, further increased BP and markedly decreased RBF in the Zn-excess condition. Inversely, administration of the exogenous superoxide radical scavenger, tempol, significantly decreased BP and substantially increased RBF in the Zn-excess setting. As a result, tempol dramatically restored BP and RBF levels seen in the Zn-excess setting to levels comparable to those observed in the control setting. These observations suggest that both an increment in BP and a decrement in RBF seen in the Zn-excess condition come from a decrement in the action of the vasodilator, NO, via the formation of peroxynitrite based upon the non-enzymatic reaction of NO with increased superoxide radical. Indeed, the activity of the endogenous superoxide radical scavenger, Cu/Zn-superoxide dismutase (SOD), was significantly decreased in the vessel wall of the Zn-excess vs. the control setting. The reduction in the activity of Cu/Zn-SOD in the Zn-excess setting was the result of Cu deficiency secondary to Zn-excess ingestion. With respect to BP, RBF, inulin clearance, L-NAME and tempol treatment and the activity of Cu/Zn-SOD, similar results were observed in the Zn-deficient setting. Thus, inadequate ingestion of Zn leads to the deterioration of BP and renal function through the oxidative stress caused by superoxide radical.
Iron (Fe) and zinc (Zn) are apt to be depleted in humans at the same time because of common food sources and common absorption inhibitors. In fact, there were several reports on the occurrence of simultaneous deficiency of Fe and Zn in some populations. Although many researchers investigated single deficiency of Fe or Zn, their interactions on biochemical and biological parameters are not clearly defined. We tried to determine the effect of dietary Fe and/or Zn deficiencies on rectal temperature, blood pressure, body water distribution, plasma erythropoietin level, blood biochemical parameters (lipids, protein and enzyme activity) and plasma mineral concentrations using experimental rats as a model for human zinc metabolism. Effects of combined deficiency of Fe and Zn were significantly different from those of single deficiency of Fe or Zn especially in body temperature. Body temperature was decreased by single deficiency of Fe or Zn, but combined deficiency of Fe and Zn did not change the temperature. Blood pressure is most decreased by combined deficiency of Fe and Zn, and plasma aldosterone concentration is also decreased by it. Fe and Zn deficiencies affect plasma Fe and Zn concentrations each other. Hence, future advancement of investigations on trace element interaction especially Fe and Zn is awaited.
Zinc is an essential microelement for all organisms, however the optimal concentration of zinc in the cytosol is very low, and excess amounts of zinc are toxic for organisms. Therefore intracellular zinc concentration is adjusted strictly by zinc-transporters. The cation diffusion facilitator (CDF) family plays an important role in order to decrease cytosolic zinc concentration. To understand the mechanisms of zinc homeostasis in plants, we studied the Arabidopsis CDF family and found structures that allow the regulation of ion transport activity. This article introduces the structure-function relationship of the Arabidopsis CDF proteins, while comparing them to CDF-type proteins from other organisms.
The Periodic Table of the Elements (PTE), which was discovered by a Russian chemist Dimitri Mendeleev in 1869, is the most important and the most fundamental table in not only science but our daily life. In modern PTE, 114 sorts of the elements, given the characteristic name and the symbol of each element, are arranged, among them 90 sorts of the elements are found to occur in nature. We know that approximately 21 sorts of the elements including trace elements are essential in our daily life and health or in treatment of some disorders. The names of these essential elements have been well known, however, understanding of the significance of occurrence in living systems of these elements are limited in many people. In this article, a possible significance of the essential elements including essential trace elements is discussed on the perspective for the histories of appearance of the earth, evolution of life, and discovery of elements in human and animal bodies and fluids, as well as the deficiency of some metal elements in our daily life. On the basis of the short discussion, “elements are our best friends” is proposed in our life and health.
Carnosine (β-alanyl histidine) is a small dipeptide highly present in the skeletal muscles and in the nervous system. Carnosine and its analogue anserine (1-methylated carnosine) perform various beneficial characteristics such as the maintenance of the pH balance and exert anti-glycation, anti-oxidant, anti-crosslinking effects. Increasing evidence suggests the implication of carnosine in the prevention of neurodegenerative diseases. We have revealed that carnosine attenuated zinc-induced neurodegeneration and become a possible treatment for vascular dementia. Thus, we have developed a system for the quantitative analysis of carnosine and its analogues using high performance liquid chromatography, and analyzed the content of carnosine and anserine in various foods such as meats and fishes. Our results suggest that concentrations of carnosine and anserine were different among spices and varied according to regions. Our results may aid for the development of carnosine supplementation from foods.