Biomedical subjects

J V Olhaberry

Publications and source records attributed to J V Olhaberry.

6 recordsLinked to original sources

PubMed1983

Zinc, angiotensin I-converting enzyme and hypertension.

Angiotensin-converting enzyme, or kininase II, is a zinc metallo-enzyme; the cation forms part of its active site. The enzyme transforms angiotensin I into angiotensin II and hydrolyses bradykinin into inactive peptides. Antihypertensive diuretics may decrease the activity of the angiotensin-converting enzyme by increasing urinary zinc excretion. Captopril inhibits the angiotensin-converting enzyme, but also affects electrolyte excretion and should be reassessed as a possible first-choice antihypertensive agent in the treatment of essential hypertension.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1983

Urinary zinc excretion, diuretics, zinc deficiency and some side-effects of diuretics.

Diuretics which principally act in the first portion of the distal convoluted tubule, such as the thiazides and chlorthalidone, significantly increase the urinary excretion of zinc. The potassium-retaining diuretic amiloride reduced urinary zinc excretion significantly. The hyperzincuria provoked by common distal tubular diuretics can cause zinc deficiency, especially when other aetiological factors such as alcoholism, renal insufficiency and pregnancy are also present. Zinc deficiency may be expressed clinically by hypogeusia, hyposmia, sexual impotence or delayed healing; the latter might be an important factor in cases of myocardial infarction.

Adult↗

PubMed1983

Biochemistry of zinc.

Zinc forms part of the active site and/or stabilizes the conformation of several enzymes. The protein metallothionein constitutes a zinc deposit from which the metal is transferred to enzymes. Zinc participates in the synthesis of nucleic acids and hence in the synthesis of proteins, principally through multi-enzyme pir 1-3 and DNA-dependent RNA polymerase, which are metallo-enzymes of zinc. Zinc is therefore necessary for normal growth, development, healing and ossification.

Alcohol Oxidoreductases↗

PubMed1983

Zinc metabolism under physiological conditions.

Zinc is the sixth commonest cation in the human body. The daily dietary requirement for adults is 15 mg, and foods of animal origin are the richest dietary source. Zinc absorption (10-25% of the ingested amount) occurs in the small intestine. Plasma zinc is transported mainly by protein and also by amino acids. Zinc is widely distributed throughout the body, and is mainly excreted in faeces but also in urine and sweat.

Adult↗

PubMed1983

Biochemical functions of magnesium.

Magnesium is required by many enzymes as a co-factor and may couple primarily with the enzyme or the substrate in different reactions. Free cytosolic magnesium affects cell energy, the action of various hormones on target cells, protein synthesis and cellular electrolyte content. Magnesium enters the cell by a process of facilitated diffusion requiring a transporter, and leaves it by an active process utilizing adenosine triphosphate.

Cells↗

PubMed1983

Magnesium--distribution and basic metabolism.

Magnesium is extensively distributed in soil, water and plants. It is essential for enzymatic reactions requiring adenosine triphosphate, and the recommended dietary allowance in man is 5-10 mg/kg/d. About 50% of magnesium in man is stored in bone, where it is regulated by parathyroid hormone and 1,25(OH)2-D3. Most of the remaining magnesium pool is intracellular, plasma magnesium accounting for less than 0,5% of the total.

Food Analysis↗