Water metabolic

Fatty Acid Oxidation Is an Important Source of Metabolic Water for Some Animals... 

Calculate the volume of metabolic water available to a camel through fatty acid oxidation if it carries 30 lb of triacylglycerol in its hump. 

Figure 10.13 Hyphae of Fusarium alkanophllum from light hydrocarbons producing important amounts of metabolic water from the substrate. In cultures for more than 90 days, drops of water associated to the soluble degraded products were observed. Scale = 10.5 xm (Light Microscope image). (Reproduced from Marcanoa, 2002, by permission of Elsevier)...

The metabolic water formed by oxidation of foods and stored fats is actually enough to allow some animals in very dry habitats (gerbils, kangaroo rats, camels) to survive for extended periods without drinking water. 

Somatotropin (STH) (Growth hormone, GH somatotrophic hormone hypophyseal growth hormone) Structure Known and synthesized coiled, unbranched Promotes general growth of organism Promotes skeletal growth, protein anabolism, fat metabolism, carbohydrate metabolism, water, and salt meiabolism Relates with all vitamins in connection with growth actions... 

Desert rodents lead the most water-independent life of all vertebrates. Kangaroo rats can so reduce their evaporation that they are able to maintain water balance on only metabolic water. Other species survive on only meiabolic water plus free water in air-dry seeds. Respiratory water loss is reduced by cool nasal mucosal surfaces, which condense water from warm air coming from the lungs, before it can be expired. Skin impermeability involves a physical vapor barrier in the epidermis, pins unknown physiological factors. 

These reduced coenzymes can be oxidized in the electron-transport system to produce metabolic water and ATP. 

Defects in salt metabolism, water balance leading to arterial hypertension... 

Krutch, J. W. The Voice of the Desert. New York Morrow, 1975. [Chapter 7, The Mouse That Never Drinks, is a description, primarily from a naturalist s point of view, of the kangaroo rat, but it does make the point that metabolic water is this animal s only source of water.]... 

These animals do not make urea rather, they convert all their waste nitrogen to uric acid (Figure 23.17), the concentrated white solid so familiar in bird droppings. Some desert mammals, such as the kangaroo rat, which never drinks water but rather lives off metabolic water, also convert some of their waste nitrogen to uric acid to conserve the water used in urine. 

The humps of camels contain lipids that can be degraded as a source of metabolic water, rather than water as such. 

When the body breaks down proteins to supply material for gluconeogenesis, the increased urea output results in greater urine production, which uses water stored in the body. Fat metabolism also produces much metabolic water. 

Water is the most abundant and surely the most frequently overlooked component in foods. It is estimated that over 35% of our total water intake comes from the moisture in the foods we consume [2]. The other contributors to our water intake are beverages and metabolic water, which is produced through chemical reactions in the body. 

The camel does not store water in its hump but fat, which is a source of metabolic water. 

If spoilage microbes produce metabolic water that enhances further spoilage, suggest ways to break or avoid this cycle. 

Water Intake Metabolic Water Urine All Other... 

Comment An average adult ingests 2 L of water daily and eliminates 2.4 L. The extra 0.4 L is produced in the metabolism of foodstuffs, such as oxidation of glucose. The desert rat (kangaroo rat), on the other hand, apparently never drinks water. It survives on its metabolic water. 

The biosynthesis and degradation of marine wax esters and hydrocarbons has been reviewed by Sargent et al. (1976). So far as functions are concerned the wax esters may serve as a source of metabolic energy or of metabolic water, for buoyancy, as biosonar (e.g. in the head regions of whales, porpoises) or for thermal insulation. Further details can be found in Sargent et al, (1976). 

A damaged kidney cannot eliminate all the water that is ingested and produced through metabolism. Water retention has a triple effect—it turns off ADH secretion, reduces the osmolarity of the plasma and the extracellular fluid, and increases the plasma volume. The increase in plasma volume triggers the volume receptors and stimulates diuresis. If water diuresis does not compensate for the water intake and production, the hypotonicity is corrected by sodium retention, and the vicious circle is closed. 

Figure 48. Relationship between water flux determined by HTO dilution and the total water input, i.e., the sum of measured water intake plus calculated metabolic water production (trials A-K). From Cameron et al. (1976).

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