Individual metabolism

When galactose is fed to a normal animal or individual it is converted to glycogen. The conversion takes place mostly in the liver, to a lesser degree in many other tissues. This has been known since 1911 (Mil) but it is only recently that the individual metabolic steps have been worked out. 

Individual metabolism cages are recommended for collecting urine and feces in oral dosing studies. Excreta should be collected for at least 5 elimination half-lives of the test substance. When urine concentrations will be used to determine elimination rates, sampling times should be less than one elimination half-life (taken directly from the bladder in IV studies) otherwise, samples should be taken at equal time intervals. 

The application of sum or group-specific parameters to quantify low amounts of surfactants in environmental samples and to pursue their fate therein does not require the employment of advanced analytical techniques however, it also does not provide detailed information on the individual metabolisms. In addition to this shortcoming, the sum parameter analysis on a spectrophotometric and titrimetric basis,... 

Subject variability High intraindividual variability in QTc values (circadian and seasonal variation law of regression to the mean) High interindividual variability in QTc values (males versus females) Unknown prevalence in the general population of subjects carrying silent mutations in the ion channels responsible for cardiac repolarization (these subjects have normal QTc value but reduced repolarization reserve) Variability in the individual metabolic capacity for a given drug... 

When the steady state is disturbed by some change in external circumstances or energy supply, the temporarily altered fluxes through individual metabolic pathways trigger regulatory mechanisms intrinsic to each pathway. The net effect of all these adjustments is to return the organism to a new steady state—to achieve homeostasis. 

To appreciate fully the significance of individual metabolic pathways and their regulation, we must view these pathways in the context of the whole organism. An essential characteristic of multicellular organisms is cell differentiation and division of labor. The specialized... 

As stated earlier, the annual cycles of species and populations divide into periods. The overall description would be the syndrome of the population, while individual metabolic characteristics would be symptoms , borrowing terms from the medical profession. Each period manifests a specific set of metabolic features which support the normal course of vital processes in the population, and the population would enter the next period of the cycle only if the preceding step had been completed. If it had not, the situation would lead to that mass mortality which is so common in nature. The change in metabolism is triggered with the help of the endocrine system, as will be described in the next section. 

The long-term metabolism of metribuzin is very complex. Given the extended length of these experiments, identifying the individual metabolic pathways has been very challenging. Also, some degradation of metribuzin occurs in the treated soil before plant uptake occurs (Schumacher, 1974 Prestel et al, 1976). 

Be able to give the effects of insulin, glucagon, epinephrine, and the glucocorticoids on individual metabolic processes, and explain how these pathways change and interact if such hormone levels should change. 

Fasted Cebus monkeys (Cebus albifrons) of either sex weighing 3.0 to 5.0 kg are used. On the morning of the experiment, the animals receive 20 ml/kg drinking water by gavage, followed by oral administration of the test compound. Allopurinol and probenecid are used as control compounds. Control animals receive water only. The animals are placed in individual metabolism cages and the spontaneously voided urine is collected after 2, 6, and 24 h. After 2 and 6 h, an additional 4 ml/kg water is given by gavage. From a cubital vein blood is withdrawn prior to the experiment and 2, 6 and 24 h after application. 

The animals are housed in individual metabolic cages. For bile collection, they are attached to long swivelled PE-cannulas (0.75 x 1.45 mm). A stainless steel coil is used to protect the rats from gnawing on the tubing. For continuous collection of bile, the cannula can be connected to a fraction collector. 

A genetic characteristic in humans that determines how rapidly a particular individual metabolizes certain drugs, acetylcholine... 

Do some individuals metabolize the new drug differently such that those individuals could have serious and life-threatening... 

Some patients do achieve response or remission at subtherapeutic doses, for reasons of drug kinetics and individual metabolism, the self-limiting nature of depression or by a placebo effect (reinforced by the experience of side effects suggesting that the drug must be having some action). 

---