Plasma content

The most significant metabolic product of testosterone is DHT, since in many tissues, including prostate, external genitalia, and some areas of the skin, this is the active form of the hormone. The plasma content of DHT in the adult male is about one-tenth that of testosterone, and approximately 400 ig of DHT is produced daily as compared with about 5 mg of testosterone. About 50-100 ig of DHT are secreted by the testes. The rest is produced peripherally from testosterone in a reaction catalyzed by the NADPH-depen-dent 5oi-reductase (Figure 42-6). Testosterone can thus be considered a prohormone, since it is converted into a much more potent compound (dihydrotestosterone) and since most of this conversion occurs outside the testes. Some estradiol is formed from the peripheral aromatization of testosterone, particularly in males. 

From the above solution we can now easily determine the steady-state plasma content X after a sufficiently long time t ... 

If the CO2 plasma content is unknown, a safe average dose of sodium bicarbonate is 5 mEq (420 mg)/kg. 

There are a number of microdialysis studies in animals indicating that there is a consistent increase in extracellular glutamate concentration during experimental ischaemia (Benveniste et al. 1984 Globus et al. 1988). In man, there is also an increase in CSF and plasma content of glutamate and glycine in patients with progressive, but not with stable stroke (Castillo et al. 1997). 

Administered orally, oxibendazole is rapidly absorbed from the gastrointestinal tract. In sheep, the maximum plasma content is reached within 6 h. Much of the dose administered to cattle is eliminated in urine. 

Lumeng et al. (58) have reported the plasma content of Bg vitamers and its relationship to hepatic vitamin Bg metabolism. Orally ingested pyridoxine is rapidly metabolised in liver and its products are released into the circulation in the form of pyridoxal phosphate, pyridoxal, and pyridoxic acid. 

This volume provides a forum in which it is appropriate to discuss the bovine parathyroid gland and the effects of dopamine upon this tissue. When administered intravenously to cows, dopamine raises the plasma content of immunoreactive PTH (2). This stimulatory effect of dopamine is partially blocked by pimozide, a dopamine antagonist, but is unaffected by propranolol, a beta-adrenergic antagonist. An understanding of... 

Factor XII is a single polypeptide chain with a mass of 80 kDa, fully fucosylated at Thr 90 of the heavy chain in the N-terminal EGF domain [54]. The plasma content is 29. rg/ml. 

Transplacental passage of activity was evident a few minutes after maternal injection after 2.5 h, fetal plasma activity was in equilibrium with maternal plasma, showing 4.3% of the maternal plasma concentration, totally as free " Tc-pertechnetate. However, the total plasma content in the fetus never exceeded 0.15% of the maternal administered activity. Urine immediately obtained after birth showed high concentrations of free Tc-pertechnetate. Passage of " Tc-HSA across the placenta is minimal (Herbert et al. 1969). 

Reasons for the discrepancies in fatigue resistance may stem from factors related to the nature of the experiment, including the in vitro or in vivo aspect of muscle perfusion, flow rate and blood/plasma contents (Schaafsma et al, 2002 Vedsted et aL, 2003). The hypothyroidism-induced reduction in cardiac output and blood perfusion during exercise (Bausch and McAllister, 2003 McAllister et al, 1991, 1995) may limit the supply of oxygen and metabolic substrates, and thus result in reduced fatigue resistance when measured in vivo. 

Recently, Houk s laboratory [18,19] described a direct injection nebulizer for use in ICP-MS consisting of a stainless steel tube with an inner diameter of 250 p.m held in a ceramic support tube that is inserted directly into the quartz injector tube of the ICP torch. A positive displacement gas pump is used to achieve a sample flow rate of 120 p,L/min. The low flow rates decrease sample consumption and the essentially 100% transfer efficiency improves detection limits by an order of magnitude. However, solvent loading presents a difficulty and the plasma content of solvent-derived polyatomics such as metal oxides was increased up to threefold [18]. 

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