Testosterone in blood

Halogenated acyl derivatives of steroids have been applied in order to increase sensitivity of the analysis. It follows from a comparison of the ECD responses of haloacetates of steroids that the highest sensitivity can be obtained with the aid of monochloro-acetates [351]. Brownie et al. [352] applied them in the analysis of testosterone in blood. The method involves the extraction of blood plasma with diethyl ether, purification by TLC and derivatization. GC analysis is performed only after a preliminary separation on a thin layer. Preparation of the derivatives is carried out by treating a dried extract with... 

Measurement of Free and Weakly Bound Testosterone in Blood... 

In the equilibrium dialysis/ultrafiltration method for determining free testosterone in blood, a sample is first equilibrated with radioactive testosterone. Free steroid is then separated from bound steroid by filtration through an anisotropic, hydrophilic ultrafiitration membrane. The driving force for ultrafiltration is provided by centrifugation at 1000 to 2000 xg. Filtrate containing free steroid collects in the filtrate cup, whereas protein-bound steroid remains above the filter. Radioactivity in the filtrate is a measure of... 

Table 5. Level of testosterone in blood plasma of male M m, musculus or M. spicilegus after exposure to estrous of con- and heterospecific estrous females...

Steroids are generally converted to the HFB derivatives, which are more volatile and chromatographically mote favourable than the parent compounds. These O-HFB derivatives can be analysed with great sensitivity using GC with ECD. In some instances dehydration has been observed as a side reaction, so the milder the acylation conditions the better. Steroids are usually acylated in solvents. The dry steroid (up to Img) is treated with 1 4 HFBA in acetone (250 1) for one hour at room temperature, the mixture is blown dry with nitrogen and the derivatives are taken up in benzene for GC analysis [90]. In these conditions 17-hydroxyls and the enol form of 3-ketosteroids are acylated. The acetone concentration used is optimal. In a method for determination of testosterone in blood, the steroid extract is dried down and treated with HFBA (20 /il), n-hexane (1ml) and THF (40/il) at 50 °C for 30 minutes [91]. A similar recipe [92] involves a reaction time that is probably... 

The testosterone in blood plasma is very largely bound to serum albumin and also, in many species, to a plasma sex steroid-binding globulin that is produced by the liver and is quite different from in-... 

Estimation of Testosterone in Blood by Gas-Liquid Chromatograpliy Gas Chromatogr. Steroid Biol. Fluids,... 

Mass Fragmentographic Assay for Testosterone in Blood Using High Specific Activity Tritiated Testosterone as Internal Standard Clin. Chim. Acta 62(1) 163-168 (1975) CA 83 93314g... 

Mature males given weekly intraperitoneal injections of 20 or 50 mg Pb/kg BW as lead acetate for 6 weeks vs. 20 or 50 mg sodium acetate/kg BW as controls Dose-dependent increases in blood and sperm lead concentrations. Serum testosterone levels reduced in lead-exposed rats, possibly from generation of reactive oxygen species, and resulting in premature acrosome reaction and reduced sperm oocyte-penetrating capability 39... 

In a similar type of data collection, during 2000 to 2001 Wozniak (2002) examined the incidence of anabolic hormone residues in 5393 animals, consisting of cattle, pigs, horses, rabbits, chickens, geese, turkeys, ducks, and fish. Wozniak assayed for residues of diethylstibestrol, hexesterol, dienestrol, zeranol, trenbolone, and 19-noresterone. In addition, 632 cattle and swine were assayed for medroxyprogesterone and 1176 were assayed for natural 17-p-estradiol and testosterone. In only three heifers and two cows did serum testosterone exceed the MRL (EC 0.5 pg per liter) two bulls and four cows had an increased content of 17-(3-estradiol in their blood. A total of 11 animals of the 5393 examined (0.2%) had excessive quantities of hormone materials in their system. None of the other animals showed evidence of the presence of... 

Reports of studies with semen analyses have rarely included an evaluation of endocrine status (hormone levels in blood or urine) of exposed males (Adamopoulos et al., 1996 Larsen et al., 1999). Conversely, studies that have examined endocrine status typically do not have data on semen quality (McGregor Mason, 1990,1991 Egeland et al., 1994). Endocrine evaluation gives important information on reproductive organs. Estradiol, progesterone, testosterone, FSH, LH and prolactin are the hormones that are most informative. Inhibins and other more recently characterized factors may provide tools in the future. 

The vasoconstriction, which is caused by cadmium, may underlie the hypertension observed in experimental animals. Cadmium is also carcinogenic in experimental animals, causing tumors at the site of exposure. Also, Leydig cell tumors occur in the testis of animals after acute doses of cadmium sufficient to cause testicular necrosis. This seems to be an indirect effect due to the reduced level of testosterone in the blood, which follows testicular damage. This causes Leydig cell hyperplasia and tumors to occur. 

Key, T. Oakes, S. Davey, G. Moore, J. Edmond, L.M. MeLoone, U.J. Thurnham, D.I. 1996. Stability of vitamins A, C, and E, carotenoids, lipids, and testosterone in whole blood stored at 4 degrees C for 6 and 24 hours before separation of serum and plasma. Caneer Epidem. Biomar. 5 811-814. 

Furthermore Tait and co-workers [322] pointed out the marked difference in the urinary and blood production rates of testosterone obtained in women after injection of radioactive testosterone. He concluded that steroids produced from dehydroepiandrosterone contribute little to the blood production rate of androstenedione and testosterone in normal subjects [403]. According to Tait [324], all the blood production rate of androstenedione in the female and testosterone in the male is due to the same secreted steroid, while the blood production rate of testosterone in the female and androstenedione in the male is due about one-half to the same secreted steroid and one-half to converted precursor. The normal male secretes a ratio of testosterone to androstenedione of about 10 1 and the normal female secretes a ratio of androstenedione to testosterone of about 25 1. 

C2. Carstensen, H., Temer, N., Wide, L., and Thoren, L., Testosterone luteinizing hormone and growth hormone in blood following surgical trauma. Ada Chir. Scand. 138, 1-5 (1972). 

Maes M, Mommen K, Hendrickx D, Peelers D, D Hondt P, Ranjan R, et al. Components of biological variation, including seasonality, in blood levels of TSH, TT3, FT4, PRL, cortisol and testosterone in healthy volunteers. Clin Endocrinol 1997 46 587-98. 

Bremner WJ, Vitieho MV, Prinz PN. Loss of circadian rhythmicity in blood testosterone levels with aging in... 

Navarro MA, Alia P, Ruiz R, Valles A, Orozco P. Relationship between blood levels of sex hormone binding globulin, testosterone levels in blood and sahva and body morphology in premenopausal women. Medicina Clinica 1996 106 405-8. 

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