Part of the interindividual variation in serum testosterone levels in healthy men reflects differences in androgen sensitivity and feedback set point: contribution of the androgen receptor polyglutamine tract polymorphism.

CONTEXT: There is a large interindividual variation in serum (free) testosterone (FT) levels in men, underlain in part by genetic components. OBJECTIVE: The objective of the study was to explore the hypothesis that this variability results in part from differences in androgen sensitivity and feedback loop set point and assess the role of the androgen receptor (AR) polyglutamine tract polymorphism encoded by a CAG repeat of variable length in exon 1 of the AR gene. DESIGN/SETTING/PARTICIPANTS: We performed a cross-sectional analysis in two independent populations of healthy men, consisting of 2322 men aged 35-59 yr (Belstress study) and 358 men aged 25-45 yr (Siblos study), respectively. MAIN OUTCOME MEASURES: Serum hormonal levels and the AR gene CAG repeat length were determined. RESULTS: In the Belstress population, serum testosterone and calculated FT showed a positive linear association with LH (P < 0.001). In the 200 men with lowest FT, CAG repeat number was lower than in the 200 men with highest FT (P = 0.004). As studied in a larger subset of the population consisting of 857 men covering the whole FT range, FT increased progressively with CAG repeat length (P = 0.003). These findings of a positive relation of FT with both LH and CAG repeat length were confirmed in the Siblos study population (both P < or = 0.001). Difference in FT between extreme quartiles of CAG repeat was 10 and 14% in the Belstress and Siblos study, respectively. In both study populations, CAG repeat length was also positively associated with serum total testosterone (P < or = 0.004). CONCLUSIONS: The data support the view that between-subject variability in serum FT in healthy men is underlain in part by differences in androgen sensitivity and feedback set point, with a contributory role of AR polymorphism. These findings have potential implications for the interpretation of epidemiological studies, diagnosis of hypogonadism, and pharmacogenetics of androgen treatment in men.

Is the effect of testosterone on body composition modulated by the androgen receptor gene CAG repeat polymorphism in elderly men?

OBJECTIVE: The androgen receptor (AR) gene contains a CAG repeat polymorphism coding for a polyglutamine chain, the length of which is inversely correlated with AR transcriptional activity. We explored whether this polymorphism modulates the activities of testosterone (T) related to body composition in elderly men. DESIGN: We performed cross-sectional analyses using data from a 4-year follow-up study in community-dwelling men aged 75-89 years (n=159). METHODS: Body composition was assessed by dual-energy X-ray absorptiometry and its relation with T and the AR gene CAG repeat length was assessed by multiple linear regression analyses, adjusting for confounding and exploring effect modification. RESULTS: AR gene CAG repeat length was not directly related to body composition, either with or without adjustment for confounding variables like age, weight, total T or sex hormone binding globulin (SHBG) levels. However, exploration of effect modification showed that CAG repeat length modulated the relation between T and body composition (standardized regression coefficients of interaction term: beta=0.12, P<0.01 and beta=-0.09, P<0.05 for fat-free mass and fat mass respectively). These results were confirmed using similar models and data of mean T, SHBG and weight of the 2 years' preceding body composition assessment instead of data of the same year (beta=0.09, P<0.05 and beta=-0.09, P<0.05 respectively). CONCLUSION: These findings suggest that the AR gene CAG polymorphism contributes, albeit modestly, to the between-subject variation of T action on body composition in community-dwelling elderly men.

Preliminary evaluation of a lateral flow immunoassay device for screening urine samples for the presence of sulphamethazine.

A lateral flow immunoassay (LFIA) device was developed and applied to testing urine samples for residues of the antimicrobial sulphamethazine (SMZ). This report describes the preparation of a rat monoclonal antibody to SMZ and its characterisation in an ELISA format. Apart from SMZ, the antibody showed high (> or =50%) cross-reactivity to N4-acetyl-sulphamethazine (55%), sulphamerazine (59%) and sulphisoxazole (50%) and lower cross-reactivity of 18% to sulphachlorpyridazine and sulphadiazine. The LFIA device consisted of a nitrocellulose membrane spotted with SMZ-ovalbumin and goat anti-mouse antibody as capture line and control line, respectively. Mouse anti-rat IgG F(ab')2 fragment specific antibody, adsorbed to colloidal carbon, was used as the detection ligand in the LFIA. The LFIA device had a cut-off value of 6.3 ng/ml in diluted (1/10) urine. Urine samples from SMZ-treated pigs, and bovine and porcine urine samples fortified with SMZ were used for a blind, four-laboratory evaluation of the performance of the LFIA device. Concentrations of SMZ in the test samples (n=29), as determined by LC-MS/MS, ranged from 0 (<3) to 1174 ng/ml. The evaluation of the LFIA device showed an overall sensitivity of 100%, a specificity of 71%, and positive and negative prediction values of 73% and 100%, respectively. The LFIA device has been fabricated as a test kit for determining SMZ residues in animals produced for slaughter.

Influence of the hapten conjugation site on the characteristics of antibodies generated against metabolites of clostebol acetate.

4-chloro-androst-4-ene-3,17-dione (CLAD) and 4-chlorotestosterone (clostebol, beta-CLT or CLT) were made immunogenic by coupling to protein carriers via the 3 and 17 positions, respectively. These immunogens were used to elicit polyclonal and monoclonal antibodies to CLAD and to clostebol. The antibodies were characterized in an enzyme immunoassay for sensitivity and specificity. Polyclonal antisera generated through position 17 reacted preferentially with 4-chlorotestosterone-17-acetate (clostebol acetate, CLTA), 4-chloro-epitestosterone (epi-clostebol, 17alpha-clostebol, 17alpha-CLT), and clostebol, whereas polyclonal antisera generated through the 3 position almost did not react with these derivatives. Interestingly, the monoclonal antibody generated through the 3 position recognized (35%) epi-clostebol. These results suggest that polyclonal antisera generated through the 17 position have a broad specificity profile and can be used to analyze by immunoassay methods urinary metabolites of clostebol acetate and thereby detect the illegal use of clostebol acetate in livestock farming.

Production and characterization of polyclonal antibodies to sulfamethazine and their potential use in immunoaffinity chromatography for urine sample pre-treatment.

An immunoaffinity chromatographic (IAC) method for isolating sulfamethazine (SMZ) from incurred urine samples was developed. This was achieved by (i) generating polyclonal antibodies that recognize equally well SMZ and its major urinary metabolites, (ii) evaluating in an ELISA procedure the influence of methanol, salt and pH on the antigen-antibody interaction in order to determine the optimum conditions for IAC and (iii) covalent coupling of the IgG fractions of anti-SMZ to CNBr activated Sepharose for the preparation of re-usable immunoaffinity columns, having a high capacity for SMZ (1900 ng SMZ mL-1 gel). For desorbing SMZ from the immunoaffinity column, different elution modes were evaluated, with 40% MeOH-0.1 mol L-1 HOAc-0.5 mol L-1 NaCl being the most efficient combination. Using the IAC column for processing SMZ spiked urine samples resulted in high recoveries, ranging from 92 to 100%. Because of the high cross-reactivity with the major metabolites of SMZ present in urine of treated animals, the antibodies show excellent properties for use in both IAC and ELISA. For the isolation and concentration of the parent drug and its major metabolites, the urine could be applied directly to the IAC column, without the time-consuming step of deconjugation. Moreover, the use of IAC prior to ELISA for the analysis of incurred urine samples showed good efficiency for the elimination of matrix interferences. Owing to the urine-tissue relationship, the urine concentrations can be used to predict the presence of the parent drug in tissues and so possible violations of the maximum residue limit (MRL) can be controlled.

Effect of microorganisms on rate of liquid extraction of ethanol from fermentation broths.

Liquid extraction is one means of removing metabolic products continuously during a fermentation and so reducing product inhibition. It is known that microbial organisms are attracted to liquid-liquid interfaces, and it is important for the design of extraction systems to establish if this has a detrimental effect on the rate of extraction. The extraction of ethanol from aqueous suspensions of yeast (Saccharomyces cerevisiae) using n- decanol is described in this paper. It was found that the presence of the yeast cells severely reduced the rate of ethanol extraction. The overall mass transfer coefficient was reduced from 5.0 x 10(-6) to 0.7 x 10(-6) m/s. This reduced overall mass transfer coefficient was unaffected by yeast concentration in the range 0.1-20 kg/m(3). The results are consistent with the yeast cells adsorbing to the interface in closely packed layers and preventing mass transfer by simply reducing the available interfacial area. Optical microscope observations confirmed that a yeast layer several cell diameters thick rapidly built up at the interface when a small decanol droplet was added to a yeast suspension.

Long-acting contraceptive agents: design of the WHO Chemical Synthesis Programme.

The great demand for improved long-acting injectable steroid contraceptives, particularly in developing countries, and the relative lack of interest from the pharmaceutical industry to develop such products stimulated WHO to launch a synthetic and screening programme to find improved, safe and acceptable injectable preparations. More than 210 esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) and levonorgestrel (D-(-)-13 beta-ethyl-17 alpha-ethynyl-17 beta-hydroxygon-4-en-3-one) have been prepared in university-based research laboratories situated mainly in developing countries, and then screened by NICHHD in animal models. The following three compounds, levonorgestrel butanoate, cyclopropylcarboxylate and cyclobutylcarboxylate, proved to be particularly long-acting when administered as microcrystalline suspensions. The overall strategy of this research and development programme is described.

Evaluation of chemical analysis for the determination of solasodine in Solanum laciniatum.

A detailed study of a method for solasodine analysis has been carried out and the suitability of chemical analysis for solasodine determination in plant material evaluated. A number of problems with the analytical isolation of solasodine and its subsequent colorimetric determination have been highlighted: oven drying of plant material greater than 100 degrees leads to solasodine loss; cell disruption of the dry plant material is required if complete and rapid extraction of solasodine is to take place; hydrolysis of plant extract residues in greater than 1 N acid leads to solasodine loss; the colorimetric procedure is more temperamental than past methods have indicated, especially with regard to the specificity of the reaction and the instability of the complex.

Injectable contraceptive synthesis: an example of international cooperation.

Since many contraceptives appropriate for use in developing countries are not of major interest to the pharmaceutical companies in developed countries, the World Health Organization has sponsored a program whereby contraceptives are developed outside the traditional pharmaceutical industry channels. This program might serve as a model for the develoment of other drugs or even pesticides.

Mexican plants and human fertility.

PIP: Synthetic steroids are obtainable cheaply and in abundance from sapogenins, substances originating from plants of the Discorea family. Some 40 years ago, Russell Marker, an American chemist, discovered this source, which grows abundantly in Mexican jungles and is now exploited and cultivated commercially. Today synthetic steroids prepared from extracts from a wide range of vegetable sources are used in the treatment of rheumatoid arthritis, allergies, inflammatory diseases, sterility, and various heart conditions, and form the basis of modern oral contraceptives. Nevertheless, oral contraceptives in current use are still fairly costly, and women have to be educated in their use. What is needed urgently is a cheaper contraceptive pill with a long-term effect, and research is continuing. For example, scientists from the People's Republic of China have reported significant anti-fertility effects associated with 2 substances, anordin and dinordin, prepared with steroids derived from the sisal plants Agave sisilana and Agave americana. These agents, whose anti-fertility properties have been confirmed by scientists in Sweden and the United States, constitute a new family of contraceptives with the great advantage of having to be taken only once or twice instead of 20 times per month necessary with the ordinary pill. Also from China, scientists have reported the effectiveness of gossypol as an orally administered male contraceptive, although gossypol is not a steroid. It may become, however, a leading candidate for a male contraceptive.^ieng

Chemical synthesis and bioassay of anordrin and dinordrin I and II.

The chemical synthesis of 2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-androstane-2 beta, 17 beta-diol dipropionate (Anordrin) and the corresponding diacetate is reported. Similarly, the preparation of the 2 alpha, 17 alpha-diethynyl-A-nor-5 alpha-estrane-2 beta, 17 beta-diol, its diacetate and dipropionate (Dinordrin I), along with the corresponding 2 beta-epimer (Dinordrin II) from 17 beta-hydroxy-A-nor-5 alpha=estran-2-one is described. In rat uterotrophic activity bioassay, the slope of ethynylestradiol differed significantly from the slopes of the other three compounds, thus vitiating potency estimates with this reference compound. Dinordrin I was 20 times more potent than Anordrin and considerably more potent then Dinordrin II. The single-dose oral antifertility effect in rats generally paralleled uterotrophic activity. Immediate postovulatory contraceptive effectiveness was assessed in adult cycling female baboons given two doses daily for 4 days. Both Anordrin and Dinordrin I showed antifertility activity worthy of further study. Moreover, a definite luteolytic effect, with depression of both plasma estrogen and progesterone levels, was observed with these two steroids.