Low Free Testosterone Is Associated with Hypogonadal Signs and Symptoms in Men with Normal Total Testosterone.

Context: During aging, total testosterone (TT) declines and SHBG increases, resulting in a greater decrease in calculated free T (cFT). Currently, guidelines suggest using TT to diagnose androgen deficiency and to reserve cFT only for men with borderline TT.

Objective: Our objective was to investigate if either low cFT or low TT is more strongly associated with androgen-related clinical endpoints.

Associations between sex steroids and the development of metabolic syndrome: a longitudinal study in European men.

Context: Low testosterone (T) has been associated with incident metabolic syndrome (MetS), but it remains unclear if this association is independent of sex hormone binding globulin (SHBG). Estradiol (E2) may also be associated with MetS, but few studies have investigated this.

Objective: To study the association between baseline sex steroids and the development of incident MetS and to investigate the influence of SHBG, body mass index (BMI) and insulin resistance on this risk.

Purification and characterization of a novel carbonyl reductase isolated from Rhodococcus erythropolis.

During growth on n-tetradecane a novel NADH-dependent carbonyl reductase is induced in the Gram-positive bacterium Rhodococcus erythropolis (Peters, P., Zelinski, T. and Kula, M.

Modification of L-isoleucyl-tRNA synthetase with L-isoleucyl-bromomethyl ketone. The effect of the catalytic steps.

The rapidly reacting cysteine-sulfhydryl group of L-isoleucyl-tRNA synthetase has been specifically alkylated with L-isoleucyl-bromomethyl ketone [Rainey, P., Holler, E. & Kula, M.

Labelling of L-isoleucine tRNA ligase from Escherichia coli with L-isoleucyl-bromomethyl ketone.

L-Isoleucine: tRNA ligase from Escherichia coli could be irreversibly inactivated by L-isoleucyl-bromomethyl ketone but not by L-isoleucyl-chromethyl ketone. The inactivation rate exhibited a saturation concentration dependence typical for an affinity reagent. L-Isoleucine provided 100% protection against inactivation at saturating concentration, whereas ATP, AMP, and pyrophosphate offered partial protection and tRNAIle, no protection.