An enzyme-linked immunosorbent assay (ELISA) for human sex hormone-binding globulin

An enzyme-linked immunosorbent assay (ELISA) of the "sandwich-type" for sex hormone binding globulin (SHBG) has been developed. A rabbit anti-SHBG antibody (RAb) is immobilized to the microtitre plate. After incubation with standards and samples a second monospecific rabbit anti-SHBG antibody, labelled with alkaline phosphatase is added (RAb). Following further washing substrate is added, colour developed and the plate read at 405 nm wavelength on a standard ELISA plate reader. The assay is not influenced by the presence of steroids at the binding site, and shows good agreement to SHBG binding capacity assay and commercially available IRMA. Its sensitivity, specificity and precision allows its use in the routine laboratory. The SHBG ELISA has been used to measure SHBG concentrations in sera of normal men, women, pregnant women, and women receiving high-dose medroxyprogesterone acetate as a treatment of metastatic breast cancer.     

A preparative and analytical microscale procedure for nonhistone chromosomal proteins

A nonhistone chromosomal protein (NHC proteins) fractionation scheme is described, which enables us to obtain separations of these proteins on a preparative scale in milligram quantities. The following experimental procedure was applied: differential dissociation of chromatin, cation exchange chromatography on Bio-Rex 70, preparative fractionation of those NHC proteins which are not absorbed on Bio-Rex 70, and determination of the isoelectric point range in a zone convection-focusing apparatus. In a subsequent continuous (0–40% acrylamide) microgradient SDS-gel electrophoresis system, we could detect more than 440 different NHC protein components of cow's udder.     

16 alpha-iodo-3,17 beta-estradiol: a stable ligand for estrogen receptor determinations in tissues with high 17 beta-hydroxysteroid dehydrogenase activity

Recently, the successful synthesis of radioiodinated 16 alpha-iodo-3,17 beta-estradiol-[125I] [125I]E2 was reported [1]. This new ligand has similar binding characteristics to the estrogen receptor (ER) [2-5] as the currently used tritium labeled estradiol [3H]E2. However, it offers several advantageous features: (a) high specific activity (theoretically 2,000 Ci/mmol) [1]; (b) minor problems with radioactive waste due to its short half life and (c) the possibility of simultaneous determination of ER and progesterone receptors (PgR) by double labeling with [125I]E2 and [3H]R5020 [6, 7]. As we are presently trying to determine ER and PgR in human placental cytosols we were interested in the stability of different labeled estrogens under the conditions of ER-assay. Placental cytosols [8] as well as cytosols of other tissues such as endometrium [9, 10], ovary [11] or mammary carcinomas [12] have been reported to contain significant amounts of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity. Conversion of labeled estradiol to estrone during incubation for ER-quantification would diminish the amount of labeled estradiol thus leading to errors in ER-concentrations, as estrone has only about 10% of estradiol's binding activity [13].     

Comparison of nonhistone chromosomal proteins from neuronal and glial chromatin by isoelectric focussing and microdisc electrophoresis.

The present study describes optimal conditions for preparative fractionation of nonhistone chromosomal proteins from neuronal and glial nuclei.We have detected about 1200 nonhistone chromosomal proteins. Microgels of glial origin contained 20% more protein bands than those of neuronal origin. However, neuronal bands prevailed clearly in the acidic respectively in the high-molecular range. Amino acid analysis confirmed the observed heterogeneity.