DETERMINATION OF LUTEINIZING HORMONE IN BOVINE BLOOD BY RADIOLIGAND RECEPTOR ASSAY AND COMPARISON WITH RADIOIMMUNOLOGICAL EVALUATION

1978 ◽  
Vol 87 (2) ◽  
pp. 268-278 ◽  
Author(s):  
D. Schams ◽  
C. Menzer
Keyword(s):  
Luteinizing Hormone ◽  
Close Correlation ◽  
Exchange Chromatography ◽  
Bovine Blood ◽  
Serum Samples ◽  
Bovine Plasma ◽  
Receptor Assay ◽  
C 50 ◽  
Radioligand Receptor Assay

ABSTRACT A sensitive and specific radioligand receptor assay (RRA) using rat testis homogenate as the receptor source is described for measurement of luteinizing hormone (LH) in bovine blood. Interfering and non-specific substances in blood were removed by means of ion-exchange chromatography on CM-Sephadex C-50. Criteria of validation such as recovery of added LH to plasma or serum, reproducibility, and specificity gave good results. Inhibition curves obtained with bovine plasma and serum were parallel to those obtained with the bovine standard preparation. The range of the dose-response curve was between 0.5–20 ng of bovine LH. The pattern of LH concentrations in purified serum samples under different physiological conditions such as during the oestrous cycle and after administration of GnRH showed a very close correlation whether measured by means of radioimmunoassay (RIA) or receptor assay. Values of RRA-LH were consistently higher than those of RIALH. Thus the lower the RIA-LH levels, the more pronounced were the discrepancies between results of both assay systems. The mean ratio of RRA-LH/RIA-LH for basal levels (less than 1 ng RIA-LH/ml plasma) was 17.8 as compared to a mean ratio for higher peak values (more than 20 ng RIA-LH/ml plasma) of only 1.2.

APPLICATION OF A RADIOLIGAND RECEPTOR ASSAY FOR DETERMINATION OF LUTEINIZING HORMONE IN HUMAN SERUM

1976 ◽  
Vol 81 (1) ◽  
pp. 54-72 ◽  
Author(s):  
F. A. Leidenberger ◽  
R. Willaschek ◽  
V. G. Pahnke ◽  
L. E. Reichert
Keyword(s):  
Human Serum ◽  
Precipitation Method ◽  
Serum Samples ◽  
Serum Lh ◽  
Fractionation Procedure ◽  
Receptor Assay ◽  
Menopausal Women ◽  
Post Menopausal ◽  
Radioligand Receptor Assay ◽  
Lh Releasing Hormone

ABSTRACT A sensitive, specific and economic radioligand receptor assay is described for measurement of LH in human serum (RRA-LH). By means of ethanol fractionation or (NH4)2SO4-precipitation serum can be prepared for LH-quantitation and tested in the RRA-LH without interference of a nonspecific inhibiting substance present in untreated serum from various human sources. Treatment of serum with 8 % ethanol separates nonspecific inhibiting substances from LH, the latter remaining in the supernatant at this ethanol concentration. The criteria of specificity are examined. The results of experiments designed to produce evidence for or against specificity suggest specificity of the RRA-LH. Recoveries, as estimated by administration of [125I]hLH and unlabelled hLH to untreated serum samples are shown to be between 80 and 95 % for the ethanol fractionation procedure and between 65 and 75 % for the (NH4)2SO4-precipitation method. The ethanol fractionation procedure is preferred for routine serum-LH determination because of its simplicity, speed and higher recoveries. Ethanol-treated sera from post-menopausal women show, on average, higher RRA-LH concentrations than ethanol-treated sera from young women. RRA-LH values are consistently higher than LH-values found by radioimmunoassay (RIA-LH). The LH-concentrations in sera from two menstrual cycles and from two LH-releasing hormone tests are measured by RRA-LH and by RIA-LH. Similarities and discrepancies of the LH-profiles found by the two assay systems are described.

Rapid analysis of bilirubin in neonatal serum. I. The binding of bilirubin to albumin.

1979 ◽  
Vol 25 (9) ◽  
pp. 1608-1612 ◽  
Author(s):  
K C Lu ◽  
K M Gooding ◽  
F E Regnier
Keyword(s):  
Serum Proteins ◽  
Binding Capacity ◽  
Gel Permeation Chromatography ◽  
Exchange Chromatography ◽  
Serum Samples ◽  
Binding Characteristics ◽  
Quenching Analysis ◽  
Gel Permeation ◽  
Bilirubin Binding

Abstract Evaulation of the severity of jaundice in the neonate may be determined by measuring the reserve binding capacity of serum proteins for free bilirubin. Determination of protein-bound bilirubin has been labor intensive, necessitating multiple runs on gel-permeation chromatography columns or, more recently, enzyme assays or fluorescence quenching analysis. We present a method for quantitation of free bilirubin and of bilirubin-binding capacity of serum by liquid chromatography. A gel-permeation column binds free bilirubin while allowing passage and quantitation of protein-bound bilirubin. Subsequent injection of a desorbing agent releases the adsorbed bilirubin from the column, permitting quantitation of free bilirubin. Bound and free serum bilirubin may be determined directly in less than 15 min using 10 microL of serum. The binding of bilirubin to neonatal serum is seen to be quite different from the binding to adult serum. Ion-exchange chromatography of adult and neonatal serum samples shows that their protein profiles are radically different. This difference probably accounts for the binding characteristics.

Determination of creatinine in serum and urine by cation-exchange high-pressure liquid chromatography

1991 ◽  
Vol 37 (4) ◽  
pp. 563-565 ◽  
Author(s):  
Aimo Harmoinen ◽  
Pekka Sillanaukee ◽  
Hannu Jokela
Keyword(s):  
Cation Exchange ◽  
Regression Line ◽  
Hplc Method ◽  
Exchange Chromatography ◽  
Enzymatic Method ◽  
Serum Samples ◽  
Creatinine Concentration ◽  
Enzymatic Determination ◽  
Serum And Urine

Abstract We describe an HPLC method for quantifying creatinine, separating the analyte from other compounds in serum and urine by cation-exchange chromatography and measuring its absorbance at 234 nm. The precision of the method (CV) varied from 2.9% (mean creatinine concentration, 31 mumol/L) to 1.7% (361 mumol/L) within a series of assays and from 3.9% (34 mumol/L) to 2.4% (391 mumol/L) between series. A comparison with the Jaffé method, as performed with a Technicon SMA analyzer, gave the regression line yHPLC = 1.00xJaffé - 12.0 (n = 141, r = 0.998, and Syx = 19). Results also are comparable with those of an enzymatic method, if the enzymatic method is standardized with a serum-based standard when serum samples are measured. An aqueous standard has to be used for enzymatic determination of creatinine in urine.

CHROMATOGRAPHIC HETEROGENEITY OF IMMUNOREACTIVE LUTEINIZING HORMONE RELEASING HORMONE IN BLOOD FROM THE RABBIT, SHEEP AND RAT

1974 ◽  
Vol 62 (2) ◽  
pp. 333-340 ◽  
Author(s):  
S. L. JEFFCOATE ◽  
D. T. HOLLAND
Keyword(s):  
Luteinizing Hormone ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Serum Samples ◽  
Blood Samples ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Rh

SUMMARY Serum samples from rabbits, sheep and rats containing immunoreactive luteinizing hormone releasing hormone (LH-RH) have been extracted and fractionated by ion exchange chromatography on carboxymethylcellulose followed by radioimmunoassay of the fractions. Control experiments showed that the extraction and chromatographic procedures did not alter the mobility of synthetic LH-RH. Four immunoreactive components of circulating LH-RH in blood samples from various species at various times were identified on CM-cellulose columns. One of these had a mobility identical with that of synthetic LH-RH; of the others, two were eluted before and one after synthetic LH-RH. The nature, site of formation and possible significance of the extra components are discussed.

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