Determination of Cortisol concentration in human erythrocytes

1983 ◽  
Vol 134 (1-2) ◽  
pp. 143-153 ◽  
Author(s):  
Hiramatsu Ryoji
Keyword(s):  
Cortisol Concentration ◽  
Human Erythrocytes

scholarly journals Simultaneous Determination of Cortisol and Cortisone from Human Serum by Liquid Chromatography-Tandem Mass Spectrometry

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Sanghoo Lee ◽  
Hwan-Sub Lim ◽  
Hye-Jin Shin ◽  
Seol-A Kim ◽  
Jimyeong Park ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Ammonium Acetate ◽  
Cortisol Concentration ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Cortisol Ratio

A fast, sensitive, and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was validated and then the levels of cortisol and cortisone from sera of healthy adults were determined by the LC-MS/MS method. One hundredμL of serum sample was directly extracted by adding 2 mL ethyl acetate, followed by chromatographic separation on a C18 column with a mobile phase consisting of 5 mM ammonium acetate and methanol (25 : 75, v/v). The precision, accuracy, and average recovery of the method were 1.5–5.3%, 95.4–102.5%, and 96.4% for cortisol, and 1.9–6.0%, 89.2–98.8%, and 79.9% for cortisone, respectively. The method was linear from 1.0 to 500.0 ng/mLr2=0.999for cortisol and 2.5 to 100.0 ng/mLr2=0.998for cortisone. The limits of detection (LOD) and quantification (LOQ) were 0.2 and 1.0 ng/mL for cortisol, and 1.0 and 2.5 ng/mL for cortisone, respectively. The average cortisol concentration (133.9±63.7 ng/mL) of samples collected between 9:00 and 11:00 a.m. was higher approximately 4.4 times than that of cortisone (30.5±10.7 ng/mL)P<0.0001. The average cortisone/cortisol ratio was 0.225. Therefore, the LC-MS/MS method may be useful for the diagnosis of some adrenal diseases and the assessment of 11β-hydroxysteroid dehydrogenase (11β-HSD) activity in clinical laboratories.

scholarly journals Determination of the steady-state turnover rates of the metabolically active pools of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate in human erythrocytes

1989 ◽  
Vol 259 (3) ◽  
pp. 893-896 ◽  
Author(s):  
C E King ◽  
P T Hawkins ◽  
L R Stephens ◽  
R H Michell
Keyword(s):  
Steady State ◽  
Rate Constants ◽  
Human Erythrocytes ◽  
Turnover Rates ◽  
Metabolic Fluxes ◽  
Metabolic Pool ◽  
Phosphatidylinositol 4 ◽  
Kinetics Of ◽  
Phosphate Groups

When intact human erythrocytes are incubated at metabolic steady state in a chloride-free medium containing [32P]Pi, there is rapid labelling of the gamma-phosphate of ATP, followed by a slower labelling of the monoester phosphate groups of phosphatidylinositol 4-phosphate (PtdIns4P) and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] [King, Stephens, Hawkins, Guy & Michell (1987) Biochem. J. 244, 209-217]. We have analysed the early kinetics of the labelling of these phosphate groups, in order to determine: (a) the steady-state rates of the interconversions of phosphatidylinositol, PtdIns4P and PtdIns(4,5)P2; and (b) the fractions of the total cellular complement of PtdIns4P and PtdIns(4,5)P2 that participate in this steady-state turnover. The experimental data most closely fit a pattern of PtdIns4P and PtdIns(4,5)P2 turnover in which one-quarter of the total cellular complement of each lipid is in the metabolic pool that participates in rapid metabolic turnover, with rate constants of 0.028 min-1 for the interconversion of PtdIns and PtdIns4P, and of 0.010 min-1 for the PtdIns4P/PtdIns(4,5)P2 cycle. These rate constants represent metabolic fluxes of approx. 2.1 nmol of lipid/h per ml of packed erythrocytes between PtdIns and PtdIns4P and of approx. 5.7 nmol/h per ml of cells between PtdIns4P and PtdIns(4,5)P2.

Highly Selective Fluorescence Determination of the Hematin Level in Human Erythrocytes with No Need for Separation from Bulk Hemoglobin

2016 ◽  
Vol 88 (7) ◽  
pp. 3935-3944 ◽  
Author(s):  
Lijuan Ji ◽  
Li Chen ◽  
Ping Wu ◽  
Dominic F. Gervasio ◽  
Chenxin Cai
Keyword(s):  
Human Erythrocytes ◽  
Fluorescence Determination

Studies on the "labile-bound" glucose compartment in erythrocytes: studies on Psammomys obesus (sand rat) and preliminary studies on human erythrocytes.

1985 ◽  
Vol 31 (7) ◽  
pp. 1219-1221 ◽  
Author(s):  
M Halperin ◽  
J H Adler
Keyword(s):  
Glucose Oxidase ◽  
Glucose Concentration ◽  
Human Erythrocytes ◽  
Psammomys Obesus ◽  
Sand Rat ◽  
Fluid Compartment ◽  
Fast Kinetic ◽  
Fluid Compartments

Abstract Enzymatic (glucose oxidase) measurement of glucose concentration in the fluid compartment of Psammomys erythrocytes (Gfe) and of its concentration in the fluid compartment of blood plasma (Gfp) gives the ratio (mean +/- SD): Gfe/Gfp = 1.50 +/- 0.43 (n = 12, 23 degrees C). However, when we added 3H-labeled glucose (G*) in vitro to the whole blood, the ratio after 2 min was G*fe/G*fp = 0.90 (SD 0.11) and after 5 min G*fe/G*fp = 0.97 (SD 0.12). These calculations were based on previous determination of the fractional volumes of the fluid and non-fluid compartments in Psammomys blood. The results suggest that there is more than one compartment of measurable glucose in Psammomys erythrocytes. Glucose undergoes a fast free transfer between the plasma and the erythrocyte fluids, and a much slower transmission to another measurable compartment in the erythrocyte, where it is loosely bound to other molecules. This loosely bound glucose does not participate in the fast kinetic transmission across the erythrocyte membrane, but it is measurable by the glucose-oxidase-based method. Preliminary studies on human erythrocytes lead to similar conclusions.

New Method for Determination of Aminolaevulinate Dehydratase Activity of Human Erythrocytes as an Index of Lead Exposure

1974 ◽  
Vol 20 (10) ◽  
pp. 1287-1291 ◽  
Author(s):  
Katsumaro Tomokuni
Keyword(s):  
Enzyme Activity ◽  
Ion Exchange ◽  
Present Method ◽  
Aminolevulinic Acid ◽  
Usual Method ◽  
Human Erythrocytes ◽  
New Method ◽  
Ion Exchange Column ◽  
Dehydratase Activity

Abstract I describe a new method for measurement of aminolaevulinate dehydratase (EC 4.2.1.24) activity of human erythrocytes. In this method, the amount of substrate δ-aminolevulinic acid consumed (instead of the amount of porphobilinogen formed) is determined colorimetrically. In the incubation mixture, the δ-aminolevulinic acidpyrrole produced by the condensation of δ-aminolevulinic acid with ethyl acetoacetate is separated from porphobilinogen by extraction with ethyl acetate, without resorting to ion-exchange column chromatography. The pyrrole-containing extract is treated with a modified Ehrlich's reagent. Activity of the enzyme is expressed as micromoles of δ-aminolevulinic acid consumed per minute per liter of erythrocytes. Enzyme activity is more accurately estimated by the present method than by the usual method in which porphobilinogen is measured.

Improved determination of cytochrome b5 in human erythrocytes.

1984 ◽  
Vol 30 (8) ◽  
pp. 1344-1347 ◽  
Author(s):  
A Kaftory ◽  
E Hegesh
Keyword(s):  
Spectrophotometric Method ◽  
Cytochrome B5 ◽  
High Sensitivity ◽  
Human Erythrocytes ◽  
Healthy Individuals ◽  
Mean Values

Abstract A sensitive, precise enzymic/spectrophotometric method for determining cytochrome b5 in small amounts of blood is described. Mean values for healthy individuals, ages 20 to 70 years, were 0.26 (SD 0.03) mumol per liter of erythrocytes or 0.87 (SD 0.14) nmol per gram of hemoglobin. We believe the assay is preferable to methods described hitherto, primarily because of its high sensitivity.

Sign in / Sign up

Export Citation Format

Share Document