OBJECTIVETo develop a method for detecting the topical concentration of hydrocortisone (HC) in the subcutaneous adipose of rats using microdialysis sampling technique and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS).

METHODSTopical samples were collected by applying the probe into the subcutaneous adipose of rats, with alcohol (5%)-ringers solution as the perfusion solution. A LC-MS/MS method was established for detecting the HC concentration in the dialysates.

RESULTSThe protonated precursor to produce ion transitions monitored for HC was m/z 363.2→121.1. The calibration curve was linear over the range of 0.5-1000 ng/ml, with the intra- and inter-day precision and accuracy within ∓15%, and no significant matrix effect was noted. The in vivo recovery of the probe was about 59%.

CONCLUSIONA selective and sensitive method has been successfully established for the on-line HC detection in the subcutaneous adipose of rats.

Administration, Cutaneous ; Animals ; Chromatography, Liquid ; methods ; Hydrocortisone ; administration & dosage ; pharmacokinetics ; Male ; Microdialysis ; methods ; Rats ; Rats, Wistar ; Subcutaneous Fat ; chemistry ; metabolism ; Tandem Mass Spectrometry ; methods

The aim of the present study was to investigate the relationship of plasma resistin levels with determinants of the metabolic syndrome (MetS) and anthropometric parameters in healthy Korean subjects. Plasma resistin levels were determined in 276 subjects. In subjects with MetS, the plasma resistin levels were not significantly increased compared to those without MetS (8.3+/-4.3 ng/mL vs. 8.5+/-3.6 ng/mL, respectively, P=0.84). In addition, the plasma resistin levels were not correlated with the body mass index, the waist circumference, homeostasis model assessment-insulin resistance (HOMA-IR), fasting plasma glucose or insulin levels. However, the plasma resistin levels were positively correlated with the abdominal subcutaneous fat (r=0.18, P<0.01) in all subjects and correlated with TNF alpha(r=-0.16, P<0.05) and hsCRP (r=0.15, P<0.05) in subjects without MetS but not with MetS. With multiple linear regression analysis, these linear associations remained to be significant. The results of this study show that plasma resistin levels in humans were not associated with markers of insulin resistance, obesity or other determinants of the MetS.
Adult ; Aged ; Anthropometry ; Biological Markers/blood ; Blood Glucose/analysis ; Body Mass Index ; C-Reactive Protein/metabolism ; Female ; Humans ; Insulin/blood ; *Insulin Resistance ; Male ; Metabolic Syndrome X/diagnosis/*metabolism ; Middle Aged ; Obesity/diagnosis/metabolism ; Resistin/*blood ; Subcutaneous Fat/*chemistry ; Tumor Necrosis Factor-alpha/metabolism