Gdf 8 myostatin quantikine elisa kit

Although this study included premenopausal and postmenopausal women, the timing of blood collection was not determined by the menstrual cycle. Fasting blood samples were collected for determining the serum levels of triglycerides, HDL cholesterol, LDL cholesterol, plasma glucose, HbA1c, C-reactive protein (CRP), and immunoreactive insulin (IRI). Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated based on the blood insulin level after fasting early in the morning [HOMA-IR = (IRI × fasting plasma glucose)/405].
Blood samples were stored at −80°C, and both adipokine and myokine levels were measured according to the manufacturer’s instructions. Serum adiponectin and leptin levels as adipokines were measured using the human Quantikine ELISA Kit (R&D Systems, Minneapolis, MN, USA). Serum myostatin and irisin levels as myokines were measured using the GDF-8/Myostatin Quantikine ELISA Kit (R&D Systems, Minneapolis, MN, USA) and human EIA Kit (Phoenix Pharmaceuticals Inc., Burlingame, CA, USA), respectively. The intra- and inter-assay coefficients of variation were 2.5–4.7% and 5.8–6.9% for adiponectin, 3.0–3.3% and 3.5–5.4% for leptin, 1.8–5.4% and 3.6–6.0% for myostatin, and < 10% and < 15% for irisin, respectively.

Blood was collected by terminal cardiac puncture, and serum was analyzed for MSTN protein using the GDF-8/Myostatin Quantikine ELISA kit (R&D Systems, Minneapolis, MN, USA). Serum samples were activated as described in the manufacturer’s protocol, with the exception that the final activated serum sample had an additional 1:2 dilution in calibrator diluent before assaying.

Patient medical history and clinical characteristics were collected from medical records. Fasting blood was analyzed to determine glucose (GLU), glycosylated hemoglobin (HbA1c), and immunoreactive insulin (IRI) levels. We evaluated the endogenous effect of insulin resistance on vascular function. Insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR). HOMA-IR was calculated as follows: HOMA-IR = (IRI × fasting plasma GLU) / 405. Additionally, we measured the plasma levels of myokines, adiponectin, leptin, and irisin. Blood samples were stored at − 80 °C, and both myokine and adipokine levels were measured according to the manufacturer’s instructions. Serum myostatin and irisin levels as myokines were measured using the GDF-8/Myostatin Quantikine ELISA Kit (R&D Systems, Minneapolis, MN, USA) and human EIA Kit (Phoenix Pharmaceuticals Inc., Burlingame, CA, USA). Serum adiponectin and leptin levels as adipokines were measured using the human Quantikine ELISA Kit (R&D Systems, respectively. Minneapolis, MN, USA). The intra- and inter-assay coefficients of variation were 2.5–4.7% and 5.8–6.9% for adiponectin, 3.0–3.3% and 3.5–5.4% for leptin, 1.8–5.4% and 3.6–6.0% for myostatin, and < 10% and < 15% for irisin, respectively.