Acute phase proteins in post-pubertal mice. A: Serum amyloid A and haptoglobin mRNA expression patterns in pre-pubertal, pubertal and post-pubertal mice. The X-axis represents time points (weeks) in female and male mice, and the Y-axis represents relative intensity ratios. B: Serum amyloid A and haptoglobin protein levels in post-pubertal C57BL/6 mice. Serum amyloid A levels in 24- to 28-week-old C57BL/6 mice. Serum samples (1:200) along with known standards were assayed in 96-well ELISA plates. The concentrations of the test samples were determined from the standard curve by multiplying the interpolated values by the dilution factor (n = 10/sex: male vs. female [μg/ml mean ± SE]: 77.48 ± 25.26 vs. 0.38 ± 0.12; p = 0.009). The working assay range was 11.8-190 μg/ml. Normal serum levels of SAA are generally less than 20 μg/ml. Serum haptoglobin levels were assayed using a colorimetric assay. Normal murine haptoglobin levels range from 0–0.1 mg/ml, and these increase in the acute phase to 0.3–2.0 mg/ml. The assay has a sensitivity of 0.05 mg/ml haptoglobin. (n = 10/sex: male vs. female [mg/ml mean ± SE]: 0.578 ± 0.059 vs. 0.254 ± 0.013; p = 0.00004).