Quantifying Oxytocin in Bodily Fluids

Previous research has used un-extracted CSF samples to estimate OT concentration in rodents [35] (link), in primates [22] (link), , in human neonates [36] (link), and vasopressin concentration in humans [3] (link). We also used this approach in the present study. All samples were assayed for OT by enzyme-linked immunosorbent assay (ELISA) using a commercially available kit (Enzo Life Sciences, Farmingdale, NY). The kits have a sensitivity of 11.7 pg/mL with less than 0.2% cross-reactivity with vasopressin. Instructions supplied with the OT ELISA kit were followed without modification, and CSF samples were directly assayed while plasma was extracted prior to testing [27] (link), [37] (link). Plasma was extracted using acetone and ether, and dried down using a Savant speedvac as outlined by Enzo Life Sciences technical support. Plasma samples were then rehydrated in assay buffer prior to testing. We examined serial dilutions and only extracted plasma produced linear concentration estimates (preliminary data).