Development and Validation of a Fecal Testosterone Biomarker: MATERIALS AND METHODS(6)

MATERIALS AND METHODS(6)

Radiolabeled Testosterone Metabolism

Radiolabeled trace was used to determine how mice metabolized and excreted testosterone. Mus (n = 3) and Pero-myscus (n = 3), ages 3-24 mo, were injected i.p. with [14C]testosterone. Animals were caged in stainless steel metabolic chambers for separation of urine and feces; mice had access to food and water ad libitum. Buy Advair Diskus Online

To prepare for injection, [14C]testosterone was transferred to a 5-ml serum vial (Fisher), evaporated under nitrogen, and reconstituted with 3 ml sterile 0.9% saline containing 3 mg cold testosterone. A 50-^l aliquot was removed with a 1/2-cc insulin syringe (Becton-Dickinson, Franklin Lakes, NJ), transferred to a scintillation vial, and counted on the LSC. The injectate was measured at 667 000 dpm/50 pl and stored at room temperature to prevent precipitation. Urine and fecal samples were collected prior to injection of radiolabel to obtain baseline levels. Peromyscus were injected i.p. with 50 pl of prepared in-jectate and placed in metabolic chambers for sample collection. In Mus the injection was increased to 70 pi In both cases, identical injectates were placed into three scintillation vials, radioactivity was determined, and the average was taken to determine the dpm [14C]testosterone injected into each mouse.

This entry was posted in Testosterone and tagged Biomarker, Mus musculus, Peromyscus maniculatus, Testosterone.