Sodium bicarbonate, sodium carbonate, mono- and dibasic sodium phosphate, NaCl, BSA, Tween 20, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), hydrogen peroxide (H2O2), anhydrous citric acid, pentane, ethyl acetate, (3-glucuronidase, horseradish peroxidase (HRP)-testosterone, testosterone, and all other steroids were purchased from Sigma Chemical Co. (St. Louis, MO). [14C]Testosterone (specific activity 59.8 mCi/mmol) was purchased 97.9% pure in ethanol (NeN, Boston, MA). Rabbit polyclonal testosterone antibody was produced at UC Davis and directed to testosterone-6-CMO:BSA (VWR Scientific, San Francisco, CA). Anhydrous ethyl ether and methanol were purchased from Fisher Scientific (Fisher, Pittsburgh, PA). birth control yasmin
Experiments were run on feces from both white laboratory (Mus musculus) and field (Peromyscus maniculatus) mice, subsequently referred to as Mus and Peromyscus, respectively. Peromyscus were housed individually, and Mus were housed in pairs, in 7.5 X 11.5 X 5-inch polypropylene cages with a 14L:10D cycle. Animals had access to Purina Mouse Chow (Ralston-Purina, St. Louis, MO) and water ad libitum. All procedures and animal care were approved by the UC Davis Animal Care Committee.