Animals and Experimental Treatments
Pregnant Western spotted skunks (Spilogale putorius la-tifrons) that had bred in the wild were obtained from a USDA-licensed dealer in Oregon. Skunks were individually housed, fed Purina (Ralston-Purina, St. Louis, MO) Ferret Chow and given water ad libitum, and maintained on a natural photoperiod. Animals were killed throughout the preimplantation stages of pregnancy by an overdose of sodium pentobarbital. Blood samples were collected into hep-arinized vacuum tubes prior to death by cardiac puncture. The plasma was stored at -20°C until time of hormone assay. Uteri were removed, flushed with sterile 0.05 M PBS to recover blastocysts, flash frozen in liquid propane, weighed, and stored at -80°C. Classification of the stage of pregnancy (delay, early, and late blastocyst activation) was determined by measuring embryo diameter as previously described. ampicillin antibiotic
Beginning in early january, 33 skunks were divided into six treatment groups. Animals were anesthetized with sodium pentobarbital, bilaterally ovariectomized, and allowed to recover. All animals received daily injections of penicillin (60 000 U). Six skunks were given daily injections of 0.5 mg PRL dispersed in 5% beeswax and sesame oil for 6 consecutive days beginning 3 days after ovariectomy.