Twenty-Third Annual Meeting and Symposium of the
Desert Tortoise Council, April 3-5, 1998
Abstracts

Blood samples were collected by jugular puncture at monthly intervals from April to October from 20 adult male and 30 adult female desert tortoises. The tortoises were maintained in pens 15 m x 30 m with natural vegetation and small artificial sod plots at the Desert Tortoises Conservation Center, Las Vegas, Nevada. Water and alfalfa hay were supplemented. Progesterone, testosterone, estradiol, thyroid hormone, corticosterone and androstenedione and lipids and calcium were analyzed in all of the plasma samples. Part of this study was published earlier (Rostal et al. Herp. Monogr. 8:72-82, 1994). Plasma corticosterone in male tortoises ranged from 0.580 ng/ml to 5.990 ng/ml and showed a significant seasonal pattern. Mean corticosterone in males was significantly higher in August and September than in April, May and June. Female values ranged from 0.200 ng/ml to 4.080 ng/ml. The mean monthly values for female tortoises were significantly lower than that of the males in every month, and the seasonal pattern was different. Peak values in the females occurred in April, and lower mean values were seen for all other months. Plasma androstenedione in males showed a somewhat similar cycle in that higher values were seen in August through October. Female samples are currently being analyzed and will be presented.