Thesis Title

Progesterone and Prolactin Profiles of the Female Asian Elephant (Elephas Maximus)

Date of Graduation

Spring 1993

Degree

Master of Science in Biology

Department

Biology

Committee Chair

Thomas Tomasi

Subject Categories

Biology

Abstract

Serum progesterone and prolactin concentrations were determined daily (around estrus), weekly (throughout the estrous cycle), and bimonthly (during gestation) in 8 female Asian elephants. A total of 18 estrous cycles with 4 resulting in conception are described. Early gestational values are shown in 4 animals, with 2 animals followed to term. Serum progesterone concentrations ranged from 10 pg/ml to 1014 pg/ml. Serum prolactin concentrations ranged from .77 ng/ml to 1020 ng/ml. Cycle length was determined as the time between initial, sustained progesterone rises from basal levels. This research supports the 13-16 week estrous cycle length determined in previous studies. Serum progesterone was elevated above 100 pg/ml for 8-10 weeks of the estrous cycle. Progesterone assays showed a mean drop of 87.1 ± 18.2 (mean ± SEM) pg/ml after the initial progesterone rise during estrus. Progesterone levels then remained elevated to rise during diestrus or gestation up to values of 1014 pg/ml. Throughout gestation, progesterone values fluctuated greatly among and within individuals, with levels being maintained above 100 pg/ml until 3 days prepartum. At this time, progesterone levels dropped below 50 pg/ml and remained at this level postpartum. Prolactin levels fluctuated below 10 ng/ml during estrus, with one spike above 10 ng/ml occurring on day one of progesterone rise. Serum prolactin showed low level fluctuations throughout the estrous cycle, with spikes above 10 ng/ml in weeks one and two only (spikes were noted in 3 of 18 cycles). Gestational prolactin levels climbed slowly for the first 3-4 months, reaching significantly higher levels by the fifth month. Prolactin levels remained elevated to term. This study indicates that progesterone and prolactin may be utilized to assess reproductive status (estrous cycle length, estrus predictin, pregnancy) in female Asian elephants.

Copyright

© Melissa Ann Carden

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