Evaluation of progesterone and 20-oxo-progestagens in the plasma of Asian (Elephas maximus) and African (Loxodonta africana) elephants

✍ Scribed by Franz Schwarzenberger; Günter Strauss; Hans-O. Hoppen; Willem Schaftenaar; Steph J. Dieleman; Wolfgang Zenker; Olivier Pagan

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 122 KB
• Volume: 16
• Category: Article
• ISSN: 0733-3188
• DOI: 10.1002/(sici)1098-2361(1997)16:5<403::aid-zoo3>3.0.co;2-e

✦ Synopsis

The corpus luteum of African elephants produces high amounts of 5α-reduced progesterone metabolites (5α-pregnane-3,20-dione and 5-α-pregnane-3α-ol-20one), whereas progesterone itself is quantitatively less important, and plasma levels of progesterone during the estrous cycle in elephants are considerably lower than those of other mammals. The objective of this study was to compare the concentration of progesterone in plasma of Asian and African elephants as determined by specific progesterone assays with those of total immunoreactive progestagens containing a 20-oxo-group (20-oxo-P). These metabolites were determined by an enzyme immunoassay using an antibody against 5-α-pregnane-3β-ol-20-one, 3HS:BSA. Plasma of non-pregnant Asian (n = 4) and African (n = 4) elephants was collected at weekly intervals for periods of 8-15 months and at random intervals during pregnancy in one Asian elephant. High-performance liquid chromatography separation of plasma samples of both species demonstrated that in the 20-oxo-P assay, 5α-pregnane-3,20-dione makes up ~60% of the total immunoreactive material. The progesterone and 20-oxo-P values during the estrous cycle showed a parallel pattern and were significantly correlated (P < 0.001; Asian: r = 0.80; y = 3.76 × -0.10; African: r = 0.75; y = 2.66 × -0.08). Progesterone and 20-oxo-P values in Asian and African elephants were <0.15 ng/ml during the follicular phase (weeks -4 to 0) of the estrous cycle; progesterone values during the luteal phase (weeks 2-9) were 0.60 ± 0.03 and 0.53 ± 0.03 ng/ ml, and the 20-oxo-P values were 2.19 ± 0.16 and 1.48 ± 0.12 ng/ml, respec-