Patterns of urinary and fecal steroid excretion during the ovarian cycle and pregnancy in the African elephant (Loxodonta africana)

The aims of the present study were to (i) determine the relative abundance of the Sa-reduced progestins 5 alpha-pregnane-3-ol-20-one (5 alpha-P-30H) a nd 5 alpha-dihydroprogesterone (5 alpha-DHP) and progesterone (P4) in Afric an elephant feces and to establish improved fecal progestin assays for moni toring ovarian function; and (ii) describe longitudinal profiles of urinary and fecal progestin and estrogen metabolites during pregnancy. Matched uri ne and fecal samples were collected weekly from six adult females throughou t 18 nonfertile cycles and two complete pregnancies (89 and 93 weeks durati on). Fecal samples were lyophilized and extracted with 80% methanol in wate r and immunoreactive 5 alpha-P-30H, 5 alpha-DHP, and P4 and (for pregnant f emales only) estrone (El) and estradiol (E2) determined by enzyme immunoass ay. Urine samples were hydrolyzed, ether-extracted, and assayed for 5a-P-30 H, Fl, and E2. HPLC cochromatography of fecal extracts with various radioac tive progestin tracers confirmed the presence of large amounts of both 5-re duced progestins (5 alpha-P-30H > 5 alpha-DHP) but not of P4. 5-Reduced pro gestins (but not P4) were excreted in a cyclic pattern and levels were sign ificantly correlated with urinary 5 alpha-P-30H. Fecal 5 alpha-P-30H showed the more pronounced and consistent luteal-phase elevation and a better cor respondence to urine with respect to timing of the luteal-phase rise. Fecal and urinary 5-reduced progestins increased gradually during early pregnanc y to maximum values around week 40-45. Levels gradually declined during the second half of pregnancy, reaching baseline values 2 days before parturiti on. Urinary estrogens did not show any cyclic pattern during the preconcept ion period and levels remained low during the first 30 weeks of gestation. Thereafter, there was a rapid 10- to 20-fold increase to maximum values at mid-pregnancy followed by a gradual decline to birth. There was no mid-preg nancy elevation in fecal estrogens, but there was a modest increase in E1 d uring the second half of gestation. (C) 1999 Academic Press.