Metabolism of oestradiol-17  and progesterone in the white rhinoceros (Ceratotherium simum simum)

Abstract

14C-Labelled oestradiol-17 beta and progesterone (50 mu Ci each) were injected i.v. into an adult female white rhinoceros and all urine and faeces collected separately over the next 4 days. The total recovery of injected label was 61%, 25% being present in the urine and 36% in the faeces. Of the radioactivity recovered, 69% was excreted on Day 2 of the collection period. Repeated extraction of samples obtained on Day 2 showed that, of the radioactivity in faeces, 92.4% was associated with unconjugated steroids whereas in the urine the proportion of conjugated and unconjugated steroids were similar (41.2% and 51.4% respectively). After phenolic separation of urinary steroids, HPLC followed by derivatization and recrystallization techniques identified progesterone as the major component of the unconjugated portion with 4-pregnen-20 alpha-ol-3-one as the principal metabolite in the conjugated fraction. Pregnanediol was not present. Oestrone appeared to be the most abundant oestrogen metabolite with smaller but significant amounts of oestradiol-17 beta and oestradiol-17 alpha in the unconjugated and conjugated fractions respectively. Small amounts of progesterone were found in the faecal extract in which the radioactivity consisted mainly of oestradiol-17 alpha and oestradiol-17 beta. The results have established the major excreted metabolites of oestradiol-17 beta and progesterone in the white rhinoceros and the development of more appropriate assay methods for monitoring ovarian function in African rhinoceroses should now be possible.

Measurement of urinary oestrogens and 20 -dihydroprogesterone during ovarian cycles of black (Diceros bicornis) and white (Ceratotherium simum) rhinoceroses

“…This observation agrees with those of Ramsay et al (1987), who used similar HPLC techniques in the black rhinoceros, and of Hindle & Hodges (1990), who demonstrated that PdG was a quantitatively unimportant metabolite of exogenously administered l4C-labelled progesterone in a female southern white rhinoceros. Attempts to monitor ovarian function by measurement of PdG in black and white rhinoceroses have reported either undetectable (Ramsay et ai, 1987) or low and variable immunoreactivity, which showed no pattern in relation to ovarian events.…”

“…Oestrogens were separated using a linear solvent gradient of 0 10% methanol in n-hexane: chloroform, 50:50 v/v, within 22 min at a flow of 2 ml/min (Hindle & Hodges, 1990). After hydrolysis and extraction, 01 ml of each solvent aliquot was injected onto the column and fractions were collected over 30 min, evaporated to dryness and reconstituted in assay buffer (1 ml).…”

“…As in most ungulates investigated (Loskutoff et al, 1983;Hodges & Green, 1989; Hodges, 1990), the Indian rhinoceros excretes pregnanediol-3a-glucuronide (PdG) as the major progesterone metabolite in the urine (Kasman et al, 1986;Hindle et ai, 1988). The most abundant urinary oestrogen is conjugated oestrone, predominantly oestrone sulphate (Kassam & Lasley, 1986;Kasman et al, 1987), and measurement of these metabolites has provided a method for monitoring the ovarian cycle and pregnancy in this species.…”

“…), Hindle & Hodges (1990) reported differences between C. simum and R. unicornis and suggested that these may account for the failure in monitoring ovarian function in African rhinoceroses. The study demonstrated that conjugated 4-pregnen-20ct-ol-3-one (20ot-dihydroprogesterone; 20a-DHP), and not PdG, is the major urinary progesterone metabolite in the white rhinoceros.…”

Avaliação da eficiência da eletroforese capilar como técnica analítica na prospecção de metabólitos de esteróides em extratos fecais de onça-pintada (Panthera onca)

“…Durante a última década, a monitoração dos metabólitos de esteróides sexuais excretado nas fezes proveu caracterização efetiva do ciclo estral, prenhez e padrões sazonais da reprodução de várias espécies de primatas, ungulados e equídeos (BAMBERG et al, 1991;HEISTERMANN et al, 1993;HINDLE, 1990;HOPPEN et al, 1992;KIRKPATRIC et al,1992;KIRKPATRICK, 1991;RISLER et al, 1987;SCHWARZENBERGER et al, 1993;SHIDELER et al, 1993;WASSER et al, 1991WASSER et al, , 1988.…”