Faecal Metabolites of Infused ¹⁴C‐Progesterone in Domestic Livestock

Abstract

ContentsNon-invasive monitoring of the reproductive function in animals is possible by measuring steroid metabolites in the faeces. After infusion of 14C-steroids, differences between species concerning both the percentage and the delay of faecal excretion can be observed. In domestic livestock almost all faecal ''C-metabolites are found in an unconjugated form. The aim of this study was to characterize the main metabolites present in faecal samples of sheep, ponies and pigs after infusion of 14C-progesterone and to evaluate different extraction procedures. This should help to standardize and improve faecal steroid analysis. Faeces containing peak radioactivity were suspended in methanoliwater and Sep-Pak' CI8 cartridges combined with Sephadex LH-20 columns were applied to clean up the samples. Fractions were subjected to straight phase high pressure liquid chromatography (HPLC) and thin layer chromatography (TLC). Metabolites were classified by comparison with the elution patterns of steroid reference standards and by testing their immunoreactivity in different enzyme-immunoassays (EIAs). The results revealed considerable differences in the pattern of faecal progesterone metabolites between species. A great number of metabolites (mainly mono-and di-hydroxylated pregnanes a5 well as pregnanediones) was found and progesterone barely, if at all. In sheep, pregnanes containing a 20a-hydroxy (OH) group dominated (about 45%), whereas in ponies metabolites with a 20fl-OH group (about 44%; mainly one Sa-pregnanediol). and in pigs progestagens with a 20-0x0 group (4658%) predominated. Suspending the faeces with a high percentage of methanol, ethanol or iso-propanol yielded the best recoveries and enabled a practicable extraction, without an evaporation step. As a wide range of metabolites was formed, groupspecific immunoassays using antibodies with high crossreactions with pregnanes sharing a similar C-20 group should be used for measuring faecal metabolites. To verify the data of the 14C-experiments, various progesterone metabolites were measured in faecal samples of superovulated ewes. In accordance with the results of the characterized progesterone metabolites, an EIA measuring 20u-OH-pregnanes proved most suitable for non-invasive monitoring of the corpus luteum function in sheep.

Identification of Fecal Sex Steroid Metabolites and Evaluation of Ovarian Cycle and Pregnancy in Somali Wild Ass (Equus africanus somaliensis)

“…It has been reported that non-metabolized progesterone was barely present, but 5 α-pregnane-3β-ol-20-one and 5α-pregnan-3,20-dione were found in the feces of non-pregnant ponies [17]. In our study, 5 α-pregnane-3β-ol-20-one and 5α-pregnan-3,20-dione were present in the feces during pregnancy.…”

“…It has been reported that measuring fecal progestagens can be used for monitoring the estrous cycle in the domestic horse [15][16][17], Przewalski's horse [10] and Grevy's zebra [11]. In our study, the change in fecal progestagens showed ovarian cyclicity and was an average of 22.…”

Monthly Patterns of Testosterone and Behavior in Prospective Fathers

“…Assay concentration limits for reliable measurement ranged from 80 to 20% binding, which corresponded to a range of 26.7 to 939.9 pg testosterone per milliliter of saliva. The specificity of the testosterone EIA was determined by HPLC (Palme, Mö stl, Schellander, and Bamberg, 1997) and resulted in a dominating peak with the same elution pattern as testosterone.…”

Excretion rate of progesterone in milk and faeces in lactating dairy cows with two levels of milk yield

“…Results were designated as measurements of pregnanes. Several previous publications have shown that these are the principal metabolites of P4 excreted into the faeces of cattle [20,21,35,37]. Three assays were used in this study in order to measure the entire range of faecal pregnanes.…”