Urinary sediments in sheep feeding on oestrogenic clover. V.* Seasonal changes in the excretion of components of calculi and sediments

Abstract

Urine collections (24-hr) were made at 14-day intervals from early July to late October on six sheep grazing a pasture with oestrogenic Trifolium subterraneum cv. Dinninup dominant.

Thin-layer chromatography was used to estimate urinary concentrations of formononetin, equol and 4'-O-methyl equol and to demonstrate the presence of benzocoumarins (urolithins A and B), biochanin A, indigotin and indirubin, which have been found in calculi or sediments from sheep grazing oestrogenic clover pastures.

Formononetin levels ranged from 0.6 to 1.0mg% until late August and then from 1.2 to 1.7 mg %, the latter level occurring in late September. Equol concentration fluctuated between 8 and 15 mg % for the first eight collections but in the last two, in early and late October, levels reached 30 and 60 mg % respectively. The concentration of 4'-O-methyl equol ranged from 3 to 8 mg % until mid August and attained a peak of 29 mg % in late August. Between early September and early October values ranged from 15 to 23 mg % but by late October only trace amounts were present.

Urolithin B appeared in all or most samples at each collection but urolithin A occurred in relatively few samples per collection until mid September. From mid September to late October the highest concentrations of both urolithins were attained. Indigotin generally occurred in only one urine at each collection but from mid August to mid September it was present in three or four urines per collection. Indirubin was present in all urines in all collections except the last, when it was present in only one urine. Biochanin A was detected only in urines collected in late September and early October.

The relevance of these results to the period of formation of different calculi or sediments found in sheep grazing oestrogenic clover pasture and the implications of the metabolism of formononetin to equol and 4'-O-methyl equol in relation to urinary tract obstruction are discussed.

________________ *Part IV, Aust. J. Agric. Res., 26: 313 (1975).