Determination of urinary estrogen by thin layer chromatography in sheep under in vivo condition of urinary chromogen reduction.

Since agreement was reached about a correlation between the output of estrogen on the one hand and placental functions and foetal viability on the other (VIDETZKY, 1965 and JAFFE and LEVITZ, 1967), numerous investigations have been published on the determination of the three classic estrogens, estrone, estradiol and estriol, in the urine of mammals. In farm animals the amount of urinary pigments (chromogens) varies seasonally according to the nature of the feed. These chromogens interfere greatly with the measurements of urinary hormones. Thus, during the course of urinary estrogen determination various chemical procedures have been developed to eliminate as far as possible these interfering substances (MILLER, 1954; VELLE, 1958; AIZAWA and PINCUS, 1964; MELLIN, ERB and ESTERGREEN, 1965; MIKLOSI and COSKER, 1967 and JONES and ERB, 1967). From the literature, it is apparent that although the published methods are extremely sensitive, they are very time consuming and require numerous steps, which lead to considerable losses in estrogen yield. In our laboratory, the urinary excretion of chromogens in the ewe could be reduced to 1.7-6.5 O/O when green fodder and dry hay were changed to exclusively dry fodder (oats), and with no effect on the level of estrogen excreted in fresh urine (CSEH, BAKSAI and OSMAN, 1970). By this means the purification process of the urine samples was simplified and more rapid, and consequently the recovery of estrogen was better.