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UBC Theses and Dissertations

The estrogen-like substances in various legumes and grasses, and the effect of these compounds on the reproduction and growth of certain laboratory animals Swierstra, Ernest Emke

Abstract

A three day mouse bio-assay procedure, using immature female mice 20-21 days old and weighing 8-11 gm., was developed for the determination of the estrogen-like substances in forages. With diethylstilbestrol (D.E.S.) as reference compound a dose response curve was constructed. From this curve the estrogenic activity of the samples of plant material was estimated and expressed in terms of D.E.S. An extensive study was undertaken on the effects of stage of maturity and frequency of cutting of alfalfa, white clover, red clover, birdsfoot trefoil and orchard grass, on the levels of estrogen-like substances in these plant species. The data of these experiments revealed that there was a great difference in estrogenic activity between samples taken from different plant species at the same time of the year. There also was a seasonal variation between first cuttings of second year growth of the different plant species. Alfalfa and white clover were high in estrogenic activity in the spring, showed a sharp decrease in June and July, and after August 1 possessed once again considerable potency. Birdsfoot trefoil and orchard grass showed estrogenic activity only in the spring, and this was, relatively small as compared to the activity of alfalfa, white clover and red clover. Red clover differed very much from the previously mentioned species. All samples studied showed considerable potency. There was no sharp decrease during June and July as was the case with alfalfa and white clover. Data obtained by varying the number of hours of daylight (photoperiod) received by red clover seemed to indicate that estrogenic potency was decreased when the hours of daylight were reduced. Proximate analysis of the plant material revealed that estrogenic potency was not correlated with nitrogen content. Studies on the stability of the estrogen-like compound in alfalfa, white clover and red clover showed that the activity of dried ground alfalfa and white clover plant material was easily destroyed during storage, while the potency of dried ground red clover remained fairly constant over a six month period. However, the estrogen-like compounds of these three species are much more stable after they had been extracted and the extract mixed with feed. Red clover and birdsfoot trefoil extract interfered with the reproduction in the mouse. Females were affected more severely than males, but both recovered their reproductive ability quickly after feeding of the estrogen-like compounds ceased. The growth rate of the female guinea pig weighing between 500-600 gm. was not significantly influenced when red clover extract was added to their diet. II . ABSTRACT A three day mouse bio-assay procedure, using immature female mice 20-21 days old and weighing 8-11 gm., was developed for the determination of the estrogen-like substances in forages. With diethylstilbestrol (D.E.S.) as reference compound a dose response curve was constructed. From this curve the estrogenic activity of the samples of plant material was estimated and expressed in terms of D.E.S. An extensive study was undertaken on the effects of stage of maturity and frequency of cutting of alfalfa, white clover, red clover, birdsfoot trefoil and orchard grass, on the levels of estrogen-like substances in these plant species. The data of these experiments revealed that there was a great difference in estrogenic activity between samples taken from different plant species at the same time of the year. There also was a seasonal variation between first cuttings of second year growth of the different plant species. Alfalfa and white clover were high in estrogenic activity in the spring, showed a sharp decrease in June and July, and after August 1 possessed once again considerable potency. Birdsfoot trefoil and orchard grass showed estrogenic activity only in the spring, and this was relatively small as compared to the activity of alfalfa, white clover and red clover. Red clover differed very much from the previously mentioned species. All samples studied showed considerable potency. There was no sharp decrease during June and July as was the case with alfalfa and white clover. Data obtained by varying the number of hours of daylight (photoperiod) received by red clover seemed to indicate that estrogenic potency was decreased when the hours of daylight were reduced. Proximate analysis of the plant material revealed that estrogenic potency was not correlated with nitrogen content. Studies on the stability of the estrogen-like compound in alfalfa, white clover and red clover showed that the activity of dried ground alfalfa and white clover plant material was easily destroyed during storage, while the potency of dried ground red clover remained fairly constant over a six month period. However, the estrogen-like compounds of these three species are much more stable after they had been extracted and the extract mixed with feed. Red clover and birdsfoot trefoil extract interfered with the reproduction in the mouse. Females were affected more severely than males, but both recovered their reproductive ability quickly after feeding of the estrogen-like compounds ceased. The growth rate of the female guinea pig weighing between 500-600 gm. was not significantly influenced when red clover extract was added to their diet.

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