LH response diminishes following increasing dosage of estradiol

Four - day cyclic female rats were ovariectomized in the morning of day 1 of diestrus and injected on this and the following two days at 09.00 h either with constant or with increasing doses of estradiol benzoate [EB]. The serum concentrations of LH and estradiol - 17 beta were determined 4 h after the last injection. Significant inhibition of LH secretion resulting from three injections of 0. 25 micro g EB/100g b. w. was completely prevented when 0.75 micro g EB/100g b. w. were administered at increasing dosage. Markedly higher serum concentrations of estradiol were found after the administration of 0.05, 0.10 and 0.25 than after three injections of 0.13 micro micro g EB/100 g b. w; but the circulating LH level did not differ between both groups. Even the total amount of 4.0 micro g EB/100 g b. w. did not inhibit LH secretion when increasing dosage was applied. Although preliminary, the data indicate a hitherto unknown action of estrogens in the control of LH secretion which may be of importance for the therapeutic use of these hormones

Effect of estrogens on the adhesion of trichomonas vaginalis to epithelial cells in vitro

The feeding behavior of six triatomid species toward latex condoms filled with blood at 26 ñ 1 and 36 ñ 1 grade C observed for 4 h. The species studied were Triatoma infestans, Triatoma brasiliensis, Tritoma vitiiticeps, Triatoma pseudomaculata, Rhodnius and Panstrongylus, and 34 to 348 insects were studied in each group (average, 190). All the life stages of each species were used. Although most insects (80%, average for 6 species) preferred the warmer blood, 54% of the individuals of all species fed on blood kept at 26 grade C. For Triatoma pseudomaculata, a higher proportion of insects fed on blood at 26 grade C (92%) than on blood at 36 grade C (65%). These results suggest that bait containing insecticides which are effective through the digest tract may be useful in the control of these vectors even at room temperature