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Oestrous, luteal-phase and ovariectomized ewes were inoculated in the uterine lumen with Escherichia coli and killed 2, 4, 8 or 16 hr later. Intense leucocytic responses and closely associated bactericidal activity occurred within 4 hr in ovariectomized ewes, within 8 hr in oestrous ewes and within 16 hr in luteal-phase ewes. Intense leucocytic emigration was inhibited for 2 to 3 hr in oestrous ewes and considerably longer in luteal-phase ewes. No evidence was found that hormones inhibited the passage of extravasated leucocytes through endometrial stroma. The incubation of E. coli in excised uteri failed to indicate that non-cellular bactericidal factors were normally present in uterine lumens of ovariectomized ewes. * These data are taken from a thesis submitted by the senior author to the Graduate School, Univer¬ sity of Maryland, as part of the requirements for the degree of Master of Science.

A new micro-bio-assay method involving the increase of vaginal glycogen in response to local administration has been used to determine the oestrogenic content of urine and blood. In addition, various other steroid hormones (progesterone, cortisol, desoxycorticosterone, testosterone) were given to test the specificity of the assay. In no instance did the other hormones elicit a glycogen response when given alone, nor did they enhance the response when given in combination with oestrogen.In a previous report from this laboratory (Wrenn, Bitman & Wood, 1968), the rapid increase in vaginal glycogen caused by local administration of oestrogens to adolescent, ovariectomized rats has been characterized, and suggested as being suitable for the determination of the oestrogenic content of biological materials. The method was shown to be sensitive to small doses, with as little as 2-5 10"^g oestradiol being detected. This paper deals with the assay of biological fluids and the specificity of the reaction.The assay was conducted by instilling 0-01 ml of solution into the vaginae of 49 to 51-day-old adolescent rats which had been ovariectomized 10 to 12 days previously. The rats were killed 5 hr after the injection and the vaginae excised as described earlier (Wrenn et al., 1968). Glycogen determinations were made by the anthrone method of Seifter, Dayton, Novic & Muntwyler (1950).We have applied the assay to the determination of the oestrogenic content of a limited number of urine and blood samples. Table 1 shows the variety of materials assayed and the estimate of their potency. No activity was detected in human male and post-menopausal urines when they were instilled into the vagina in the undiluted condition. Samples of human pregnancy urine near term had the equivalent of about 2 µg oestradiol-17ß/ml of urine. It was necessary to dilute this urine 400 times with distilled water in order to get it within the limits of potency detectable by the assay. The oestrogenic potency of untreated and unconcentrated pregnant cow urine was low-only about 6°/0 of the usual urinary excretion values reported by Velie (1958). 301

The direction of uterine contractions in vivo was studied in oestrous ewes by recording the motility of exteriorized uteri on cine film. In eight control ewes, 58% of 1156 contractions moved towards the oviduct, while 16% moved towards the cervix. In eight ewes with a plastic spiral in the lumen of one horn, only 17% of 927 contractions moved towards the oviduct; 70% of the contractions moved towards the cervix. The effect of the IUD on the direction of uterine contractions may explain inhibition of sperm transport and ovum fertilization iǹ IUD' ewes.A plastic spiral placed in one uterine horn of the ewe inhibits sperm transport and ovum fertilization (Hawk, 1967). Inhibition of sperm transport is probably not due to suppression of uterine motility because the in vitro motility of strips of myometrium taken from ewes with a spiral in one uterine horn was greater than that of strips taken from control ewes (Brinsfield & Hawk, 1968). Also, attempts to overcome the antifertility effect of the spiral with various compounds which stimulate uterine contractions were unsuccessful (Warren & Hawk, 1968). The possibility remained that a spiral might inhibit sperm trans¬ port by altering some qualitative aspect of uterine motility. The present experiment was conducted to determine whether the presence of a spiral in one uterine horn would alter the direction of uterine contractions in vivo.Sixteen mature, parous ewes were checked twice daily for oestrus by the use of aproned rams. Ewes were laparotomized on Day 10 or 11 of an oestrous cycle (Day of oestrus = Day 0), a small puncture was made in the wall of one uterine horn near its anterior end and a plastic spiral measuring 32 mm in length and 10 mm in diameter was screwed in a posterior direction into the lumen through the puncture so that the spiral lay in the lengthwise centre of the horn. In eight ewes, the spiral was anchored in place by one suture through the uterine wall. The spiral was removed immediately from the remaining eight ewes; these animals served as sham-operated controls. Ewes were assigned to each group at random and the horn to be operated upon within each ewe was also selected at random.At the first oestrus of each ewe that occurred more than 2 weeks after insertion of the spiral, the ewe was anaesthetized with sodium pentobarbital and the uterus was carefully exteriorized through a mid-ventral incision. 535

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