Mildred E. Cerini

Effect of Progesterone on the Release of Luteinizing Hormone Induced by a Synthetic Gonadotrophin-Releasing Factor in the Ewe

A synthetic decapeptide (Gn-RH) structurally identical to ‘ovine LH-releasing hormone’ was given by intra-carotid infusions (0, 0.5 and 1.5 µ g/h for 3 h) to two groups of ewes late

Prostaglandin F2α, ‘the' Luteolysin in the Mammal?

Part. I: Prostaglandin F2Α (PGF2Α) was shown to be ‘the’ luteolysin in the ewe on the following criteria: (1) Hysterectomy and/or separation of the uterine horn from the ovary bearing a corpus luteum led to prolongation of the oestrous cycle, (2) PGF2Α shortened the cycle when administered in the midluteal phase, (3) PGF2Α was identified in uterine venous blood, (4) a mechanism for the transfer of PGF2Α from the uterine vein to the ovarian artery was shown to exist, (5) the quantitative aspects of the secretion transfer mechanism and luteolytic potency of PGF2Α were adequate to account for the observed phenomena. Part II: These criteria were applied for evaluation of PGF2Α as ‘the’ luteolysin in the following species: cattle, goat, horse, pig, guinea pig, rat, hamster, rabbit, monkey, human. On present knowledge, there appeared to be a variation between species from those in which PGF2Α was probably concerned in luteolysis and those in which the evidence was against such a role. Part III: PGF2Α was shown to be luteolytic when given by continuous infusion for 3–6 h into the lumen of the uterus in cattle as well as sheep. The minimum effective dose was of the order of 7 g/kg. The application of this finding to artificial insemination programmes was discussed.

Expression of leucocyte antigens by cells from the metrial gland of the pregnant rat

SummaryThe function of the metrial gland of the rat, and particularly of its characteristic population of granulated cells, remains unknown. However, several lines of evidence suggest that the granulated cells may derive from lymphocytes, and play a role in the immunology of pregnancy. In this study, antigen expression by granulated and other cell populations from the metrial glands of rats at Days 13 and 14 of pregnancy was studied by an indirect immunoperoxidase method. Acetone-fixed frozen sections, and cytocentrifuge preparations of collagenase-dispersed metrial gland tissue in which numbers of granulated cells had been increased by density-gradient centrifugation, were used. The primary antibodies used recognised, inter alia, B lymphocytes (MRC OX-3, MRC OX-6, MRC OX-12), T lymphocytes (MRC OX-8, W3/25, MRC OX-19), neutrophils (MRC OX-42) and cells of the monocyte/macrophage series (MRC OX-3, MRC OX-6, MRC OX-42, MRC OX43). The majority of the granulated cells, including smaller, “immature” forms, were unlabelled by any of these antibodies. Some lymphocytes, and varying numbers of larger, non-granulated cells, were labelled by OX-6, OX-12, W3/ 25, OX-42 and OX-43. In addition to lymphocytes, labelled cells included neutrophils (OX-42), endothelial cells (OX-43), and probably some macrophages (OX-6, OX-43). OX-12, which recognises the kappa chain of rat IgG, labelled some large cells which may have been stromal cells. These findings do not support the concept that the granulated cells are derived from lymphocytes.

Localization of prostaglandin F in the ovine uterus during early pregnancy

Abstract As part of a study on the anti-luteolytic action of the sheep conceptus, the distribution of prostaglandin F (PGF) within the uteri of 19 pregnant and 14 non-pregnant ewes was studied using three antisera to PGF2α and fluorescent antibody tracing. In the uteri of seven non-pregnant ewes up to Day 11 after estrus (Day 0) and in uteri of 18 19 pregnant ewes up to Day 50, PGF was localized mainly in the lamina propria, with very little on epithelial cells lining the uterine lumen. After Day 11, in the uteri of seven non-pregnant ewes, PGF was localized on the surface of luminal epithelial cells and throughout their cytoplasm, and to a lesser extent in the lamina propria. The distribution of PGF on Days 14 and 17 in the gravid and non-gravid horns of the uteri of 13 ewes made unilaterally pregnant (conceptus confined to one uterine horn) was similar to that described above for normal pregnant and non-pregnant ewes after Day 11 respectively. These results are interpreted to indicate a change in the distribution of PGF in sheep uteri due to the presence of a conceptus.

PREGNANCY ASSOCIATED ANTIGENS IN EARLY PREGNANCY IN THE EWE

Publisher Summary This chapter focuses on pregnancy-associated antigens in early pregnancy in the ewe. The establishment of pregnancy, in the first few weeks after mating, requires an immunological tolerance of the embryo by the mother and endocrine changes to facilitate implantation and the nutrient supply to the developing embryo. The chapter describes the detected presence of pregnancy-associated substances in the sheep using immunological techniques and discusses their role in early pregnancy. The activity of the rabbit antisera, as detected by immunofluorescence, can be removed either by absorption with an homogenate of uterus from ewes at day 15 of pregnancy, with an homogenate of 15–17 day old sheep embryos, or with erythrocytes from ewes between day 10 and day 15 of pregnancy. Antisera can provide a simple test for pregnancy-hemagglutination of erythrocytes indicating a positive test for pregnancy. There are several possible functions for the pregnancy-associated antigens. Even though the antigens or similar cross-reacting antigens are found in the uterus of some nonpregnant ewes, it remains possible for the pregnancy antigens to be involved in the prolongation of the life span of the corpus luteum in early pregnancy.