Search Results

You are looking at 1 - 10 of 40 items for

  • Author: L. MARTIN x
Clear All Modify Search
Free access

L. Martin

Summary. Examination by light-, transmission electron- and scanning electronmicroscopy showed that flushing the lumen of the mouse uterus with small volumes of fluid damaged the endometrium by rupturing and removing luminal epithelial cells, splitting the epithelial basement membrane and connective tissue stroma, and rupturing and leaching stromal cells and blood vessels. The damage increased with increasing progestation of the uterus and between Days 4 and 5 of pregnancy.

I conclude that many so-called 'luminal fluid' proteins originate from luminal and stromal cells, intercellular fluid and blood and that apparent changes in luminal fluid protein content during early pregnancy may largely reflect alterations in the extent and type of damage produced by flushing, as a consequence of changes in the physical state of the uterus induced by hormones and the presence of blastocysts.

Free access

L. Martin

Summary. Intrauterine instillations of oil or saline distended the uterus in ovariectomized mice treated with progesterone + oestrogen to sensitize the uterus to a decidualizing stimulus. Saline does not induce decidualization, and therefore uterine distension per se is not the trigger to decidual induction. Oil induces decidualization, but does not involve gross damage to the epithelium, penetration of oil into the stroma or release of epithelial lipid into the stroma.

Instillation (oil, saline or sham) induced a contraction of the circular muscles along the length of the uterus which closed the uterine lumen, expelled most of the oil and located the remainder primarily in the antimesometrial cleft of the lumen. Progesterone inhibited longitudinal muscle contraction and facilitated circular muscle contraction. These effects are discussed in relation to the spacing and implantation of blastocysts.

Free access

K. HUMPHREY and L. MARTIN

Summary.

Oestradiol-17β, dimethylstilboestrol (dms), MER-25 and MRL-37 given on Days 1 to 3 of pregnancy caused retention of ova in the oviduct. None of the compounds increased the numbers of overtly abnormal ova although they all increased the proportion of morulae to blastocysts found on Day 4. This apparent delay in development was not observed when ova were retained by ligation. Although it seems likely that the anti-oestrogens were effective by virtue of their oestrogenic properties they did not reduce the numbers of ova recovered, whereas oestradiol-17β did. The mechanism whereby ova are lost is not clear.

Free access

S. R. Milligan and L. Martin

Summary. The hydrostatic pressures generated during controlled flushing of the mouse uterus increased at implantation and under conditions of uterine closure. These pressures may be responsible for inducing tissue damage during flushing. The possibility that samples collected by flushing might be contaminated with interstitial fluid or plasma was studied using intravenously administered51 Cr-labelled EDTA and 125I-labelled human serum albumin as markers. The presence of both tracers was detected in all flushings and was greatest in flushings from uteri with luminal closure and early implantation sites. These observations raise serious doubts about the validity of the flushing technique for analysing uterine luminal constituents in mice.

Free access

C. A. FINN and L. MARTIN

Summary.

A single injection of 15 μg actinomycin D on Day 5 after mating interrupted pregnancy in five/five mice. To obtain information about the mode of action of the drug, its effect on the progress of the artificial decidual cell reaction was studied.

Ovariectomized mice were prepared for decidualization with exogenous hormones and decidualization induced by the intrauterine injection of arachis oil. Intraperitoneal injection of actinomycin D 7½ or 1½ hr before the decidual stimulus did not prevent the early stages of the decidual reaction but delayed by 24 to 30 hr the onset of decidual transformation of the stromal cells. It appears that the drug blocks the chain of reactions leading to decidual morphogenesis after the initiation of the reaction but that once the effect of the drug wears off, development of the decidua resumes provided the hormone conditions are adequate.

Free access

C. A. FINN and L. MARTIN

The uterus of the aged mouse does not respond to a decidual stimulus as efficiently as that of a young mouse (Finn, 1966a; Talbert & Krohn, 1966) and it is suggested that this may contribute to the decline of litter size in old mice. In young mice, closure of the uterine lumen (Potts, 1966; Finn & McLaren, 1967) and stromal cell proliferation (Finn & Martin, 1967) occur just before implantation, and are probably important in the preparation of the uterus for implantation and decidual cell formation. Both changes can be induced in ovariectomized mice; stromal proliferation by the administration of a small dose of oestrogen following several days' treatment with progesterone (Martin & Finn, 1968) ; luminal closure by progesterone alone (Martin, Finn &
Free access

C. A. FINN and L. MARTIN

In a recent paper, it was postulated that the secretion of progesterone from the ovary during early pregnancy in the mouse does not start until the 3rd day after the finding of the copulation plug (Finn & Martin, 1969). This was based on the observation that, if pregnant mice were ovariectomized a few hours after mating and given progesterone before Day 3, the mitosis which normally occurs in the uterine glands and to a lesser extent in the luminal epithelium on Day 3 (Finn & Martin, 1967) is suppressed.

The object of the present work was to see whether exogenous progesterone given to entire pregnant mice before Day 3 would cause a similar change in the pattern of uterine mitosis on Day 3

Free access

R. M. Das and L. Martin

Summary. [3H]Thymidine autoradiography was used to study cell proliferation during decidualization induced by intraluminal oil in ovariectomized mice treated with oestrogen and progesterone. Development of the decidual reaction involves two distinct populations of stromal cells. Periluminal cells start to synthesize DNA 11–15 h after instillation and by 17–20 h, without dividing, differentiate into epithelioid decidual cells which continue to incorporate [3H]thymidine, presumably becoming polyploid. Cells peripheral to this zone also start to synthesize DNA between 11 and 15 h, but at 18·5 h many have divided before differentiating. None of these dividing cells had been arrested in G2. The periluminal and peripheral cells do not appear to differ in their proliferative antecedents.

Free access

C. W. EMMENS and L. MARTIN

Summary.

U-11100A is oestrogenic in vaginal smear tests in rats and mice with a subcutaneous med of ca. 500 μg and 50 to 100 μg respectively. It is also oestrogenic orally and intravaginally and in the tetrazolium reduction test. In all tests, however, the dose-response line turns down again with higher dosage, and full responses were not obtained at the highest dose levels tested. The compound is weakly anti-oestrogenic in both vaginal smear and tetrazolium tests in mice, but exhibits complex interactions with oestradiol, the oestrogen used.

U-11100A has an antifertility action when injected on Days 1 to 3 or 4 to 6 of pregnancy in the mouse, 50 μg/day being effective on either schedule. It is felt that this is an expression of its oestrogenicity.

Free access

C. A. FINN and L. MARTIN

The control mechanisms involved in implantation can be divided into those operating from outside the uterus and intracellular controls within the organ. The hormones of the ovary ensure that uterine preparation is synchronized with the presence of a mature blastocyst in the uterine lumen, whilst the intracellular controls regulate and integrate the changes which take place within the organ and between it and the blastocyst. A prominent feature of these changes in many species is the transformation of the connective tissue stromal cells into specialized decidual cells in which the blastocyst comes to lie, either by passing through the uterine epithelium or by degeneration of the epithelium around it. This transformation will be referred to as the decidual cell reaction (DCR).

HORMONAL CONTROL

In the majority of animals implantation takes