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Search for other papers by H. SALIMI KHALIGH in
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Since the discovery that relaxin-containing preparations of the ovary of the sow inhibit uterine contractions in the non-pregnant rat, mouse and guinea-pig in vivo (Krantz, Bryant & Carr, 1950) and in vitro (Sawyer, Frieden & Martin, 1953) this property of relaxin has been tested in only a few species, and the results reported are confusing. Miller & Murray (1959), for example, failed to get inhibition of the human or rabbit uterus in vitro. In the rat, mouse and guinea-pig relaxin decreases the amplitude of contractions in the oestrogen-dominated uterus. However, in the progesterone-dominated uterus, relaxin decreases tone but has only slight and inconsistent effects on amplitude. There have been no reports of the action of relaxin on the uterus of the hamster.
In this study, forty adult female hamsters from an accredited breeder were used. Twenty-two were parous animals of which three were killed during natural oestrus and 19 were
Search for other papers by O. NILSSON in
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The effect of oestrogens on the uterus of rats and mice has been evaluated in different ways, as by observing changes in uterine weight (Astwood, 1938; Lauson, Heller, Golden & Sevringhaus, 1939), number of mitoses (Tice, 1961), nuclear volumes (Gelfant & Clemmons, 1955), or the thickness of the different tissue layers (Palkovits, Palkovits & Czeizel, 1963).
Although these methods give numerical parameters for the effect of oestrogens, they are rather elaborate, and for a rapid screening of the influence of different oestrogens or anti-oestrogens on the uterus, a more simple method would be useful.
The present paper describes a morphological test of the reaction of the mouse uterus to oestrogen which is easy to perform but permits only a subjective measurement of the effect.
The acriflavine method
An injection of oestrogen into a spayed mouse initially causes water imbibition by the uterus which can be visualized histologically, if the accumulating
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Search for other papers by A. W. ROGERS in
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SUMMARY
Previous studies have shown that under the influence of progesterone the concentrations of radioiodide in the uterus and oviduct of the rat are maintained at levels higher than that in the plasma. In the present experiments the uterus and oviducts from rats killed 2 h after the injection of Na125I were autoradiographed by a technique which permits the localization of diffusible radioactive material. In intact non-pregnant rats and ovariectomized rats not injected with progesterone, uniformly low grain densities were observed over sections of oviduct and uterus with the exception of the epithelium and lumen of the oviduct where some increase in grain density was observed. In intact and ovariectomized rats treated with progesterone and in rats killed on Day 3 or 4 of pregnancy, grain densities over the epithelium and lumen of the oviduct were very high but the fimbria of the oviduct were consistently unlabelled. The stroma underlying the oviduct epithelium was also labelled. In the uteri of these animals the principal site of concentration of radioiodide was the luminal epithelium, but for technical reasons it was not possible to exclude the stroma immediately adjacent to the luminal epithelium as a less active site of concentration of iodide. No other site in the uterus concentrated radioiodide. The luminal epithelium occupies less than 3% of the volume of the uterus in ovariectomized rats: if this tissue is taken as the sole site of iodide concentration in the uterus, the levels reached in these cells must be at least a hundred times that of the plasma when the overall uterus: plasma concentration ratio for radioiodide is 4 or more.
Search for other papers by J. C. MACARTNEY in
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Search for other papers by G. H. THOMAS in
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SUMMARY
NADP-linked 17β- and 20α-reductase has been investigated in the uterus of immature (8–15 weeks) and adult rabbits using three labelled steroid substrates: progesterone, androstenedione and oestrone. The enzymic profile of the adult uterus differed from that of the immature, in that only the adult showed high levels of a 17β-reductase which had far greater specificity for oestrone than for androstenedione. Compared with the adult rabbit, the uterus of the rat, ferret and rhesus monkey showed little or no reductase activity.
Studies on the enzyme levels of the ovariectomized adult rabbit, and the immature rabbit treated with gonadotrophin, oestradiol, and oestradiol together with progesterone, showed that the uterine oestrone 17β-reductase was stimulated by the ovarian hormones; the response of androstenedione 17β-reductase to these hormone treatments was less marked. The oestradioldependant oestrone 17β-reductase was found predominantly in the myometrium.
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Search for other papers by R. R. CHAUDHURY in
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This investigation was carried out to study the uterus-stimulating activity of the plasma of male rabbits before and after mating to see whether there was any change. Twenty experiments were performed where blood from the male rabbit was collected by means of intracardiac puncture before and 2½ min. after mating. Ice-cold polythene syringes and tubes were used for the collection of blood, and the plasma was assayed on the isolated rat uterus (Holton, 1948). The oxytocic activity was assayed against synthetic oxytocin or against a freshly prepared solution of 5-hydroxytryptamine (5-HT) in two groups of ten rabbits each. In five out of ten experiments in each group, the rat uterus in a 10 ml. bath was treated with 50 μg. dichloroisoproterenol (DCI) for 20 min. to ensure that adrenaline in the plasma would not interfere with the assay (Levy & Tozzi, 1963).
In those experiments where the plasma was assayed
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Search for other papers by G. W. Wood in
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ABSTRACT
Macrophages are constituents of all normal connective tissue including the murine uterus. Macrophages have been identified previously in endometrium and myometrium of pregnant and non-pregnant murine uterus using antibodies against macrophages. In the current study immunohistochemical analysis of murine uterus demonstrated that there were not significant quantitative differences in uterine macrophages between the dioestrous, pro-oestrous and oestrous stages. However, distributional changes occurred during the oestrous cycle. Macrophages were evenly distributed throughout uterine tissue during dioestrus, while, during pro-oestrus and oestrus, their concentration was highest in the subepithelial stroma. Because the oestrous cycle is hormonally regulated, we asked whether or not oestrogen and/or progesterone might influence macrophage distribution. Ovariectomy, which eliminates cyclical production of oestrogen and progesterone, resulted in a significant decrease in both the relative and the absolute number of uterine macrophages within 6 days. Injections of progesterone or oestrogen to ovariectomized mice resulted in restoration of uterine macrophage numbers. Injection of oestrogen plus progesterone in a regimen known to prepare the uterus for receptivity for blastocyst implantation increased the number of macrophages to levels which were consistently higher than those seen during oestrus. Moreover, following hormone administration macrophages were more concentrated in the subepithelial stroma, a distributional pattern which was most evident following injection of both hormones. The results suggest that both oestrogen and progesterone promote quantitative and distributional changes in the uterine macrophage population.
Journal of Endocrinology (1990) 126, 417–424
Search for other papers by H. Shimada in
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Search for other papers by H. Okamura in
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Search for other papers by L. L. Espey in
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Search for other papers by T. Mori in
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ABSTRACT
Plasminogen activator (PA) activity in the rat uterus was measured at fixed intervals post partum in order to determine whether this serine protease increases during the acute remodelling of tissue which occurs in the involuting uterus. Plasminogen activator activity was measured by an indirect method based on the hydrolysis of the chromogenic substrate S-2251 by PA-generated plasmin. At the time of parturition the control level of PA activity was 0·033 ± 0·018 (s.d.) μmol/4 mg uterine wet weight per 30 min. This activity increased fourfold to a peak of 0·131 ±0·036 at 3 days post partum, and then it declined steadily towards the control level during the next 7 days. Concomitantly, uterine weight decreased to 25% of the control weight by 3 days post partum, and it continued to decrease until day 15. In the 30 days post partum during which PA activity was monitored there was no significant change in plasmin inhibitors in the uterine extracts. The results suggest a correlation between PA activity and the process of tissue remodelling which occurs during involution of the rat uterus. This increase in PA might serve to activate a latent collagenase since the measured peak in PA activity happens to coincide with a reported increase in collagenolytic activity in the involuting rat uterus.
J. Endocr. (1985) 104, 295–298
Search for other papers by Z. DICKMANN in
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SUMMARY
It is shown that the uterus of the cyclic rat can be transformed into a 'delayed-implantation' uterus (i.e. a uterus in which blastocysts are maintained in a dormant condition) by ovariectomizing females and then injecting them with 2 mg. progesterone/day, for several days. Blastocysts transferred into the uteri of females so treated remained dormant for as long as the progesterone treatment was continued. Upon injecting 1 μg. oestrone together with 2 mg. progesterone, the blastocysts implanted and developed into normal foetuses.
When blastocysts were transferred on the day of ovariectomy without previous progesterone treatment, they did not survive. Apparently ovariectomy followed by progesterone injections neutralized a uterine factor detrimental to blastocysts. The number of daily progesterone injections required to neutralize this factor depended on the day of the cycle on which ovariectomy was done. Based on the latter finding, it is postulated that the endogenous oestrogen (which fluctuates during the cycle) is the factor which renders the uterus inimical to blastocysts.
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SUMMARY
Progesterone and various nor-steroids did not prevent oestrogenic interruption of early pregnancy in the mouse, although they inhibited other oestrogen-induced changes in the uterus and vagina. It is suggested that the relationship between oestrogen and progesterone is not one of simple molecular competition.
Search for other papers by R. K. JOHRI in
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Search for other papers by P. R. DASGUPTA in
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The production of hydrogen peroxide was quantitated in the uterus of cyclic, ovariectomized (treated with hormones) and pregnant (days 1–6 post coitum) rats. This phenomenon was found to be dependent on oestrogen. The uterine responsiveness to hydrogen peroxide was correlated with peroxidase-catalysed inactivation of oestrogens in this target organ.
