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C R Lyttle

Publications and source records attributed to C R Lyttle.

At least 55 records · Page 3Linked to original sources
PubMed1989

Differential expression of estrogen-regulated CD4 and Ia positive cells in the immature rat uterus.

Estradiol treatment of sexually immature Sprague-Dawley, Cr:NIH-nu/+ and Cr:NIH-nu/nu rats for 2 days results in a significant increase in the number of uterine eosinophils and OX-42 positive macrophages. However, only Sprague-Dawley rats exhibit an estrogen regulated increase in the number of cells expressing immunoreactive CD4 and Ia, suggesting that the differential responsiveness to the effects of estradiol between the two strains of rats may be genetically controlled. Nevertheless, Cr:NIH-nu/nu rats, which are deficient in T-cells, possess virtually identical numbers of CD4 positive staining uterine cells as compared to their nu/+ littermate controls, indicating that the expression of immunoreactive CD4 is associated with a resident non-T-cell population. In addition, a message for rat CD4 was observed in Northern blots of uterine mRNA, suggesting that the immunoreactive CD4 expressed by uterine cells is probably a fully functional cell surface antigen/receptor rather than a truncated form which only expresses the antigenic determinant recognized by the W3/25 monoclonal antibody.

Animals↗
PubMed1989

Estradiol-stimulated increases in uterine eosinophils and nuclear type II estrogen-binding sites are prevented by pertussis toxin.

Previous studies from several laboratories have demonstrated that estradiol treatment resulted in an increase in nuclear type II binding sites. Our previous data suggest that this increase was due to the estradiol-stimulated influx of circulating eosinophils. Therefore, we suggested that the uterine nuclear type II estrogen-binding sites were not of uterine origin. In this report we present further evidence to support this hypothesis. Treatment of immature rats with estradiol resulted in the stimulation of several uterine parameters, namely wet weight, protein synthesis, eosinophil number, peroxidase activity, nuclear type II binding sites, and the synthesis and secretion of a 180-kDa protein. The coadministration of pertussigen had no effect on the estradiol-stimulated increase in wet weight, protein synthesis, or the synthesis and secretion of the 180-kDa protein. However, pertussigen did prevent the estradiol-stimulated increase in eosinophils, peroxidase activity, and nuclear type II binding sites, demonstrating a coordinated response. Since peroxidase activity is known to be contained int he eosinophil, these data are consistent with our earlier demonstration that the type II sites are of eosinophil origin. These data also support and extend our previous findings in neonatal animals that estradiol can stimulate a growth response without a corresponding increase in the nuclear type II binding sites. These results further indicate that the estradiol-stimulated increase in eosinophils does not appear to play a key role in the control of uterine growth.

Animals↗
PubMed1989

Estrogen regulation of an eosinophil chemotactic factor in the immature rat uterus.

Associated with the generalized uterine growth stimulated by estradiol in the rat are specific responses including messenger RNA (mRNA) synthesis, protein synthesis, and peroxidase activity. The increase in peroxidase activity, although sensitive to inhibitors of RNA and protein synthesis, results from an estradiol-stimulated influx of eosinophils into the uterus. We postulated the existence of an estradiol-regulated uterine chemotactic factor, testing this by an in vitro chemotactic assay with eosinophils isolated from mature rats. Treatment of immature rats with 1 microgram estradiol for 24 h resulted in a significant increase in eosinophil chemotaxis compared to uterine extracts of vehicle-treated rats. This increase was seen as early as 3 h after estradiol administration and was maximal at 24 h. The magnitude of the chemotactic response was dependent on the dose of estradiol administered (1-100 micrograms). Estrone or estriol treatment resulted in chemotactic activity greater than control but less than estradiol. Direct addition of estradiol to extracts of control animals did not increase chemotaxis. The estradiol-stimulated chemotaxis was blocked by in vivo treatment with the antiestrogen tamoxifen and by inhibitors of RNA and protein synthesis. Analysis of extracts from estradiol-treated uteri shows that the chemotactic factor is heat labile, pronase sensitive, and has a mass of approximately 20 kilodaltons (kDa). These data suggest that the estradiol-stimulated influx of eosinophils into the rat uterus is mediated by the synthesis, modification, or release of a protein whose synthesis is estradiol receptor mediated.

Animals↗
PubMed1989

Production and secretion of complement component 3 by endometriotic tissue.

Many investigators have described a variety of immune phenomena associated with endometriosis. Among these are elevated titers of activated macrophages, monokines, and lymphokines in the peritoneal fluid of patients with endometriosis. In 1980, Weed and Arquembourg first described the deposition of complement component C3 in epithelial cells of endometrial glands in patients with endometriosis. In this study our objective was to examine the synthesis and secretion of proteins by endometriotic tissue. Tissues were incubated in Minimal Essential Medium without methionine containing 50 microCi/mL [35S]methionine for 12-16 h at 37 C in 5% CO2-95% air. Twenty thousand trichloroacetic acid-precipitable counts were placed on a 7.5% sodium dodecyl sulfate-polyacrylamide gel, and the radiolabeled proteins were detected by fluorography. We examined the radiolabeled secretory proteins obtained from 17 endometriotic implants and/or endometrioma cyst walls as well as 8 control tissues. A 180 kDa protein was produced in much greater quantities by endometriotic tissue than by control tissues. In the presence of reducing agent this protein dissociated into 113- and 69-kDa subunits. To identify and quantitate this protein we performed immunoprecipitations on the incubated medium using antihuman C3 immunoglobulin G. Up to 16% of the precipitable counts were recovered with this antibody from endometriotic tissue, while a maximum of only 4.6% was recovered from control tissue. In addition, we isolated and incubated the epithelial glandular cells, stromal cells, and remaining cells from two endometriomas. The great majority of the newly synthesized and secreted C3 was found in the glandular epithelial cell incubation. Up to 60% of the total precipitable counts were recovered from the glandular cells using this antibody. Only one protein was immunoprecipitated. The immunoprecipitated protein had a mol wt of 180 kDa under nonreducing conditions and dissociated into two subunits of 113 and 69 kDa in the presence of dithiothreitol. We conclude that the glandular epithelial cells found in endometriotic implants produce and secrete complement component, C3 which could be responsible for many of the immunological phenomena now well described in endometriosis.

Adult↗
PubMed1988

Immunohistochemical characterization of the estrogen-stimulated leukocyte influx in the immature rat uterus.

Previous studies have shown that the injection of estrogen into immature rats leads to an influx of leukocytes into the uterus. Using immunoperoxidase staining and monoclonal antibodies, we have characterized the nature of the infiltrating leukocytes in frozen sections of immature rat uteri obtained following the injection of estrogen, estrogen plus pertussigen, and the antiestrogen LY117018. Estradiol treatment for 2 days resulted in a significant increase in the number of uterine eosinophils, CD4 (W3/W25)-positive helper/inducer T lymphocytes, macrophages (MRC OX-42-positive cells), and Ia (MRC OX-6)-positive cells. In contrast, estradiol treatment failed to elicit a significant increase in the number of CD8 (MRC OX-8)-positive uterine cytotoxic/suppressor T lymphocytes and/or natural killer cells, as well as MAR 18.5- and/or MRC OX-12-positive B lymphocytes. The injection of LY117018 failed to elicit any changes in the number of cells expressing any of the phenotypes under investigation. The simultaneous injection of pertussigen, the major toxin responsible for the leukocytosis- and lymphocytosis-promoting activity of Bordetella pertussis, inhibited the estrogen-induced influx of eosinophils, macrophages (MRC OX-42-positive cells), and Ia (MRC OX-6)-positive cells but failed to prevent the influx of CD4 (W3/25) positive helper/inducer T lymphocytes. These results indicate that, in the immature rat, significant differences may exist in the susceptibility of various cell populations to the effects of estrogen, particularly with regard to uterine influx following estrogen stimulation. In addition, our observations suggest that either 1) the CD4-positive cells infiltrating the uterus following estrogen treatment may use a nonpertussigen-sensitive mechanism for chemotactic factor-receptor signal transduction or 2) a subpopulation of resident uterine cells can be induced to express the CD4 antigen following estrogen and/or estrogen plus pertussigen treatment.

Animals↗
PubMed1988

Regulation of alpha 2(I), alpha 1(III), and alpha 2(V) collagen mRNAs by estradiol in the immature rat uterus.

We show that mRNAs for alpha 2(I), alpha 1(III), and alpha 2(V) collagens are regulated by estradiol in the immature rat uterus. Clones for alpha 2(I) and alpha 1(III) collagen were induced in a cDNA library prepared from estradiol-stimulated rat uterine mRNA. Alpha 2(I) collagen cDNA was identified by its characteristic hybridization pattern on Northern blots and hybridization to known probes. The sequence of alpha 1(III) collagen cDNA showed 91% amino acid sequence homology with the corresponding 525-nucleotide segment of human alpha 1(III) procollagen cDNA. Type I and type III collagen mRNAs were coordinately regulated, and showed peaks of induction at 4 and 24 hr. Three injections of estradiol, 24 hr apart, produced induction maxima 24 hr apart. The third induction, however, was suppressed relative to the first, suggesting that estrogen-stimulated factors may act to negatively regulate the uterine response to estrogen.

Amino Acid Sequence↗
PubMed1988

Cloning of estrogen-regulated messenger ribonucleic acids from rat uterus.

A cDNA library prepared from the mRNA of uteri of estrogen-stimulated immature female rats was constructed in lambda gt10. Differential screening of the hybrid phages was performed using control and stimulated cDNAs as probes. Selected clones were then characterized by Northern and Southern blot hybridizations. In all, eight unique clones corresponding to estrogen-stimulated messages in rat uterus were identified. These clones hybridized to uterine mRNAs varying in size from 1.4-8.4 kilobases. Three of the clones were characterized as coding for three different types of collagen, and one as coding for smooth muscle actin. These are described in more detail elsewhere. The kinetics of increase in estrogen-regulated messages was examined. After a single injection of estradiol, five clones, including the three collagen mRNAs, showed two peaks of accumulation, at 4 and 24 h. Messages of two other clones were maximal at 12 h. The actin clone hybridized to mRNAs with peaks at 4 h for cytoskeletal actins and 8-12 h for smooth muscle actins. Sequential 24-h injections of the hormone produced multiple peaks of mRNA accumulation with a timing consistent with the kinetics found after a single injection of hormone. The multiple injections, however, did not result in enhanced mRNA accumulation for any of these clones. In fact, several messages showed suppressed accumulation with continued estradiol administration. Accumulated inhibitory factors in uterine cells may be responsible for this refractory condition. Except for the actin mRNA, the estradiol-stimulated mRNAs were expressed mainly in uterus and ovary. These clones may be useful in studies on the mechanism of action of estrogenic hormones and their tissue-specific regulation of gene expression.

Animals↗
PubMed1987

Hormonal regulation of rat uterine secretory protein synthesis.

Treatment of the rat uterus with estradiol results in many morphological and biochemical changes. In order to examine the biochemical mechanisms of these changes, we are interested in finding a protein which can be used as an end-point indicator or marker. Estradiol administration results in the increased synthesis and release of a 115,000 and 65,000 dalton protein into the incubation media. In this paper, we demonstrate that these proteins are actually subunits of a larger protein having a molecular weight of 180,000 daltons. This protein appears to be specific to the uterus and may be produced mainly or solely by the epithelial cells. In the normal estrous cycle, maximal production is seen at estrus with essentially no production at diestrus. In the immature rat, synthesis of the 180K dalton protein is blocked by the interaction of progesterone and estradiol. However, unlike some uterine responses, the 180K protein is increased by treatment with several antiestrogens. This protein is also present in sufficient quantities to allow for the production of monoclonal antibodies. Thus this protein has many attributes of an excellent "marker protein" and will be of value in future studies aimed at elucidating the molecular mechanism(s) of steroid hormone action in the uterus.

Animals↗
PubMed1987

Uterine media proteins in the rat during gestation.

Uterine proteins secreted in response to estrogen and modulated by progesterone have previously been demonstrated in the immature rat. An in vitro radiolabeling technique with 35S-methionine was used to culture uteri from animals in estrus, pregnancy and the post partum period. Proteins released into the media (media proteins) were analyzed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. On Days 1 and 2 of pregnancy, a 115,000 M.W.--protein similar in molecular weight to one previously described by this laboratory--is prominent. Its disappearance by Day 3 coincides with increased progesterone secretion. The appearance of a 43,000 M.W. protein is the most marked change at the time of blastocyst invasion of the uterine epithelium. A new 160,000 M.W. protein begins to emerge on Day 5 and is prominent in later gestation. The latter protein is thought to be a product of the uterine decidua. Its production in ovariectomized animals is increased in the presence of progesterone and a nonspecific decidual stimulus. In the immediate post partum period, a 115,000 M.W. protein reemerges, and the 160,000 M.W. protein disappears. It is believed that these proteins are influenced by the hormonal events of pregnancy and may represent an expression of the genetic control of gestation.

Animals↗
PubMed1987

Estrogen regulation of protein synthesis in the immature rat uterus: the effects of progesterone on proteins released into the medium during in vitro incubations.

We have previously identified two major medium proteins secreted from the rat uterus during in vitro incubations that appear to be estrogen regulated. In this study, immature rats were treated with estradiol (E2) progestins, and actinomycin D. Medium proteins were analyzed after incubation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. E2 (1 microgram) increased the synthesis of proteins with mol wt of 115,000 and 65,000. Progesterone inhibited this increase when given in doses of 500 and 250 micrograms and when given within 8 h of estradiol. Lower doses of progesterone were not completely inhibitory. When actinomycin D was given within 6 h of E2, it also inhibited the E2 stimulated increase. This system may provide a useful marker for monitoring hormonal action in the luminal epithelium and may help in understanding hormonal regulation of gene expression.

Animals↗
PubMed1987

Estrogen regulation of alpha 1(I)-procollagen messenger ribonucleic acid in the rat uterus.

A cDNA library, prepared from mRNA isolated from the uteri of 3-day estradiol-stimulated immature rats, was constructed in pBR322. From this library an estrogen-regulated clone, pERU3, was isolated. This clone contained sequences complementary to uterine mRNA that migrated during gel electrophoresis as a double band of about 5.0 and 5.8 kilobases. Little of this mRNA was seen in several other tissues examined. An increase in the amount of this RNA in uterus was seen 2 h after estradiol treatment, with maximum hybridization occurring, in different experiments, between 18 and 36 h, followed by a decline. Hybridization of the cDNA insert of the pERU3 plasmid with known probes indicated that it coded for alpha 1(I)-procollagen. This conclusion was supported by in vitro translation experiments in which the hybrid-selected mRNA complementary to pERU3 DNA was shown to code for a collagenase-sensitive protein with a size corresponding to that of alpha 1(I)-procollagen. This system, therefore, provides an additional tool for the study of the estrogen regulation of gene expression in the uterus.

Animals↗
PubMed1987

Endometrial cytosolic and nuclear progesterone receptors in the luteal phase defect.

Basal body temperature profiles, serial serum progesterone levels, and serial endometrial biopsies were studied in 15 infertile women during 21 ovulatory cycles. Ten cycles (in 9 women) demonstrated luteal phase defects (LPD), diagnosed by a histological lag in endometrial maturation, normal luteal phase length, and normal luteal phase serum progesterone levels. Both normal and LPD cycles had a maximum amount of endometrial cytosolic progesterone receptor (PgR) on days 13-15, with a significant decline thereafter. LPD cycles had significantly lower endometrial nuclear PgR concentrations than did normal cycles during the proliferative phase, but luteal phase endometrial nuclear PgR levels were similar in both groups. In 2 LPD women treated with dydrogesterone, normal endometrial maturation and a decline in endometrial cytosolic PgR concentrations in the late luteal phase were found. Therefore, with the exception of endometrial nuclear PgR concentrations during the proliferative phase, we found no evidence for a major abnormality in endometrial PgR levels in LPD cycles with a lag in endometrial histology.

Adult↗
PubMed1986

Identification of uterine nuclear type II estrogen binding sites in estrogen treated rats.

Uterine nuclear fractions from estrogen-treated rats contain both the estrogen receptor and a lower affinity estrogen binding site (type II site). In Scatchard plots of estrogen binding, two types of curves are seen. The hook-shaped form is composed of a linear component (the estrogen receptor) and a convex component (the type II site) while the curvilinear form is resolvable into two linear binding species (the estrogen receptor and a secondary site). To clarify the relationship between the two forms, we examined the curvilinear form from immature rats injected for 4 days with estradiol (E2) for type II site properties. Like the hook-shaped type II, this form could be detected in a nuclear exchange assay at both 37 and 4 degrees C, but at neither temperature in the presence of reducing agent. Additionally, the steroid specificity of the curvilinear form was identical to the hook-shaped form. The hook-shaped form was found in both immature and ovariectomized adult rats implanted for 6 days with an E2-releasing Silastic capsule to provide pharmacological E2 levels. When uteri from implanted animals displaying the hook-shaped form were mixed in various ratios with uteri lacking type II sites, the curvilinear form was produced. Animals given an E2 implant for 3 days, followed by a 3 day hormone-free period showed a curvilinear form. In vivo E2 dose-response experiments showed the curvilinear form at low E2 doses and the hook-shaped form at the high dose and in implanted animals. We conclude that curvilinear Scatchard plots result from the presence of authentic type II at lower concentrations than those giving rise to the hook-shaped form.

Animals↗
PubMed1986

Estrogen regulation of protein synthesis in the immature rat uterus: the analysis of proteins released into the medium during in vitro incubation.

Immature rats were treated with estradiol (E2) or other steroids before their uteri were removed and incubated under in vitro conditions in the presence of [35S]methionine. The analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the radiolabeled proteins synthesized and released into the incubation medium demonstrate that E2 regulates the appearance of two proteins. These two proteins have mol wt of 115,000 and 65,000. The concentration of proteins in the medium increases linearly with time, suggesting that they may be secreted. These two proteins were not produced by several other tissues in response to E2 and appear to be specific to the uterus. They also appear to be increased only by estrogens (E2 greater than estrone greater than estriol) and not by other steroids tested. They are increased in response to a single injection within 6 h, and the maximal concentration of proteins occurs approximately 24 h after E2 administration. The protein concentrations have essentially returned to control values by 72 h after hormone injection. The kinetics of the induction is the same for both proteins, suggesting that their increase may be coordinated. Based on the tissue and hormone specificity of the increase in the 115,000- and the 65,000-dalton proteins, they may serve as reliable markers for the study of the uterine response to E2.

Animals↗
PubMed1986

Electrophoretic analyses of secreted human endometrial proteins: identification and characterization of luteal phase prolactin.

Endometrial protein synthesis and secretion throughout the menstrual cycle was studied by slab gel electrophoretic analysis of [35S]methionine incorporation into protein during short term culture of human endometrial tissue. A minimum of five protein bands that fluctuate during the menstrual cycle were identified on one-dimensional gels. Those with mol wt of 28K, 35K, 51K, and 59K decreased in the luteal phase, whereas a broad 25K band was induced in the luteal phase. This broad band was identified as two species of glycosylated PRL by antihuman PRL immunostaining and [3H]glucosamine incorporation.

Adult↗
PubMed1985

A possible mechanism in arterial wall for mediation of sex difference in atherosclerosis.

Female rabbits on an atherogenic diet were treated with cottonseed oil (control), tamoxifen, testosterone, or progesterone. After 10 weeks the rabbits were killed, the aortas quickly removed, graded for atherosclerosis, and incubated with [14C]proline to determine collagen and elastin synthesis. Rabbits treated with testosterone and progesterone had the greatest degree of atherosclerosis, the highest DPM in hydroxyproline of collagen and elastin, and the greatest accumulation of collagen and elastin in the aorta. Tamoxifen-treated rabbits had less incorporation of radioactivity. In separate experiments aortas of similarly treated rabbits were analyzed for estradiol and progesterone receptor density. These receptors were found to be present, and progesterone and testosterone administration caused a translocation of progesterone receptors from cytosol to nucleus. Results are consistent with the hypothesis that sex hormones can affect the development of atherosclerosis through a direct effect of the hormones on arterial wall to alter collagen and elastin synthesis, the effect being mediated through hormone receptors in the wall.

Animals↗
PubMed1985

Comparison of media proteins from ovariectomized rat uteri following estrogen treatment.

Ovariectomized rats were treated with estradiol for 3 days after which their uteri were incubated in vitro and radioactive media proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Media were also chromatographed on G-25 Sephadex Blue Sepharose columns to isolate subsets of proteins. The results demonstrate that two proteins are consistently increased following estrogen treatment. These proteins have molecular weights of 104,000 and 65,000. Neither protein binds to Blue Sepharose to a great extent. The use of the protein synthesis inhibitors, emetine and actinomycin D, demonstrates that the proteins are synthesized de novo. These two proteins may serve as markers for genomic response to estradiol in the rat uterus.

Animals↗