Biomedical subjects

B C Paria

Publications and source records attributed to B C Paria.

At least 73 records · Page 4Linked to original sources

PubMed1993

Expression of the epidermal growth factor receptor gene is regulated in mouse blastocysts during delayed implantation.

The delayed implantation model was used to study epidermal growth factor receptor(s) (EGF-R) in the mouse blastocyst. Delayed implantation and blastocyst dormancy were induced by ovariectomy on day 4 of pregnancy and were maintained by daily (days 5-7) injections of progesterone (P4). Blastocyst activation and implantation were initiated by coinjection of estradiol-17 beta (E2) with P4 on the 3rd day of delay. Immunostaining of EGF-R, autoradiographic detection of 125I-labeled EGF binding, and measurement of EGF-inducible subcellular protein tyrosine phosphorylation demonstrated the loss of EGF-R from blastocysts (dormant) recovered 24 h after ovariectomy or on the 3rd day of P4-maintained delay. However, increased EGF-R levels were detected in blastocysts (activated) recovered 12 or 24 h after E2 injection. Blastocyst EGF-R mRNA levels were quantitated by reverse transcriptase (RT)-PCR and distribution of this mRNA was examined by in situ hybridization. To provide a homologous probe for these studies, a mouse EGF-R partial cDNA was cloned and used as the template for synthesis of antisense- and sense-strand EGF-R RNA. Quantitative RT-PCR demonstrated an 8- to 10-fold reduction in EGF-R mRNA copies per cell in dormant blastocysts. In contrast, an 8-fold increase in EGF-R mRNA copies per cell was detected in activated blastocysts 8 h after injection of E2. In situ hybridization detected EGF-R mRNA in most cells of normal day 4 blastocysts but not in those of dormant blastocysts. These studies establish that expression of the EGF-R gene in mouse blastocysts is tightly regulated by maternal steroid hormonal status.

Amino Acid Sequence↗

PubMed1993

Effects of 9-ene-tetrahydrocannabinol on expression of beta-type transforming growth factors, insulin-like growth factor-I and c-myc genes in the mouse uterus.

Effects of cannabinoid on expression of beta-type transforming growth factors (TGF-beta 1, -beta 2 and -beta 3), insulin-like growth factor-I (IGF-I) and c-myc genes in the uteri of adult ovariectomized mice were examined using Northern blot hybridization. Mice were exposed to 9-ene-tetrahydrocannabinol (THC) alone or in combination with an injection of estradiol-17 beta (E2) and/or progesterone (P4), and uteri were analyzed at various times thereafter. TGF-beta isoform messenger RNAs (mRNAs) persisted in ovariectomized uteri and their levels were not altered after THC treatment, whereas an injection of E2 caused a modest increase in TGF-beta 1 and -beta 3 mRNA levels at 24 h. Imposition of THC treatment advanced the stimulatory effects of E2 by changing the timing for the peak of TGF-beta 3 mRNA levels to 12 h. In comparison, E2 treatment substantially elevated the levels of TGF-beta 2 mRNA at 6 h, and THC potentiated this E2 response without affecting the timing for the response. Imposition of P4 treatment did not antagonize any of these responses. P4 treatment alone or with THC had insignificant effects on mRNA levels for these TGF-beta isoforms. Uterine levels of IGF-I and c-myc mRNAs were low in ovariectomized mice and THC did not alter these mRNA levels. In contrast, E2 treatment induced a rapid, but transient, increase in IGF-I and c-myc mRNAs, and THC antagonized the rapid c-myc mRNA response and altered the timing of the IGF-I mRNA response. P4 treatment alone also caused the transient induction of these mRNAs, but THC failed to antagonize these effects. An injection of P4 plus E2 resulted in further modest increases in IGF-I and c-myc mRNA levels as compared to E2 or P4 treatment alone. However, THC did not antagonize these transient stimulatory effects of the combined ovarian steroids. The data suggest that THC should not be classified as estrogenic or antiestrogenic. However, this compound can modulate (potentiate, antagonize and/or alter timing) the effects of ovarian steroids on uterine gene expression.

Animals↗

PubMed1992

Antisense c-myc effects on preimplantation mouse embryo development.

Antisense DNA inhibition of gene expression was explored as an approach toward elucidating mechanisms regulating development of preimplantation mammalian embryos. Specifically, a role for the c-myc protooncogene was examined. Detection of c-myc mRNA and immunoreactive nuclear c-myc protein in preimplantation mouse embryos at the eight-cell/morula and blastocyst stages suggested that this DNA-binding protein could be important during early embryo-genesis. The effects of c-myc oligodeoxyribonucleotides (oligos) on the in vitro development of two-cell mouse embryos were examined. Embryos cultured in medium containing an unmodified (phosphodiester) antisense c-myc oligo complementary to the translation initiation codon and spanning the first seven codons exhibited a dose-dependent arrest at the eight-cell/morula stage. At lower concentrations (7.5 microM) this inhibitory effect was specific to the antisense oligo and did not occur with the sense-strand complement or with duplexes of the antisense and sense oligos. However, at 4-fold higher concentrations of DNA (30 microM), all unmodified c-myc oligos were embryotoxic, causing embryos to arrest at the two-cell to four-cell stages. In contrast, almost all (98%) two-cell embryos cultured with a modified (chimeric phosphorothioate/phosphodiester) antisense c-myc oligo (7.5 microM) exhibited developmental arrest at the eight-cell/morula stage, whereas no developmental arrest occurred following incubation with high concentrations of the modified sense complement (30 microM). Culture of freshly recovered eight-cell embryos with antisense c-myc led to the absence of c-myc protein but no change in epidermal growth factor receptor in those embryos that developed a blastocoel. These effects on c-myc were specific for the antisense oligo. These results suggest that c-myc function becomes particularly critical for preimplantation mouse embryos at the eight-cell/morula stage of development and establish that antisense DNA can be successfully applied as an approach toward elucidating the roles of specific genes in preimplantation mammalian embryo development.

Animals↗

PubMed1992

Characterization of the epidermal growth factor receptor in preimplantation pig conceptuses.

Embryos recovered from sows on Days 9-13 of pregnancy (Day 0 = first day of estrus) exhibited saturable and time-dependent specific binding of 125I-epidermal growth factor (EGF). The specific binding (pg/mg protein) was greater (P less than 0.001) for Day 13 elongated conceptuses than for conceptuses of earlier stages. Scatchard analyses showed two classes of binding sites (Kd = 7.0 +/- 2.6 x 10(-11) M, Bmax = 6.2 +/- 1.4 fmol/mg protein and Kd = 3.4 +/- 0.2 x 10(-8) M, Bmax = 420 +/- 80 fmol/mg protein). The EGF receptor in Day 13 conceptus membranes is a 170-kDa protein and was phosphorylated in the presence of EGF and adenosine triphosphate. EGF stimulated protein tyrosine kinase activity about 1.6-fold over basal levels. The results show that the preimplantation pig conceptus possesses EGF-binding sites with the properties of functional EGF-receptors.

Amino Acid Sequence↗

PubMed1992

Localization and binding of transforming growth factor-beta isoforms in mouse preimplantation embryos and in delayed and activated blastocysts.

The stage and cell-specific accumulation of mammalian isoforms of transforming growth factor-beta (TGF-beta 1, TGF-beta 2, and TGF-beta 3) and TGF-beta binding were examined in the preimplantation embryo and in progesterone (P4)-treated delayed or P4 plus estradiol-17 beta (E2)-treated activated blastocysts in the mouse. Immunocytochemical studies revealed that while all three immunoreactive TGF-beta isoforms were present in one-cell embryos, very little or no immunostaining was observed in two-cell embryos. However, distinct immunostaining of these isoforms was again observed in four-cell embryos and persisted through the blastocyst stage. Among the isoforms studied, TGF-beta 2 immunostaining showed a unique pattern in late morulae. In many of these morulae, the staining was primarily observed in outside cells. However, in blastocysts, immunostaining for all three isoforms was present both in the inner cell mass (ICM) and trophectoderm (Tr). Immunostaining in sectioned blastocysts and immunosurgically isolated ICMs confirmed immunostaining in Tr and ICM cells. To ascertain whether preimplantation embryos can produce TGF-beta isoforms, immunostaining was performed in embryos grown in vitro from two-cell stage in simple balanced salt solution. Immunoreactive TGF-beta s 1-3 were present in embryos at all stages of development examined (four-cell embryos through blastocysts). The virtual absence of immunoactive TGF-beta s in two-cell embryos but their accumulation in embryos at later stages of development in vitro provides evidence that these growth factors were produced by embryos. In order to assess at what stages of development preimplantation embryos could be responsive to TGF-beta s, specific binding of [125I]TGF-beta 1 and [125I]TGF-beta 2 was performed in embryos and examined by autoradiography. Low levels of binding were first detected in eight-cell embryos. The binding increased in morulae followed by a further increase in blastocysts. Analysis of binding of [125I]TGF-beta 2 in immunosurgically isolated ICMs indicated that binding was primarily evident in Tr cells. Affinity labeling of TGF-beta 1 or TGF-beta 2 in Day 4 blastocysts revealed three classes of binding proteins with approximate molecular sizes of 65 kDa (type I), 90 kDa (type II), and greater than 250 kDa (type III), in addition to a doublet of 130 and 140 kDa proteins. This observation is similar to those reported for other cell types. The data suggest that embryos are likely to be responsive to TGF-beta s after the third cleavage.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1992

Synthesis of prostaglandins by pig blastocysts cultured in medium containing estradiol or catechol estrogen.

Two experiments were conducted to determine the effects of 2-hydroxy-estradiol-17 beta (2-OH-E2; 0, 50 and 100 microM) and estradiol-17 beta (E2; 0, 25 and 50 microM) on prostaglandin (PG) E and PGF2 alpha synthesis by day-10 pig blastocysts (day 0 is first day of estrus). Blastocysts were incubated in a modified Krebs-Ringer bicarbonate medium, supplemented with bovine serum albumin (4 mg/ml) and the vitamins and amino acids (essential and nonessential) in Minimum Essential Medium (without phenol red or antibiotics). The incubations were conducted at 39 degrees C for three 2-h periods; the second and third periods included an E2 or catechol estrogen treatment. Release of PGF2 alpha into the culture medium decreased (p less than 0.001) linearly with increasing concentrations of 2-OH-E2 in both periods. Release of PGE was not affected by 2-OH-E2, therefore 2-OH-E2 increased (p less than 0.06) the PGE:PGF2 alpha. When E2 was added to the medium, release of PGE was decreased (p less than 0.01) during the second and third periods. Release of PGF2 alpha also was decreased (p less than 0.05) by E2 during period 2, but E2 did not alter the PGE:PGF2 alpha. Content of PGs in blastocysts at recovery was less than 10% of the PGs released in vitro. Therefore, these studies demonstrate effects of both the primary and catechol forms of E2 on the synthesis of PGE and PGF2 alpha. Catechol estrogens and E2 may inhibit PG synthesis and modify the PGE:PGF2 alpha during the establishment of pregnancy in pigs.

Animals↗

PubMed1992

Effects of 9-ene-tetrahydrocannabinol on uterine estrogenicity in the mouse.

Several early (Phase I) and late (Phase II) estrogenic effects of 9-ene-tetrahydrocannabinol (THC) were examined in the adult mouse uterus. An injection of THC (2.5 or 10 mg/kg body wt) in ovariectomized mice neither stimulated uterine water imbibition or accumulation of [125I]bovine serum albumin (Phase I responses) at 6 h, nor antagonized these Phase I responses elicited by estradiol-17 beta (E2). With respect to Phase II responses, although single injections of THC (2.5, 5.0 and 10 mg/kg body wt) alone were ineffective in influencing uterine weight at 24 h or incorporation of [3H]thymidine at 18 h, this drug interfered with these responses elicited by E2 in a dose-dependent manner. In contrast, an injection of THC in progesterone (P4)-primed ovariectomized mice modestly enhanced (61%) uterine incorporation of [3H]thymidine. However, E2-stimulated uterine thymidine incorporation in P4-primed ovariectomized mice was antagonized by THC treatment. Effects of THC on blastocyst implantation were examined. Single or multiple injections of various doses of THC neither induced implantation in P4-primed delayed implanting mice, nor interfered with E2-induced implantation. Furthermore, daily injections of THC (10 mg/kg body wt) during the peri-implantation period had no apparent adverse effects on implantation, or on experimentally induced decidualization (deciduomata). The data suggest that THC is neither pro- nor antiestrogenic with respect to Phase I responses. However as regards Phase II responses, THC is modestly pro-estrogenic in the P4-treated uterus, but is anti-estrogenic in the presence of E2. These estrogen agonistic/antagonistic effects of THC on uterine Phase II responses do not adversely affect the process of implantation and decidualization.

Animals↗

PubMed1991

Metallothionein gene expression and metal regulation during preimplantation mouse embryo development (MT mRNA during early development).

In order to provide information concerning gene expression and regulation in the preimplantation mammalian embryo, and to explore the roles of metallothionein (MT) during this period of development, the constitutive and metal-induced MT mRNA levels in mouse ova, preimplantation embryos, and oviducts were determined. These results were correlated with the effects of transient exposure to high levels of metals (zinc (Zn) or cadmium (Cd] on the continued development of preimplantation embryos into blastocysts in culture. RNA from preimplantation mouse embryos at different stages of development (Days 1 through 4 of gestation; D1 = vaginal plug) was analyzed using the reverse transcriptase-polymerase chain reaction (RT-PCR) to specifically amplify MT-I and MT-II mRNA transcripts. MT-I mRNA in ova, preimplantation embryos, and oviducts was detected using in situ hybridization. This mRNA in the oviduct was also analyzed by Northern blotting. The results establish that the mouse MT genes are coordinately and constitutively expressed at low basal levels in ova and preimplantation mouse embryos. In unfertilized (ova), fertilized (one-cell) eggs, and two-cell embryos, the MT-I gene was not detectably responsive to metal ions, whereas in later cleavage stage embryos (four- and eight-cell) the MT-I gene was detectably responsive to metals in some blastomeres of some of the embryos. In contrast, after the third cleavage this gene was highly metal-inducible in essentially all cells of the embryo (morula/blastocyst). Surprisingly, the appearance of metal responsiveness of the MT genes during development correlated with decreased Zn toxicity and increased Cd toxicity; two-cell embryos were Zn-sensitive and Cd-resistant, whereas eight-cell and older embryos were Zn-resistant and Cd-sensitive. In the oviduct, MT-I mRNA was not abundant in total RNA, but was detected specifically in the epithelial cells of the isthmus region and was elevated in these cells on D3 and D4 of gestation. In the oviduct, only isthmus epithelial cells responded to metals (Zn or Cd) by increased accumulation of this mRNA. These studies suggest that preimplantation mouse embryo develops the capacity to respond to metals in the environmental milieu by induction of MT gene expression at about the third cleavage. Whether the lack of responsiveness of these genes before this stage reflects transcriptional repression or attenuated metal ion influx and/or enhanced efflux remains to be determined. Sensitivity and resistance of preimplantation embryos to acute metal toxicity involve mechanisms other than MT gene expression in preimplantation mouse embryos.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1991

Reversal of indomethacin-induced inhibition of implantation in the mouse by epidermal growth factor.

In the mouse, estriol (E3) can induce implantation as a phase I of estrogen action. E3-induced implantation was attenuated by indomethacin(INDO), an inhibitor of prostaglandin (PG) synthesis. The inhibitory effect of INDO was reversed by administration of epidermal growth factor (EGF), and this EGF effect was dose-dependent. These results suggest that one of the functions of estrogen could be to activate the EGF ligand-receptor signalling in the uterus in generating PGs required for initiation of implantation. This is consistent with the results of EGF stimulation of synthesis of PGs in uterine stromal cells in culture.

Animals↗

PubMed1991

Epidermal growth factor-specific protein tyrosine phosphorylation in preimplantation embryo development.

We examined whether epidermal growth factor (EGF)-induced preimplantation mouse embryo development and function are mediated by EGF-specific protein tyrosine phosphorylation (PTP). In situ cross-linking and autophosphorylation studies showed that EGF receptor (EGF-R) in Day 4 mouse blastocysts is a protein of approximately 170 kDa that is phosphorylated when exposed to EGF and ATP. Furthermore, EGF induced about a twofold increase in protein tyrosine kinase (PTK) activity in Day 4 blastocysts when incubated in the presence of a peptide substrate with a tyrosine moiety and ATP. RG 50864, a specific inhibitor of EGF-dependent PTK, diminished autophosphorylation of the 170-kDa protein and completely blocked PTK activity in the blastocyst induced by EGF. However, this inhibitor did not affect EGF binding to the embryonic cell surface. In contrast, an inactive tyrphostin compound, RG 50862, did not alter EGF-induced PTK activity in the blastocyst. These findings led us to examine the effects of these tyrphostin compounds on preimplantation mouse embryo development and blastocyst hatching in vitro. RG 50864, in a dose-dependent manner, inhibited EGF-dependent development of 2-cell embryos to blastocysts and the number of cells per blastocyst. This inhibitor also antagonized EGF-induced zona-hatching of blastocysts formed from 8-cell embryos in culture. However, the inhibitor was not effective in deterring transforming growth factor-beta 1-induced blastocyst formation. The inactive compound, RG 50862, had no effects on EGF-dependent blastocyst formation or zona-hatching. The data show that the effects of RG 50864 are specific and mediated by inhibition of EGF-specific PTK activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Pig endometrial cells in primary culture: morphology, secretion of prostaglandins and proteins, and effects of pregnancy.

Luminal epithelial, glandular epithelial, and stromal cells were isolated from pig endometrium by enzymatic dispersion and sieve filtration. The three cell types, maintained in primary culture, showed distinctly different morphologies when viewed by light and scanning electron microscopy. Immunocytochemical staining indicated that luminal and glandular epithelial cells were positive for both cytokeratin and vimentin. However, stromal cells were positive only for vimentin. Acid phosphatase activity was detected in the culture medium of glandular cells and increased (P less than .05) when progesterone (.1 microM) was included in the culture medium. The secretion of uteroferrin by glandular cells was also indicated by one-dimensional PAGE and Western blot analysis. Stromal cells produced more (P less than .01) prostaglandin E (PGE) than prostaglandin F2 alpha (PGF2 alpha), whereas glandular cells secreted more (P less than .01) PGF2 alpha than PGE. Pregnancy status affected prostaglandin secretion in that stromal cells secreted less (P less than .01) PGE and PGF2 alpha and glandular cells secreted less (P less than .05) PGF2 alpha when they were harvested from pregnant vs cyclic pigs. Furthermore, the PGE:PGF2 alpha ratio in medium from stromal cells was greater (P less than .01) for cells collected from pregnant pigs. This culture system provides an in vitro model for studying the hormonal regulation of the endometrium and potentially may be useful for studying interactions between endometrial cells and embryos in the pig.

Acid Phosphatase↗

PubMed1990

Catechol estrogen formation in the mouse uterus and its role in implantation.

Estradiol-2/4-hydroxylase (E-2/4-H) activity was determined in the mouse uterus during early pregnancy as well as in ovarian steroid hormone-treated ovariectomized uterus. Under the assay conditions used, E-4-H was the predominant catechol estrogen-forming monooxygenase enzyme. The inhibition of E-4-H activity by SKF-525A, metyrapone and alpha-naphthoflavone suggested involvement of cytochrome P450-dependent monooxygenases. A haloestrogen, 2-fluoroestradiol (2-FL-E2), also inhibited this activity. During the peri-implantation period, no change in uterine E-4-H activity was noted on the morning of days 2 through 5, but the activity significantly (P less than 0.01) increased in the afternoon of day 4 of pregnancy. A single injection of estradiol-17 beta (E2, 100 ng/mouse) to ovariectomized mice significantly (P less than 0.01) elevated the level of E-4-H activity at 24 h as did injections of progesterone (P4, 2 mg/mouse) for 2 days. When 2 days of P4 (2 mg/mouse) treatment was combined with a single injection of E2 (20 ng/mouse), E-4-H activity increased 1.3-fold (P less than 0.05) by 24 h above that of P4 treatment alone. Dexamethasone (200 micrograms/mouse) and cholesterol (2 mg/mouse) treatment for 2 days had no effect on E-4-H activity. Thus, the stimulatory effect of P4 and E2 on E-4-H activity appeared to be specific. The increased activity of uterine E-4-H prior to implantation on day 4 evening and the modulation of its activity by P4 and/or E2 suggest an involvement of 4-hydroxyestradiol in embryo implantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Preimplantation embryo development in vitro: cooperative interactions among embryos and role of growth factors.

We have established a model that shows cooperative interaction among preimplantation embryos and the role of growth factors on their development and growth. Two-cell mouse embryos cultured singly in 25-microliters microdrops had inferior development to blastocysts and lower cell numbers per blastocyst compared with those cultured in groups of 5 or 10. The inferior development of singly cultured embryos was markedly improved by addition of epidermal growth factor (EGF) or transforming growth factor alpha or beta 1 (TGF-alpha or TGF-beta 1) to the culture medium. The stage of embryonic development, primarily affected by these treatments, was between eight-cell/morula and blastocyst. Furthermore, blastocysts developed from eight-cell embryos cultured in groups or singly in the presence of EGF showed a higher incidence of zona hatching compared with those cultured singly in the absence of EGF. Detection of EGF receptors on the embryonic cell surface at eight-cell/morula and blastocyst stages suggests beneficial effects of EGF or TGF-alpha on preimplantation embryo development and blastocyst functions. Insulin-like growth factor I (IGF-I) had no influence on embryo development. To further document the cooperative interactions among embryos, the volume of the culture medium was doubled to 50 microliters. This increase in culture volume was even more detrimental to the development of singly cultured embryos. However, this detrimental effect was significantly reversed by EGF and reversed even more markedly by a combination of EGF and TGF-beta 1 but not by TGF-beta 1 alone. Although TGF-beta 1 plus IGF-I caused a modest improvement of embryo development, the response was not as great as shown by EGF alone. Furthermore, IGF-I had no additive effect on EGF-induced embryonic development. The study presents clear evidence that specific growth factors of embryonic and/or reproductive tract origin participate in preimplantation embryo development and blastocyst functions in an autocrine/paracrine manner.

Animals↗

PubMed1990

In vitro synthesis of prostaglandin E and F2 alpha by pig endometrium in the presence of estradiol, catechol estrogen and ascorbic acid.

These experiments were undertaken to determine the potential for estradiol-17 beta (E2), 2-hydroxyestradiol-17 beta (2-OH-E2) and 4-hydroxyestradiol-17 beta (4-OH-E2) to regulate prostaglandin (PG) E and F2 alpha synthesis by pig endometrium. Endometrium was collected from pigs on d 10 of pregnancy and incubated (15 to 20 mg/well) for three 2-h periods in 2 ml of medium in 24-well culture plates. At the end of each period, the medium was removed and frozen. Later media were thawed and assayed for PGE and PGF2 alpha. During Periods 2 and 3, the medium contained 0, 25, 50, 100 or 150 microM 2-OH-E2 (Exp. 1); 0, 25 or 50 microM 4-OH-E2 (Exp. 2); or 0, 25 or 50 microM E2 (Exp. 3). Each experiment was a factorial with 2-OH-E2, 4-OH-E2 or E2 as one main effect and 0 or 1 mM ascorbate as a second main effect. Ascorbate decreased (P less than .01) PGE and PGF2 alpha release in all experiments. Two-hydroxyestradiol-17 beta decreased (P less than .01) PGE and PGF2 alpha release into the medium during Periods 2 and 3 in a dose-dependent manner (Exp. 1). In Exp. 2, 4-OH-E2 decreased (P less than .07) endometrial release of PGE and PGF2 alpha in Periods 2 and 3 and increased (P less than .01) the PGE:PGF2 alpha in Period 3. In Exp. 3, E2 decreased release of PGE during Period 3 and PGF2 alpha release during Period 2. The PGE:PGF2 alpha was not altered by E2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Is there any delta 5-3 beta hydroxysteroid dehydrogenase activity in preimplantation embryo of rhesus monkey?

This is the first report on the histochemical assessment of delta 5-3 beta hydroxysteroid dehydrogenase activity in all the preimplantation embryonic stages in the rhesus monkey (Macaca mulatta). An apparent stage dependent increase in enzyme activity was obtained, however, distinctively a high degree of non-specificity in enzyme reaction was noted primarily in morulae and blastocysts. Such marked non-specificity in the histochemical enzyme reaction for delta 5-3 beta hydroxysteroid dehydrogenase activity was not found in mouse blastocysts. High amounts of endogenous steroids present within rhesus embryos, or the participation of non-specific dehydrogenases could account for the observed non-specificity. Furthermore, the present report documents the pattern and degree of association (r = 0.9; P less than 0.01) between developmental stage and gestational age of preimplantation rhesus embryos, and thus provides a normal in situ cell cleavage rate of preimplantation embryo in the rhesus monkey.

3-Hydroxysteroid Dehydrogenases↗

PubMed1988

Endometrial phosphatases, beta-glucuronidase and cathepsin D during menstrual cycle and pre-implantation stages of gestation in the rhesus monkey (Macaca mulatta).

beta-glucuronidase, cathepsin D, acid and alkaline phosphatases were studied in rhesus monkey endometrium during the menstrual cycle (day -6 to day +10) and pre-implantation stages (day +3 to day +6) of gestation, with day 0 considered as the day of ovulation. Acid hydrolases exhibited low levels in proliferative phase endometria followed by their gradual rise in the secretory phase of the menstrual cycle. Despite no shifts in the levels of serum progesterone and estradiol-17 beta, the pre-implantation period was, however, associated with distinct changes in enzyme profiles characterized by lower absolute levels (P less than 0.05) of acid phosphatase and beta-glucuronidase on days 3 to 6 of gestation, whereas cathepsin D activity declined significantly (P less than 0.05) on days 5 and 6. Alkaline phosphatase showed a characteristic rise during the pre-ovulatory period with a gradual lowering of its level in post-ovulatory phase endometria of a non-fertile cycle; in contrast, during early gestation, alkaline phosphatase activity showed a marked elevation (P less than 0.05) on days 5 and 6 of gestation. The significance of these findings is discussed.

Acid Phosphatase↗

PubMed1984

Role of embryonic oestrogen in rabbit blastocyst development and metabolism.

Rabbit morulae were grown for 24 h in Ham's F12 medium supplemented with BSA. CI-628 citrate (1.5 micrograms/ml), a specific oestrogen antagonist, significantly inhibited the transformation of morulae to blastocysts. This inhibition was reversed with oestradiol-17 beta (1 micrograms/ml) but not oestradiol-17 alpha (1 micrograms/ml) added to the culture medium. The specific activities of phosphofructokinase, lactic dehydrogenase, malate dehydrogenase and alkaline phosphatase in blastocysts grown in vitro for 24 h in medium TC 199 + BSA showed significant elevation with blastocyst growth and expansion, while that of acid phosphatase revealed no change, and leucine aminopeptidase activity declined significantly. These changes were markedly inhibited by CI-628 citrate (2 micrograms/ml) and were reversed by oestradiol-17 beta (0.4 micrograms/ml) but not by oestradiol-17 alpha (0.4 micrograms/ml). Our findings suggest a role of oestrogen present in the rabbit morula and blastocyst in the triggering of embryonic differentiation and metabolic functions.

Alkaline Phosphatase↗

PubMed1983

Effect of an estrogen antagonist on development of blastocysts and implantation in the hamster.

CI 628 citrate, an estrogen antagonist, was given as a single intraluminal injection (5 micrograms) on day 3 to ovariectomized, progesterone-treated hamsters. This significantly reduced embryo cleavage rate, transformation of morula into blastocyst, and completely inhibited implantation. The effects of the drug could be reversed by estradiol-17B (1 microgram) but not estradiol-17 alpha (1 microgram) injected intraluminally with CI 628 citrate. Our finding suggests a role of estrogen present in hamster preimplantation embryo in the triggering of embryonic differentiation and implantation of the blastocyst.

Animals↗