Uterine adrenergic and cholinesterase-positive nerves and myometrial catecholamine concentrations during pregnancy in sheep

Uterine adrenergic and cholinesterase (AChE)-positive innervation of the sheep uterus during anestrus and at 4 stages of pregnancy were examined by histochemical methods. In addition, uterine and cervical myometrium concentrations of norepinephrine (NE) and dopamine (DA) were determined using high-performance liquid chromatography. During anestrus, adrenergic and AChE-positive nerve fibers in the uterine myometrium and endometrium were primarily associated with the vasculature. Innervation of myometrial smooth muscle was almost exclusively by adrenergic fibers. In the endometrium, fibers of both types were observed closely associated with endometrial glands, and adrenergic fibers were observed in the connective tissue beneath the luminal epithelium. Density of uterine innervation decreased by day 65 of pregnancy with an additional decrease by day 105. Myometrial NE concentrations were higher in the cervix than the uterus. Uterine NE concentrations generally were not affected by pregnancy. Although cervical NE per gram of tissue decreased during pregnancy, this effect of pregnancy was not detected when NE was expressed per microgram of DNA. Myometrial DA concentrations were higher in uterine segments than in the cervix. DA concentrations decreased during pregnancy in all tissues except the posterior uterine segment. The DA to NE ratio in the uterus was greater than that for the cervix and was not generally affected by the stage of pregnancy. These results demonstrate that cholinergic and adrenergic nerves supply the sheep uterus. Decreasing fiber density during pregnancy suggests that a majority of the innervation to the sheep uterus is supplied by 'short' nerve fibers whose activity is regulated by steroids of pregnancy. The possible role of DA as a neurotransmitter in the sheep uterus is discussed.     

Regulation of pyruvate kinase and phosphoenolpyruvate carboxykinase activity in adult Fasciola hepatica (Trematoda).

F. hepatica pyruvate kinase and phosphoenolpyruvate (PEP) carboxykinase were found to have properties of regulatory enzymes in the dissimilation of PEP and the control of metabolic flow. Mn²⁺ and K⁺ were required for pyruvate kinase activity. In the presence of fructose-1, 6-diphosphate (FDP), Mg²⁺ could substitute for Mn²⁺. FDP caused a 4-fold increase in the Mn²⁺ activated pyruvate kinase activity. This was accompanied by a 12-fold decrease in apparent K_m(PEP) and a 3-fold decrease in apparent K_{m (ADP)}. ATP markedly inhibited F. hepatica pyruvate kinase, but this inhibition was relieved by FDP. Estimates of metabolic levels indicated that the pyruvate kinase is saturated with PEP and ADP in vivo, but will be highly sensitive to fluctuations in the physiological concentrations of FDP and ATP. NADH doubled the activity of the PEP carboxykinase reaction and decreased the apparent K_{m (PEP)} for this enzyme 3-fold. While the maximal activity of the PEP carboxykinase reaction was substantially higher than the pyruvate kinase reaction, the steady state concentration of PEP suggests that the PEP carboxykinase will not be saturated with this substrate.     

Endometrial and endocervical secretion: the search for histochemical differentiation

OBJECTIVE: To determine the ideal histochemical stain to differentiate between non-neoplastic and neoplastic endocervix and endometrium. STUDY DESIGN: A total of 90 cases representing nonneoplastic cervix, non-neoplastic endometrium, endocervical adenocarcinoma and endometrial adenocarcinoma were stained with toluidine blue (TB); methylene blue (MB); mucicarmine (MUC); periodic acid-Schiff before and after diastase digestion (PAS, PAS-D); Alcian blue, pH 2.5 (AB); and periodic acid-Schiff after Alcian blue, pH 2.5 (PAB). Cases were blinded and randomly divided between two pathologists for evaluation of the staining and the staining distribution of the glandular epithelium by means of a 36-color scheme. RESULTS: The majority of non-neoplastic endocervix samples stained blue with MB (57%), fuchsia with MUC (70%), magenta with PAS (77%) and PAS-D (73%) and dark turquoise with AB (70%). The majority of non-neoplastic endometrium samples stained slate blue with TB (60%) and pink with PAS-D (53.3%). There is statistical difference (p < 0.05) in the color of the epithelium and secretions between the non-neoplastic cervix and endometrium. The malignant glands of endocervical origin could be differentiated significantly (p = 0.043) from non-neoplastic endocervical epithelium by MUC. The epithelium of the non-neoplastic endometrium is significantly differentiated from malignant endometrium using TB (p = 0.015) and MB (p = 0.038). Endocervical carcinoma could be significantly differentiated from endometrial carcinoma by MB. The staining in endocervical adenocarcinoma and endometrial carcinoma was predominantly present in both apical and cytoplasmic locations compared to their non-neoplastic counterparts (endocervix, p = 0.003; endometrium, p = 0.049). CONCLUSION: This study showed that a panel of histochemical stains could differentiate glandular cells of endocervical epithelium from endometrium.     

Heteromerous interactions among glycolytic enzymes and of glycolytic enzymes with F-actin: effects of poly(ethylene glycol)

Interactions of glucose-6-phosphate isomerase (D-glucose-6-phosphate ketol-isomerase, EC 5.3.1.9), aldolase (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate lyase, EC 4.1.2.13), glyceraldehyde-3-phosphate dehydrogenase (D-glyceraldehyde-3-phosphate:NAD+ oxidoreductase (phosphorylating), EC 1.2.1.12), triose-phosphate isomerase (D-glyceraldehyde-3-phosphate ketol-isomerase, EC 5.3.1.1), phosphoglycerate mutase (D-phosphoglycerate 2,3-phosphomutase, EC 5.4.2.1), phosphoglycerate kinase (ATP:3-phospho-D-glycerate 1-phosphotransferase, EC 2.7.3), enolase (2-phospho-D-glycerate hydro-lyase, EC 4.2.1.11), pyruvate kinase (ATP:Pyruvate O2-phosphotransferase, EC 2.7.1.40) and lactate dehydrogenase [S)-lactate:NAD+ oxidoreductase, EC 1.1.1.27) with F-actin, among the glycolytic enzymes listed above, and with phosphofructokinase (ATP:D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) were studied in the presence of poly(ethylene glycol). Both purified rabbit muscle enzymes and rabbit muscle myogen, a high-speed supernatant fraction containing the glycolytic enzymes, were used to study enzyme-F-actin interactions. Following ultracentrifugation, F-actin and poly(ethylene glycol) tended to increase and KCl to decrease the pelleting of enzymes. In general, the greater part of the pelleting occurred in the presence of both F-actin and poly(ethylene glycol) and the absence of KCl. Enzymes that pelleted more in myogen preparations than as individual purified enzymes in the presence of poly(ethylene glycol) and the absence of F-actin were tested for specific enzyme-enzyme associations, several of which were observed. Such interactions support the view that the internal cell structure is composed of proteins that interact with one another to form the microtrabecular lattice.     

Electrophoretic pattern of cytosolic pyruvate kinase fractions A and B (type L and M2) from normal rat liver and Morris hepatoma 7777

Cytosolic pyruvate kinase fractions A and B obtained by salting out procedure from normal rat liver and Morris hepatoma 7777, purified by affinity chromatography on Blue Sepharose CL-6B, have shown similar electrophoretic patterns in polyacrylamide gel at pH 8.3, to previously studied pyruvate kinase extracts from chromatin of cell nuclei. Three variants (α₁, β₁, γ₁) from normal liver pyruvate kinase fraction A (type L) had the greatest electrophoretic mobility, showed sigmoidal kinetics in relation to 2-phosphoenolpyruvate (PEP), and sensitivity to ATP and fructose 1,6-diphosphate (FDP). The fraction A dominated over normal liver fraction B (type M₂), which in electrophoresis showed a slower y2 variant, similar to the fraction A of hepatoma. All variants from fractions B of normal liver and A of hepatoma had linear kinetics and were sensitive to ATP but not to FDP. The greatest differences showed pyruvate kinase fraction B from Morris hepatoma. Its all variants α₂, β₂, γ₃ were more cathodic and had linear kinetics in relation to PEP. They all were insensitive to normal signal molecules (ATP and FDP). The γ₃ alkaline variant acquired sensitivity to inhibition by l-cysteine. Showing several-fold higher activity, much greater affinity to the main substrate, and a lack of sensitivity to feed-back inhibition by ATP, it was responsible for a high rate of aerobic glycolysis and diminution of the Pasteur effect in metabolic studies. It was probably encoded during oncogene activation and plays a special role in different metabolic strategies of tumour cells.     

Light-optical and ultrastructural immunohistochemistry of antigen H-4, a common marker of epithelial cells]

Epitope localization reacting with mice monoclonal antibodies (Mabs) H 4 was investigated using the specimen of epithelium of skin, human uterine cervix as well as in the culture of epithelium cells of guinea-pig duct deferent. Mice monoclonal antibodies against antigen H 4 obtained by the hybridoma method after immunization of mice with rat colon epithelium cytoskeletal fractions were used. Mabs H 4 were shown to react with antigen of intermediate filaments of all studied normal epithelial, cancer cells as well as culture epithelial cells. Mabs H 4 are supposed to be used as a unique immunohistochemical marker of epithelium cells under normal and malignant growth conditions.     

Regulation of cyclic guanosine monophosphate-dependent protein kinase in human uterine tissues during the menstrual cycle

Contractility of uterine smooth muscle is essential for the cyclic shedding of the endometrial lining and also for expulsion of the fetus during parturition. The nitric oxide (NO)-cGMP signaling pathway is involved in smooth muscle relaxation. The downstream target of this pathway essential for decreasing cytoplasmic calcium and muscle tone is the cGMP-dependent protein kinase (PKG). The present study was undertaken to localize expression of PKG in tissues of the female reproductive tract and to test the hypothesis that uterine smooth muscle PKG levels vary with the human menstrual cycle. Immunohistochemistry was used to localize PKG in myometrium, cervix, and endometrium obtained during proliferative and secretory phases. The PKG was localized to uterine and vascular smooth muscle cells in myometrium, stromal cells in endometrium, and a small percentage of cervical stromal cells. Using Western blot analysis and protein kinase activity assays, the expression of PKG was reduced significantly in progesterone-dominated uteri compared with myometrium from postmenopausal women or women in the proliferative phase. These findings support a role for PKG in the control of uterine and vascular smooth muscle contractility during the menstrual cycle.     

Gross and histological characterization of endometrial tissues from SLA miniature pigs with cystic endometrial hyperplasia

Cystic endometrial hyperplasia (CEH) is a uterine disorder characterized by the formation of large numbers of cysts in the endometrium. The purpose of this study was to examine and characterize cell types in the endometrium associated with the cysts and uterine glands. No apparent histological differences between CEH-involved and normal uterine columnar epithelium were found. Endometrial glands in CEH-involved and normal uteri were lined with simple or ciliated columnar epithelial cells and surrounded by lamellar connective tissue. The cyst epithelium appeared to be stretched obliquely and compressed so that both the cells and nuclei were horizontally oriented relative to the cyst lumen and were surrounded by lamellar connective tissue. Electron microgaphs revealed an abnormally high number of mitochondria in the cystic cells as compared to normal glandular cells. In conclusion, CEH is characterized by the formation of cysts which develop from the uterine glandular tissue. Epithelial cells lining the glands appeared to be distorted, possibly in response to internal pressure from increased volume due to high metabolic activity, and/or no uterine luminal opening.     

Protein kinases activated by cAMP in the genital tract of spayed mice treated with oestradiol-17beta.

The cAMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37), has been studied in the vaginal epithelium, vaginal stroma, endometrium, and whole uterus of spayed mice treated with oestradiol-17 beta, and in the vaginal epithelium and uterus of spayed mice. Two protein kinase isoenzymes (PK I and PK II) were found in whole uterus, endometrium, and vaginal stroma. Vaginal epithelium contained only one isoenzyme (PK II). Oestradiol treatment increased PK I relative to PK II in the uterus. The isoenzyme pattern in the vaginal epithelium was unaltered after such treatment. The total protein kinase activity was 70% higher in uterine extracts (cytosol) than in extracts from vaginal epithelium. Oestradiol treatment did not influence the total protein kinase activity in either tissue.     

METABOLIC CONTROL MECHANISMS IN MAMMALIAN SYSTEMS

Abstract— The regulation by thyroid hormone of the activities of hexokinase (ATP: D-hexose 6-phosphotransferase; EC 2.7.1.1), phosphofructokinase (ATP: D-fructose-6- phosphate 1-phosphotransferase; EC 2.7.1.11) and pyruvate kinase (ATP: pyruvate phosphotransferase; EC 2.7.1.40) has been investigated in the soluble fractions of the cerebral cortex and cerebellum of the rat. Ontogenetic studies on these key glycolytic enzymes demonstrated marked increases in the normal cerebral cortex between 1 day and 1 yr of age; less pronounced increases in enzyme activities were noted in the normal cerebellum. Neonatal thyroidectomy, induced by treatment of 1-day-old rats with 100 μCi of ¹³¹I, ied to an impairment of body and brain growth and inhibited the developmental increases in hexokinase, phosphofructokinase and pyruvate kinase in both the cerebral cortex and cerebellum. Whereas 50 μCi of ¹³¹I had little or no effect on these brain enzymes, 200 μCi of the radioisotope markedly inhibited (35–65 per cent) the developmental increases of the various enzyme activities investigated. When administration of the radioisotope was delayed for 20 days after birth, little or no inhibition of the development of brain glycolytic enzymes was observed. Whereas treatment of normal neonatal animals with L-tri-iodothyronine had no significant effect on the activities of cerebro-cortical and cerebellar glycolytic enzymes, the hormone increased their activities in young cretinous rats. However, when the initiation of tri-iodothyronine treatment was delayed until neonatally thyroidectomized rats had reached adulthood, this hormone failed to produce any appreciable change in enzyme activity. Our results indicate that thyroid hormone exerts an important regulatory influence on the activities of hexokinase, phosphofructokinase and pyruvate kinase in the developing cerebral cortex and cerebellum.     

Comparative study of free and bound glycolytic enzymes from sea scorpion brain.

Free and bound forms of hexokinase, pyruvate kinase, and lactate dehydrogenase were prepared from the brain of the sea scorpion (Scorpaena porcus) in a low ionic strength medium. Properties of the free and bound forms were compared to determine whether binding to particulate matter could influence enzyme function or stability in vivo. Changes in pH differently affected the activity of the free and bound forms of all three enzymes. Furthermore, bound forms of hexokinase and pyruvate kinase were more stable than the free enzymes to heating at 45 degrees C. Bound hexokinase showed higher affinity for substrates (ATP, glucose) than the free form and bound lactate dehydrogenase had greater affinity for pyruvate and NADH. Although the affinities of the two forms of pyruvate kinase for substrates were similar, Hill coefficients for phosphoenolpyruvate as well as inhibition by ATP differed between the two enzyme forms. Free and bound lactate dehydrogenase also showed differences in Hill coefficients and bound lactate dehydrogenase was less sensitive to substrate inhibition by high pyruvate concentrations. The possible physiological role of the binding of these glycolytic enzymes to subcellular structures is discussed.     

Modification of the regulatory properties of pyruvate kinase of Neurospora by growth at elevated temperatures.

Pyruvate kinase (EC 2.7.1.40) was isolated from Neurospora crassa mycelium grown at 28 degrees C (PK-28) and at 42 degrees C (PK-42). The regulatory properties, particularly the response towards the allosteric effector fructose 1,6-diphosphate (FDP), was different in the two enzymes. PK-28 showed an activation by FDP but PK-42, under comparable conditions, appeared to be activated by low concentrations of FDP and inhibited by higher ones. For PK-28, complex formation with FDP results in a lowering of the isoelectric point from 6.40 to 5.50, representing the pI of the unliganded enzyme and that of the complex, respectively. In contrast to this, PK-42 exhibits a weak binding to FDP as suggested by a lack of decrease in the isoelectric point on treatment with comparable concentrations of FDP. Studies with quenching of aromatic residue fluorescence of PK-28 and PK-42, following binding of FDP, indicate that although this ligand binds to both types of enzymes the affinity for the two is vastly different. Dissociation constants of 9.3 muM and 0.1 mM were calculated for the binding of FDP to PK-28 and PK-42, respectively. It is concluded that growth at elevated temperatures induced a conformational change in the pyruvate kinase leading to partial desensitization of the allosteric site. The nature of the factor(s) responsible for this change is not understood at present.     

Increase of DNA synthesis in uterine adenomyosis in mice with ectopic pituitary isograft.

Ectopic pituitary isografts (EPI) have been found to induce a high incidence of uterine adenomyosis in SHN mice. All the SHN mice given EPI in the right uterus at 40 days of age developed uterine adenomyosis, and more than 80% of mice showed the genesis of subserosal nodules, an advanced state of adenomyosis, 65 days after EPI. Activities of both thymidylate synthetase and thymidine kinase, i.e. DNA-synthesizing enzymes in de novo and salvage pathways of pyrimidine metabolism, respectively, were significantly increased in EPI-induced uterine adenomyosis to approximately 2-fold those in normal control uteri. Bromodeoxyuridine-immunoreactive cells were regarded as the cells in S phase, and the number in the endometrial epithelium and stroma in EPI-induced uterine adenomyosis was more than 1.5-fold that in normal control uteri. EPI may affect the genesis of uterine adenomyosis generally, but not locally, because there were no differences between the right uterus with EPI and the left without EPI in the incidence of adenomyosis, histology or DNA-synthesizing enzyme activities.     

Studies of the structure--function relationships of Neurospora crassa pyruvate kinase: interaction with blue dextran--sepharose and Cibacron blue 3G-A

Blue dextran--Sepharose and Cibacron blue 3G-A interact with pyruvate kinase of Neurospora crassa. The enzyme is readily released from the substituted Sepharose column by elution with 0.17 M potassium phosphate buffer (pH 7.9), or 2 mM fructose 1,6-diphosphate (FDP), but not with either of the substrates, ADP and phosphoenolpyruvate (PEP), at 2 mM. Cibacron blue 3G A is a noncompetitive inhibitor of pyruvate kinase with respect to both substrates. It appears to compete with the allosteric effector, FDP, for binding to the enzyme surface. A lack of elution of the enzyme from the immobilized blue dextran matrix by adenine nucleotides and the absence of a difference spectrum in the 650- to 700-nm range suggest that a "dinucleotide-fold" substructure is not implicated in the dye binding sites on pyruvate kiase. The interaction of Cibacron blue 3G-A and this enzyme can be followed fluorometrically; incremental additon of the dye to the enzyme solution results in a progressive decrease in the fluorescence of surface tryptophanyl residues. The quenching of fluorescence of exposed aromatic groups is subject to reversal following addition of FDP to the pyruvte kinase--Cibacron blue complex.     

Haymaker gene expression in malignant and normal gynecologic tissues.

We previously reported that cell lines established from human carcinomas and leukemias/lymphomas expressed high levels of an intracellular membrane-bound protein, Haymaker, whereas cell lines derived from non-malignant connective tissue cells and lymphoid cells expressed low levels of this gene product. To determine whether these findings reflect neoplastic transformation or, alternatively, tissue specificity, we examined by immunohistochemical and molecular methods the expression of Haymaker in gynecologic organs with and without tumor. A highly specific, affinity-purified rabbit polyclonal antibody against a 25-mer Haymaker peptide was used for immunohistochemical staining and morphometric analysis of 85 tissue specimens. Immunohistochemical studies demonstrate, for the first time, that Haymaker protein is highly expressed in epithelial cells of the endometrium of the normal uterus and to a somewhat lesser extent in the mucosa of the normal vagina and cervix, but is poorly expressed or absent in cells of the connective tissue and smooth muscle strata of these organs (p < 0.005). Significant differences in Haymaker expression, as assessed by immunohistochemistry, between malignant and normal gynecologic tissues were not observed (p = 0.27). The expression of Haymaker protein does not appear, therefore, to be a marker of malignant transformation of the epithelium of gynecologic organs but rather distinguishes both normal and malignant epithelial cells from normal connective tissue and smooth muscle cells.     

Seasonal change and prolonged anoxia affect the kinetic properties of phosphofructokinase and pyruvate kinase in oysters

The effects of seasonal change, November versus July, and prolonged anoxia (96 h under N₂ gas) on the properties of phosphofructokinase and pyruvate kinase from five tissues (gill, mantle, hepatopancreas, phasic adductor, catch adductor) of the oyster, Crassostrea virginica, were investigated. Both enzymes showed tissue-specific and season-specific changes in kinetic properties; for pyruvate kinase this correlated with seasonal differences in enzyme elution patterns on hydroxylapatite chromatography. Kinetic properties of both enzymes in winter were consistent with primarily catabolic roles in glycolysis with responsiveness to cellular energy demands, whereas in summer these enzymes may be more closely regulated with respect to the biosynthetic and gluconeogenic functions of the tissues. Anoxia-induced changes in phosphofructokinase properties were relatively minor but anoxia stimulated changes in pyruvate kinase properties and elution profiles on hydroxylapatite in all tissues except mantle, with much greater effects seen for the enzyme from winter versus summer animals. For example, anoxia-induced changes in pyruvate kinase from winter gill included a fourfold rise in the substrate affinity constant for phosphoenolpyruvate, a sevenfold increase in the concentration of fructose-1,6-bisphosphate needed to activate the enzyme by 50%, and a 50% decrease in the concentration of L-alanine that inhibits activity by 50%. Changes in pyruvate kinase kinetics and hydroxylapatite elution patterns during prolonged anoxia are consistent with covalent modification of pyruvate kinase but contrary to results for many other mollusc species, anoxia exposure appears to induce a dephosphorylation of the enzyme. Accepted: 17 February 2000     

The abelson tyrosine kinase (c-Abl) expression on the mouse uterus and placenta during gestational period

c-Abl is a protein tyrosine kinase which has very important roles in signal transduction, control of the cell cycle, cell motility, proliferation, and inhibition of apoptosis. We hypothesized that c-Abl may play an important role on uterine remodeling during pre-receptive, receptive and non-receptive endometrium. Our aim is to investigate the expression of c-Abl protein tyrosine kinase in uterine remodeling and placental development in mouse gestational stage. We performed c-Abl immunohistochemistry on mouse uterine tissue sections on days 1–9, 11, 13, and 15 of pregnancy. c-Abl was highly upregulated in the uterine luminal epithelium and other endometrial structures including glands and blood vessels in pre-receptive and receptive endometrium. Therefore these results demonstrate a role for c-Abl in uterine remodeling during decidualization, implantation, and placentation throughout gestation.     

Synthesis of polypeptides by the cervix of the baboon (Papio anubis)

Administration of oestradiol to ovariectomized baboons caused the epithelium of the cervix to differentiate into tall columnar cells that were ciliated or secretory. Administration of progesterone in the presence or absence of oestradiol altered the appearance of the lining epithelium, suggesting a decrease in secretory activity. Fluorographs of media from cultures of tissue from steroid-treated animals reflected changes in polypeptide biosynthesis which correlated with the morphological observations: 6 polypeptides (Mr 88,000-37,000; pI 5.5-6.0) were observed in all treatment groups and, except for relative changes in intensity, these polypeptides were electrophoretically similar to those synthesized by the endometrium. A new group of low molecular weight polypeptides (Mr 23,000-20,000, pI greater than 8.0-5.5) and a basic protein (Mr 160,000) were synthesized and released in the oestradiol-dominated animal. These polypeptides were distinct to the cervical mucosa since they were not observed in the endometrium or oviduct. Progesterone suppressed the synthesis of the low molecular weight acidic polypeptides (Mr 23,000-20,000; pI 6.1-5.5) but maintained the synthesis of the basic polypeptides (Mr 23,000-20,000; pI greater than 8). Treatment with progesterone +/- oestradiol did not appear to induce the synthesis of any new major polypeptides in the cervical epithelium. These results suggest that oestradiol induces the synthesis of a group of cervix-specific polypeptides and progesterone antagonizes the action of oestradiol in the baboon cervix.     

Structural characteristics of the ceramides of neutral glycosphingolipids in the human female genital tract--their menstrual cycle-associated change in the cervical epithelium and uterine endometrium, and their dissociation in the mucosa of the fallopian tube with the menstrual cycle.

In human cervical epithelium, uterine endometrium, and mucosa of the fallopian tubes, neutral glycosphingolipids were exclusively represented by the globo-series glycosphingolipids, such as CMH, LacCer, Gb3Cer and Gb4Cer, but the molecular species of their ceramide moieties were characteristically altered in the cervical epithelium and uterine endometrium during the menstrual cycle. Individual neutral glycosphingolipids in the cervical epithelium and the uterine endometrium at the follicular phase gave two bands on TLC, whereas those at the luteal phase displayed three bands, the third being the lower migrating one. Neutral glycosphingolipids migrating to the same positions as these lower-migrating bands were constantly detected in the mucosa of the fallopian tubes, independent of the menstrual cycle. The lower-migrating bands for the cervical epithelium and the uterine endometrium at the luteal phase were due to molecules mainly constructed of phytosphingosine with alpha-hydroxy fatty acids having chain lengths of 18-24 and 4-sphingenine with alpha-hydroxy fatty acids having chain lengths of 16-22, whereas those in the mucosa of the fallopian tubes were exclusively N-alpha-hydroxypalmitoyl 4-sphingenine.     

Induction of glycolytic enzyme synthesis in proliferating fibroblasts. Study of phosphofructokinase, glucose phosphate isomerase and pyruvate kinase.

Specific activity of phosphofructokinase is 7-8-fold higher in exponentially growing human fibroblasts than in quiescent cells, but the difference is considerably less pronounced for two other glycolytic enzymes, glucose phosphate isomerase and pyruvate kinase. The ratio of the F-type to L-type phosphofructokinase subunits is essentially the same in growing and resting cells, 4:1. F-type-phosphofructokinase-related antigen concentration is decreased in resting cells as compared with proliferating fibroblasts, but relatively less than the enzyme activity; the ratio of the enzyme activity to the antigen concentration (immunological specific activity) is therefore lower in resting than in growing fibroblasts. Synthesis of phosphofructokinase, as a percentage of the total protein synthesis, is about 30-fold greater during the proliferative phase than in quiescent cells, but this difference is only 3-4-fold for glucose phosphate isomerase and pyruvate kinase. Modulation of the synthesis of phosphofructokinase therefore seems to be responsible for the changes of its specific activity in function of cell proliferation. The appearance of some inactive cross-reacting material in quiescent cells is probably due to post-translational alteration of the pre-synthesized molecules. Compared with other glycolytic enzymes, such as glucose phosphate isomerase and pyruvate kinase, phosphofructokinase seems to be the (or one of the) preferential target of glycolytic induction in proliferating cells.