scholarly journals Rat uterine microbiochemistry: metabolic enzyme activities stimulated by 17-beta-estradiol are localized in epithelial cells.

1987 ◽  
Vol 35 (6) ◽  
pp. 657-662 ◽  
Author(s):  
J P Holt ◽  
E Rhe
Keyword(s):  
Enzyme Activity ◽  
Smooth Muscle ◽  
Epithelial Cells ◽  
Dose Response ◽  
Enzyme Activities ◽  
Time Course ◽  
Citrate Synthase ◽  
Ovariectomized Rats ◽  
Similar Response ◽  
Estradiol Treatment

Lactate dehydrogenase (LDH; EC 1.1.1.27), citrate synthase (CS; EC 4.1.3.7), and beta-hydroxyacyl-CoA-dehydrogenase (beta-OH-acyl-CoA-DH; EC 1.1.1.35) activities were determined in each of the three major cell types of rat uterus, i.e., epithelial, stromal, and smooth muscle, using quantitative microanalytical techniques. Adult ovariectomized rats were treated with 17-beta-estradiol to determine the time course and dose response (0.025-50 micrograms/300-g rat) effect of estrogen on enzyme activity of each type of uterine cell. The use of "oil well" and enzyme-cycling microtechniques to determine the time course and the dose responses of enzyme activity changes required microassays involving 1595 microdissected single cell specimens. Estradiol treatment increased epithelial LDH, CS and beta-OH-acyl-CoA-DH activity but had no effect on these enzymes in the stroma or in smooth muscle cells. The estradiol-stimulated peak enzyme activities on Day 4 in the intervention group are compared with those in the ovariectomized rat controls as follows: LDH, 44.5 +/- 3.5 vs 22.3 +/- 3.9; CS, 3.5 +/- 0.2 vs 1.5 +/- 0.6; beta-OH-acyl-CoA-H, 3.5 +/- 0.32 vs 2.2 +/- 0.2 (mean +/- standard deviation; mol/kg/hr). Stromal cell activities (LDH, 7.4 +/- 1.0; CS, 1.2 +/- 0.2; beta-OH-acyl-CoA-DH, 0.9 +/- 0.1) were significantly lower than epithelial cell levels and were similar to smooth muscle levels. Therefore, even in the ovariectomized animal epithelial cells have markedly higher metabolic activity compared with adjacent cells. The enzyme activities are expressed as moles of substrate reacting per kilogram of dry weight per hour. All three enzymes exhibited a 17-beta-estradiol-induced dose response between 0.025-0.15 micrograms/300-g rat. The three enzymes studied all had similar response patterns to estrogen. The effect of estradiol was restricted to epithelial cells, with enzyme activities increasing to maximal levels after approximately 96 hr of hormone treatment. This study therefore not only confirms the specific and differential metabolic responses of uterine cells to estradiol treatment, but clearly demonstrates that marked metabolic differences exist between epithelial cells and stromal or smooth muscle uterine cells.

scholarly journals Mitochondrial proliferation in the permanent vs. temporary cold: enzyme activities and mRNA levels in Antarctic and temperate zoarcid fish

2003 ◽  
Vol 285 (6) ◽  
pp. R1410-R1420 ◽  
Author(s):  
M. Lucassen ◽  
A. Schmidt ◽  
L. G. Eckerle ◽  
H.-O. Pörtner
Keyword(s):  
Enzyme Activity ◽  
Enzyme Activities ◽  
Time Course ◽  
Citrate Synthase ◽  
Expression Patterns ◽  
Thermal Adaptation ◽  
Lipid Synthesis ◽  
Mrna Levels ◽  
Transcript Levels ◽  
Cold Adapted

Adjustments in mitochondrial properties and capacities are crucial in acclimatization to seasonal cold and in evolutionary cold adaptation of marine ectotherms. Although long-term compensatory increments in aerobic capacity of fish tissues have frequently been described in response to cold, much less is known about transitional phases and gene expression patterns involved. We investigated the time course of adjustment to acute cold in liver of eurythermal eelpout Zoarces viviparus. Whereas citrate synthase (CS) activity rose progressively in liver, cytochrome c oxidase (COX) activity was not altered during cold acclimation. Species-specific RNA probes were used to determine mRNA levels. CS mRNA (nuclear encoded) displayed a delayed, transient increase in response to cold, such that transcript levels did not parallel the change in enzyme activity. The enzyme activities and mRNA levels in the confamilial Antarctic Pachycara brachycephalum indicate cold compensation of CS activity in this cold-adapted species. The ratio of CS and COX activities was elevated in acclimation and adaptation to cold, indicating enhanced citrate synthesis over respiratory chain capacities in cold-adapted liver mitochondria. This may support enhanced lipid synthesis typically found in cold. The ratio of enzyme activity and transcript levels differed largely between Z. viviparus populations from the Baltic and North Seas, indicating the influence of unidentified parameters other than temperature. Transcript levels may not be tightly correlated with enzyme activities during thermal adaptation and thereafter. The time course of the acclimation process indicates that regulation at the translational and posttranslational levels predominates in adjustment to moderate thermal challenges.

scholarly journals Stimulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in mouse uterine epithelial cells by oestradiol-17 β

1984 ◽  
Vol 218 (3) ◽  
pp. 849-855 ◽  
Author(s):  
P A Wilce ◽  
L Leijten ◽  
L Martin
Keyword(s):  
Cell Cycle ◽  
Enzyme Activity ◽  
Epithelial Cells ◽  
Time Course ◽  
Hormone Treatment ◽  
S Phase ◽  
Uterine Epithelial Cells ◽  
Coa Reductase ◽  
Two Peaks ◽  
Stimulation Of

The characteristics of 3-hydroxy-3-methylglutaryl-CoA reductase from mouse uterine epithelial cells were studied. Preliminary experiments showed that enzyme activity was stimulated approx. 10-fold 18h after administration of 100ng of oestradiol-17 beta. This activity was associated with all particulate fractions of the uterine luminal cell. The Km for D-3-hydroxy-3-methylglutaryl-CoA was 5.54 +/- 1.12 microM. The detailed time-course of oestrogen stimulation showed two peaks of activity, 9 and 15h after hormone treatment. The DNA content of the epithelial cells doubled between 6 and 12h after hormone treatment, whereas the protein content increased linearly over the 18h period. The peak of enzyme activity at 9h is associated with early S phase of the epithelial cells; the peak at 15h may be associated with a second S phase or with mitosis. Pretreatment with progesterone for 3 days before injection of oestradiol-17 beta (a treatment which inhibits uterine epithelial DNA synthesis) reduced the oestrogenic stimulation of enzyme activity by 63%; progesterone treatment alone did not stimulate enzyme activity. These data suggest that uterine epithelial 3-hydroxy-3-methylglutaryl-CoA reductase may play an important role in the cell cycle in this tissue.

scholarly journals Time course of behavioral, physiological, and morphological changes after estradiol treatment of ovariectomized rats

2011 ◽  
Vol 103 (3-4) ◽  
pp. 261-267 ◽  
Author(s):  
Nora S. Graves ◽  
Heather Hayes ◽  
Liming Fan ◽  
Kathleen S. Curtis
Keyword(s):  
Time Course ◽  
Morphological Changes ◽  
Ovariectomized Rats ◽  
Estradiol Treatment

Corticosterone 6 beta-hydroxylase in A6 epithelia: a steroid-inducible cytochrome P-450

1990 ◽  
Vol 258 (3) ◽  
pp. C480-C488 ◽  
Author(s):  
W. M. Grogan ◽  
V. M. Phillips ◽  
E. G. Schuetz ◽  
P. S. Guzelian ◽  
C. O. Watlington
Keyword(s):  
Enzyme Activity ◽  
Epithelial Cells ◽  
Rat Liver ◽  
Time Course ◽  
Effective Concentration ◽  
Enzyme Protein ◽  
Inducer Concentration ◽  
A6 Epithelia ◽  
Phenobarbital Sodium ◽  
Cytochrome P 450

We found microsomal corticosterone 6 beta-hydroxylase (6 beta-OHase) from cultured A6 kidney epithelial cells to be a cytochrome P-450 enzyme with both similarities to and differences from the rat liver steroid 6 beta-OHase P-450p. Enzyme activity was inhibited by CO, alpha-naphthoflavone, metyrapone, and clotrimazole, well-known inhibitors of P-450 enzymes, and increased by known inducers of P-450 enzymes, including dilantin, phenobarbital sodium, and corticosteroids. Moreover, some additional, relatively specific inducers of P-450p (troleandomycin and pregnenolone-16 alpha-carbonitrile) also induced the A6 6 beta-OHase, whereas inducers of other forms of P-450 (aroclor, spironolactone, and isosafrole) appeared to repress the A6 enzyme. The time course of increase in enzyme activity and increased cellular cytochrome P-450 content were consistent with increased levels of enzyme protein. Induction of 6 beta-OHase by the substrate (corticosterone), the metabolite (6 beta-OH-corticosterone), dexamethasone, and aldosterone was biphasic as a function of inducer concentration, with approximate 50% effective concentration (EC50) values of 10(-8)-10(-9) M and 10(-5)-10(-6) M for the respective components of induction. Cortisol also induced the enzyme at 10(-8)-10(-6) M; however, its metabolite 6 beta-OH-cortisol was ineffective or decreased activity at higher concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Time Course of Starch Biosynthesis Enzymes Activity and Root Tuber Starch of Four Cassava Cultivars

2017 ◽  
Vol 5 (1) ◽  
pp. 103
Author(s):  
Huifang Huang ◽  
Yanchun Luo ◽  
Qiang Huang ◽  
Yinong Tian ◽  
Huimin Li ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Enzyme Activities ◽  
Time Course ◽  
Starch Content ◽  
Growth Period ◽  
Sucrose Phosphate Synthase ◽  
Soluble Starch ◽  
Root Tuber ◽  
Related Enzyme ◽  
Total Starch

To understand the accumulation rule of cassava root tuber starch, the amylose, amylopectin and total starch content of fresh root tuber, the enzyme activities of sucrose synthase (SuS, EC 2.4.1.13) and sucrose phosphate synthase (SPS, EC 2.4.1.14) of leaves, the enzyme activities of ADP-glucose pyrophosphorylase (AGPase, EC 2.7.7.27), soluble starch synthase (SSS, EC 2.4.1.21) and starch branching enzyme (SBE, EC. 2.4.1.18) of tubers were assessed by using cultivars SC201, SC205, GR891 and GR911 leaves and root tubers during their growth period, respectively. The results as follows: the enzyme activity of leaf SPS and the synthesis direction of SuS showed the highest at August, 2010, however the enzyme activity of the decomposing direction of SuS formed parabolic curve; the enzyme activity of tuber AGPase showed an increased then decreased single peak curve, the enzyme activity of tuber SSS oscillating decreased, while the enzyme activity of SBE was relatively stable; the amylose, amylopectin and total starch contents of fresh cassava tuber were all gradually increased along with the growth period. This research would enrich our knowledge of the time course of amylose, amylopectin and total starch contents of fresh cassava tuber, and above related enzyme activities.

Calcium dependence of myosin phosphorylation and airway smooth muscle contraction and relaxation

1986 ◽  
Vol 250 (4) ◽  
pp. C597-C604 ◽  
Author(s):  
W. T. Gerthoffer
Keyword(s):  
Smooth Muscle ◽  
Steady State ◽  
Dose Response ◽  
Time Course ◽  
Physiological Salt Solution ◽  
Shortening Velocity ◽  
Myosin Phosphorylation ◽  
Calcium Dependence ◽  
Contraction And Relaxation ◽  
Isotonic Shortening

The time course and the steady-state calcium dependence of myosin phosphorylation and isotonic shortening velocity were studied during contraction and relaxation of canine tracheal smooth muscle. Dephosphorylation of myosin coincided with the decay of isotonic shortening velocity during rapid relaxation following agonist washout. However, the decay of shortening velocity preceded dephosphorylation during a slow relaxation induced by Ca2+-free physiological salt solution (PSS). Carbachol dose-response curves for isometric stress development and myosin phosphorylation were superimposable but shifted to the left of the shortening velocity dose-response. The steady-state Ca2+ dependence of myosin phosphorylation was defined using carbachol and K+ as agonists. There was a significant dissociation of dephosphorylation and relaxation following a stepwise reduction of extracellular CaCl2 concentration. This result was related to muscarinic activation because the dissociation of relaxation and dephosphorylation was reduced by atropine in muscles stimulated with K+. Myosin phosphorylation was completely dissociated from contraction when muscles were stimulated with carbachol in Ca2+-free PSS and contracted by readmission of CaCl2. Mechanisms in addition to myosin phosphorylation appear to regulate airway muscle tone and shortening velocity, and two possibilities are discussed.

scholarly journals Kinetic Behaviour of Glucose 6-Phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase in Different Tissues of Rainbow Trout (Oncorhynchus mykiss) Exposed to Non-Lethal Concentrations of Cadmium

2009 ◽  
Vol 78 (1) ◽  
pp. 179-185 ◽  
Author(s):  
Olcay Hisar ◽  
Adem Yavuz Sönmez ◽  
Şükrü Beydemir ◽  
Şükriye Aras Hisar ◽  
Telat Yanik ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Dose Response ◽  
Enzyme Activities ◽  
Response Pattern ◽  
Base Line ◽  
Phosphogluconate Dehydrogenase ◽  
Liver And Kidney ◽  
Glucose 6 Phosphate Dehydrogenase

The effects of cadmium (Cd) on the enzymatic activities of glucose 6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) were investigated in the gill, liver and kidney tissues of rainbow trout (Oncorhynchus mykiss). Three test groups of fish were subjected to increasing concentrations (1, 3 and 5 mg/l) of cadmium (Cd) in vivo, respectively. The G6PD and 6PGD activities in the gill, liver, and kidney tissues of each group of fish were measured on days 1, 3, 5 and 7. G6PD and 6PGD enzyme activities, measured in gill, liver and kidney homogenates, were stimulated by various concentrations (1, 3, and 5 mg/l) of cadmium. Although the dose-response pattern of G6PD enzyme activities in liver and kidney tissue was very similar, that in gill was different from both other tissues. The enzyme activity of G6PD enzyme was significantly stimulated after three days (Day 3) in liver and kidney tissues at a dose of 1 mg/l Cd (p < 0.05), whereas it was stimulated on the first day of experiment (Day 1) in gill, liver and kidney tissues at doses of 3 and 5 mg/l Cd (p < 0.05). However, the activity of 6PGD was stimulated after three days (Day 3) in the liver at a dose of 1 mg/l Cd (p < 0.05) and on the first day in gill, liver and kidney tissues at doses of 3 and 5 mg/l Cd (p < 0.05). The stimulation effect of the 5 mg/l dose of Cd on G6PD and 6PGD enzyme activities was significantly diminished after seven days (Day 7) in all tissues (p < 0.05). In contrast to the dose-response pattern at the dose of 5 mg/l Cd, G6PD and 6PGD enzyme activities were stimulated significantly (p < 0.05) in liver and kidney tissues at the doses of 3 and 1 mg/l Cd. The stimulation effect of cadmium on the three tissues studied was also calculated; for both of the enzymes (G6PD and 6PGD), the enzyme activity levels were stimulated by approximately 60% and 38% in gills, 68% and 44% in liver, and 67% and 41% in kidneys, respectively, over the base-line enzyme activity of the control groups during the sevenday experimental period. These findings indicate that tissue G6PD and 6PGD enzymes function to protect against cadmium toxicity.

scholarly journals Inhibition of capillary endothelial cell growth by pericytes and smooth muscle cells.

1987 ◽  
Vol 105 (3) ◽  
pp. 1455-1462 ◽  
Author(s):  
A Orlidge ◽  
P A D'Amore
Keyword(s):  
Smooth Muscle ◽  
Endothelial Cell ◽  
Epithelial Cells ◽  
Smooth Muscle Cells ◽  
Culture System ◽  
Time Course ◽  
Muscle Cells ◽  
Cell Type ◽  
3T3 Cells ◽  
The Mean

Morphological studies of developing capillaries and observations of alterations in capillaries associated with pathologic neovascularization indicate that pericytes may act as suppressors of endothelial cell (EC) growth. We have developed systems that enable us to investigate this possibility in vitro. Two models were used: a co-culture system that allowed direct contact between pericytes and ECs and a co-culture system that prevented physical contact but allowed diffusion of soluble factors. For these studies, co-cultures were established between bovine capillary ECs and the following growth-arrested cells (hereafter referred to as modulating cells): pericytes, smooth muscle cells (SMCs), fibroblasts, epithelial cells, and 3T3 cells. The modulating cell type was growth arrested by treatment with mitomycin C before co-culture with ECs. In experiments where cells were co-cultured directly, the effect of co-culture on EC growth was determined by comparing the mean number of cells in the co-cultures to the mean for each cell type (EC and modulating cell) cultured separately. Since pericytes and other modulating cells were growth arrested, any cell number change in co-cultures was due to EC growth. In the co-cultures, pericytes inhibited all EC proliferation throughout the 14-d time course; similar levels of EC inhibition were observed in SMC-EC co-cultures. Co-culture of ECs with fibroblasts, epithelial cells, and 3T3 cells significantly stimulated EC growth over the same time course (30-192% as compared to EC cultured alone). To determine if cell contact was required for inhibition, cells were co-cultured using Millicell chambers (Millipore Corp., Bedford, MA), which separated the cell types by 1-2 mm but allowed the exchange of diffusible materials. There was no inhibition of EC proliferation by pericytes or SMCs in this co-culture system. The influence of the cell ratios on observed inhibition was assessed by co-culturing the cells at EC/pericyte ratios of 1:1, 2:1, 5:1, 10:1, and 20:1. Comparable levels of EC inhibition were observed at ratios from 1:1 to 10:1. When the cells were co-cultured at a ratio of 20 ECs to 1 pericyte, inhibition of EC growth at 3 d was similar to that observed at other ratios. However, at higher ratios, the inhibition diminished so that by the end of the time course the co-cultured ECs were growing at the same rate as the controls. These results suggest that pericytes and SMCs can modulate EC growth by a mechanism that requires contact or proximity. We postulate that similar interactions may operate to modulate vascular growth in vivo.

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