Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Explants of mammary tissue from pseudopregnant rabbits were cultured at 37 degrees C in air for 24-48h in Medium 199 buffered with 20mm-Hepes [4-(2-hydroxyethyl)-1-piperazine-ethanesulphonic acid]. The medium contained insulin and corticosterone, or insulin, corticosterone and sheep prolactin in the presence or absence of ouabain, an inhibitor of Na(+)/K(+)-dependent adenosine triphosphatase. The responses of explants were assessed histologically, by measuring the tissue concentration of K(+), and by rates of synthesis of RNA, protein and fatty acids. The effect of ouabain on Na(+) and K(+) concentrations in slices of lactating rabbit mammary-gland tissue incubated for 1h at 37 degrees C in Krebs bicarbonate buffer was also studied. 2. Prolactin increased the concentration of K(+) in mammary explants, an effect prevented by ouabain. In slices of lactating tissue, there was a linear relationship between the log dose of ouabain (from 0.1 to 10mum) and increased Na(+) and decreased K(+) concentrations in the tissue. 3. Ouabain at concentrations up to 1mum did not affect the rate of synthesis of RNA, protein or fatty acids by explants cultured with insulin and corticosterone. By contrast, the stimulatory effect of prolactin on protein synthesis was diminished and the induction of medium-chain fatty acid synthesis by prolactin was almost abolished. RNA synthesis was unaffected. Histological examination showed no tissue damage by 1mum-ouabain. 4. Explants cultured in the presence of 2mum-ouabain for 24h retained their ability to respond to prolactin when the ouabain was removed from the culture medium. Between 24 and 48h they showed responses to prolactin of a magnitude similar to those of explants never exposed to ouabain. 5. These results show that a fully functional Na(+)/K(+)-dependent adenosine triphosphatase system is necessary for prolactin to promote secretory activity in rabbit mammary gland.
...
PMID:Inhibition by low concentrations of ouabain of prolactin-induced lactogenesis in rabbit mammary-gland explants. 56 78

Ovariectomized guinea-pigs were given a single dose of oestrogen or progestogen or the two steroids combined. Controls were given 0.9% saline. Four days after the injection, myometrial contractility in response to spasmogens was measured isometrically in isolated tissue baths, both before and after incubation in Kreb's solution with or without added prolactin. Further myometrial strips were also incubated with or without prolactin and the density of Na+/K+ ATPase 'pump' sites on the surface of the myometrial cell was estimated by labelling with tritiated ouabain. Incubation with prolactin significantly reduced the contractility of myometrial tissue from guinea-pigs given saline alone, progestogen alone or progestogen plus oestrogen, but not in tissue from animals pretreated with oestrogen. When myometrial strips from animals pretreated with oestrogen or progestogen were incubated without prolactin in the medium, there was a significant increase in the density of pump sites compared with the number in saline-pretreated animals; incubation with prolactin did not further modify this effect. When both steroids were administered together there was a significant increase only when prolactin was present in the incubation medium. There was also a significant increase in the density of pump sites after incubation of myometrium from the control (saline-pretreated) animals in the presence of prolactin.
...
PMID:Effects of ovarian steroids and prolactin on the contractility and sodium pump site density of guinea-pig myometrium. 64 36

The effect of prolactin (PRL) on renal Na+K(+)-ATPase was investigated in 7-d-old neonatal rats. Animals were treated by bromocriptine (Br; a blocker of endogenous PRL secretion), and the enzyme activity was compared with that of untreated controls. Na+K(+)-ATPase was determined in renal sections in the medullary thick ascending limb of Henle's loop and in the distal tubule by cytochemistry. In the distal tubule, Na+K(+)-ATPase activity was significantly lower in Br-treated animals than in controls (330 +/- 169 versus 558 +/- 146 pmol inorganic phosphate/mm/h, respectively); values did not differ in the medullary thick ascending limb of Henle's loop between Br-treated and control animals (132 +/- 74 versus 165 +/- 113 pmol inorganic phosphate/mm/h, respectively). In vitro effects of PRL were investigated by determining the enzyme activity after incubation of renal sections from Br-treated and untreated animals with different concentrations of PRL. Results suggest that PRL may affect renal Na+K(+)-ATPase activity in the distal tubule in the neonatal period but do not support a major role of PRL in the enzyme maturation.
...
PMID:Effects of prolactin on Na+K(+)-ATPase activity in the nephron during maturation in the rat. 131 58

1. The involvement of gill (Na+ +K+)-ATPase in salmonid adaptation to salt water (SW) is discussed. 2. Gill (Na+ +K+)-ATPase increase during SW adaptation is mainly related to the increased number and complexity of chloride cells deputed to salt extrusion. 3. The temporal relationships between serum peaks of thyroid hormones, cortisol, growth hormone, prolactin and gill (Na+ +K+)-ATPase rise during salmonid smoltification, suggest a hormonal involvement in the enzyme stimulation and thus in the acquirement of SW tolerance. 4. Literature on gill (Na+ +K+)-ATPase response to hormonal treatment is reviewed. The effects produced on gill (Na+ +K+)-ATPase and chloride cells by exogenous hormones point out a complex inter-relationship between the hormones considered. The mechanisms involved in hormonal regulation of the enzyme remain a matter of debate.
...
PMID:Gill (Na+ +K+)-ATPase involvement and regulation during salmonid adaptation to salt water. 135 28

Using medium with a low ionic strength, a low concentration of Ca2+ and Mg2+ and devoid of K+, we have measured Ca(2+)-ATPase activity in the homogenates of rat islets preincubated for 3 min with several hormones in the presence of 3.3 mmol glucose/l. Insulin secretion was also measured in islets incubated for 5 min under identical experimental conditions. Islets preincubated with glucose (3.3 mmol/l) and glucagon (1.4 mumol/l) plus theophylline (10 mmol/l), ACTH (0.11 nmol/l), bovine GH (0.46 mumol/l), prolactin (0.2 mumol/l) or tri-iodothyronine (1.0 nmol/l) have significantly lower Ca(2+)-ATPase activity than those preincubated with only 3.3 mmol glucose/l. All these hormones increased the release of insulin significantly. Dexamethasone (0.1 mumol/l) and somatostatin (1.2 mumol/l) enhanced the Ca(2+)-ATPase activity while adrenaline (10 mumol/l) did not produce any significant effect on the activity of the enzyme. These hormones decreased the release of insulin significantly. These results demonstrated that islet Ca(2+)-ATPase activity was modulated by the hormones tested. Their inhibitory or enhancing effect seemed to be related to their effect on insulin secretion; i.e. those which stimulated the secretion of insulin inhibited the activity of the enzyme and vice versa. Hence, their effect on insulin secretion may be due, in part, to their effect on enzyme activity and consequently on the concentration of cytosolic Ca2+. These results reinforce the assumption that Ca(2+)-ATPase activity participates in the physiological regulation of insulin secretion, being one of the cellular targets for several agents which affect this process.
...
PMID:Correlation between Ca(2+)-ATPase activity of rat islet cells and insulin secretion. 135 67

Effects of prolactin on morphology and numbers of chloride cells in the opercular membrane of seawater-adapted tilapia (Oreochromis mossambicus) have been examined. Following five daily injections of ovine prolactin at a dose of 10 micrograms.g body wt-1, blood samples were taken and opercular membranes were removed and stained with a fluorescent mitochondrial dye (dimethylaminostyrylethylpyridiniumiodine), a fluorescent derivative of ouabain (anthroylouabain), and a histological stain specific for the extensive tubular system of chloride cells (zinc-osmium-iodine). Mean plasma osmolarity and sodium increased 23-24% following prolactin injection. An increase in the relative frequency of chloride cells between 20 and 180 microns2 in cross-sectional area and a decrease in the relative frequency of chloride cells greater than 180 microns2 were observed following prolactin injections. Average cell size decreased 46-70% and cell height decreased 26-38% following prolactin injections. There was no significant change in cell density. Anthroylouabain staining was observed in both prolactin- and saline-injected fish, and no significant effect on Na+,K(+)-adenosinetriphosphatase activity was seen in either opercular membrane or gill tissue. The results demonstrate an effect of prolactin on chloride cell size and provide a morphological correlate for decreased secretory activity of chloride cells following prolactin injections.
...
PMID:Effects of prolactin on chloride cells in opercular membrane of seawater-adapted tilapia. 165 57

The S-100 protein family constitutes a subgroup of Ca(2+)-binding proteins of the EF-hand type comprising three dimeric isoforms, S-100a0, S-100a and S-100b, plus a number of structurally related proteins displaying 28-55% homology with S-100 subunits. S-100 protein was discovered in 1965; yet, its biological functions have not been fully elucidated. The present report will review the putative biological roles of S-100 protein. Both intracellular and extracellular roles have been proposed for S-100 protein. Within cells, S-100 protein has been reported to regulate protein phosphorylation, ATPase, adenylate cyclase, and aldolase activities and Ca(2+)-induced Ca2+ release. Also, cytoskeletal systems, namely microtubules and microfilaments have been reported to be regulated by the protein in the presence of Ca2+. Some molecular targets of S-100 protein within cells, have been identified. This is the case with microtubule proteins, caldesmon, and a brain aldolase. S-100 protein has been reported to be secreted; extracellular S-100 protein can stimulate neuronal differentiation, glial proliferation, and prolactin secretion. However, the mechanisms by which S-100 is secreted and stimulates the above processes are largely unknown. Future research should characterize these latter aspects of S-100 biology and find out the linkage between its intracellular effects and its extracellular activities.
...
PMID:Perspectives in S-100 protein biology. Review article. 176 63

A study was made of the role of prolactin (PRL) in the regulation of thyroid function in intact animals and in those exposed to stress (swimming was used as physical exercise). A single daily dose of 125 micrograms of PRL per 100 g of body mass was injected subcutaneously in 0.5 ml of saline solution during a week to male rats (control: intact rats; injection of 0.5 ml of saline solution subcutaneously). Redox enzymes; succinate dehydrogenase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, NAD.H2 and NADP.H2, ATPase and monoamine oxidase, total protein, RNA and glycogen in glandular cells were investigated histochemically 24 h after the last injection of PRL or saline, 30 min., 1, 2, 3, 5 and 7 hours after swimming or right after complete fatigue (in the presence of experimental hyperprolactinemia). A conclusion has been made that one of the most important mechanisms of the adaptive effect of PRL is its ability to suppress thyroid function, thus decreasing the metabolism level, which results in reduction of oxygen consumption and improves body tolerance to stress.
...
PMID:[Metabolism of thyroid gland cells as affected by prolactin and emotional-physical stress]. 178 Feb 95

The effect of chronic high plasma corticosteroids' concentration upon renal function was studied in rats bearing a transplantable pituitary mammotropic tumor which produces large quantities of ACTH and prolactin (MtTF4S). Kidney splanchnomegaly and degenerative changes of renal cortex, particularly in proximal tubules, as well as cytolysis and appearance of vacuoles were noticed in tumor bearing rats. (Na+ + K+)-ATPase activity in renal plasma membranes decreased 67% in rats with a tumor secreting ACTH and prolactin, and 64% in rats with a tumor secreting growth hormone and prolactin when compared with controls. After adrenalectomy of MtTF4S rats, kidney weight as well as plasma concentrations of urea, sodium, chloride and phosphate ions were normalized indicating the involvement of adrenal glands in the development of disturbances in renal function.
...
PMID:Kidney damage in rats bearing an adrenocorticotropin and prolactin secreting tumor. 196 5

Small cultures of human amniotic cells were preincubated for 24 h. Human prolactin was then added to the medium. After a further short period of incubation the tubes were chilled, the medium removed and the cells rinsed with saline. The tubes then received cold Tris-sucrose and were frozen, to disrupt the cells. After thawing, adenosine triphosphatase (ATPase) and p-nitrophenyl phosphatase (PNPase) were measured. Buffer was added containing either ATP or PNP and the tubes were incubated for 30 min. Inorganic phosphate released from ATP and p-nitrophenol was measured spectrophotometrically. Prolactin stimulated both enzyme activities. The ATPase log dose-response curve was linear between approximately 12.5 and 200 mIU/l. It was inhibited by ouabain. Isobutyl-1-methylxanthine inhibited the ATPase but not the alkaline phosphatase activity. One of these human amniotic cell enzymes may provide the basis for a sensitive bioassay for human prolactin.
...
PMID:Enzyme activation of human prolactin: a potential basis for a bioassay. 247 90


1 2 3 4 5 6 7 8 9 10 Next >>

---