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

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

In freshwater-acclimated American eels (Anguilla rostrata LeSueur), ovine prolactin and grafts of the part of the pituitary gland containing the prolactin cells induced hypercalcemia. The hypercalcemia was associated with increased uptake of calcium from the water (resulting from increased influx and decreased efflux) and with enhanced high-affinity Ca2+-adenosinetriphosphatase (ATPase) activity in the gills, the putative biochemical correlate of the branchial Ca2+ pump. Kinetic analyses of ATPase-mediated Ca2+ transport in plasma membrane vesicles of branchial epithelium provided evidence that prolactin enhanced the maximum velocity of the Ca2+ pump. Prolactin treatments raised plasma cortisol levels slightly but significantly in eels. However, cortisol per se was not hypercalcemic in eels and did not stimulate the branchial Ca2+ pump. We conclude that the hypercalcemic potency of prolactin in fish relates to its stimulatory action on active Ca2+ transport in the gills.
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PMID:Calcitropic actions of prolactin in freshwater North American eel (Anguilla rostrata LeSueur). 252 94

To obtain more information on the role of prolactin and growth hormone during the parr-smolt transformation of Atlantic salmon, a population of fish in fresh water was sampled from January to June during two consecutive years. Gill Na+,K+-ATPase activity increased steadily during smoltification and a plasma thyroxine peak was observed 2-3 weeks before the gill Na+,K+-ATPase peak. On the basis of these two parameters, smoltification was considered complete in our populations in April 1985 and May 1986. Two peaks in plasma growth hormone levels occurred in 1986, one in mid-April and the second in mid-May. In both cases, these peaks coincided with a peak in plasma triiodothyronine and preceded the thyroxine peak by 1-2 weeks. Moreover, the second peak which lasted for 1 month coincided with maximal gill Na+,K+-ATPase activity. A decrease in plasma prolactin levels was observed during smoltification of Atlantic salmon in 2 consecutive years. During this period of decreasing and low plasma prolactin levels, gill Na+,K+-ATPase activity increased to its highest values. Atlantic salmon smolts were also directly transferred into seawater. After 2 days or more in seawater, plasma prolactin levels were not significantly different from those on Day 0, whereas in fresh water they showed large fluctuations. All these data indicate that growth hormone may play an important role in the development of hypoosmoregulatory activity. Increased hypoosmoregulatory ability also appears to be associated with low prolactin levels.
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PMID:Smoltification and seawater adaptation in Atlantic salmon (Salmo salar): plasma prolactin, growth hormone, and thyroid hormones. 254 14

The effect of prolactin on specific activities of adenosine triphosphatases (ATPases) in neural and gliar cells of cerebral cortex, cerebellum and pons-medulla of immature male bonnet monkeys was studied. Na+, K+ dependent ATPase was stimulated, while Mg2+ and Ca2+ dependent ATPase activities showed reduction in neural as well as glial cells of cerebral cortex and cerebellum. However, in pons-medulla, Na+, K+ and Mg2+ dependent ATPases showed the same trend in neural and glial cells, respectively, as in the other two regions. The data obtained reveal that prolactin has specific effect on different ATPases, in different regions of the brain.
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PMID:Influence of prolactin on neural and glial cellular adenosine triphosphatases in immature male bonnet monkeys (Macaca radiata, Geoffroy). 255 73

We have examined whether two recently isolated forms of tilapia (Oreochromis mossambicus) prolactin exert similar effects on osmoregulatory physiology. The effects of salinity, hypophysectomy, and replacement therapy with tilapia prolactins on whole-animal transepithelial potential (TEP), gill Na+, K+-ATPase activity, and plasma ions were determined. When intact fish adapted to 25% seawater (SW) were transferred to different salinities, TEP reached a steady state after 10 hr; TEP increased with increasing salinity from fresh water (FW) to 75% SW but was stable from 75 to 125% SW. Plasma osmolality, [Na+], and [Cl-] of these fish 24 hr after salinity change showed that fish in 100 and 125% SW had greater osmotic perturbation than those transferred to lower salinities. Following a 5-day recovery period in 25% SW, hypophysectomized fish transferred to FW for 10 hr had significantly lower TEP and plasma ion levels than either sham-operated fish or intact fish under the same conditions. Injection of hypophysectomized fish with "small" prolactin (tPRL177), "large" prolactin (tPRL188), or a combination of both (0.5 micrograms/g body weight) 22 hr and again 20 min prior to transfer from 25% SW to FW, restored TEP and plasma ion levels to those of sham-operated fish. Neither prolactin affected the TEP or plasma ions of sham-operated (intact) fish. Hypophysectomized fish had lower gill Na+,K+-ATPase activity than sham-operated fish in FW, but prolactin injections as described above did not affect gill Na+,K+-ATPase activity in either hypophysectomized or sham-operated fish. Our results indicate that the two forms of prolactin are indistinguishable with regard to several aspects of tilapia osmoregulation.
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PMID:Effects of salinity, hypophysectomy, and prolactin on whole-animal transepithelial potential in the tilapia Oreochromis mossambicus. 284 53

Addition of dimethyl sulfoxide (DMSO) and the mammotropic hormones prolactin, hydrocortisone, insulin, and estradiol to confluent cultures of the epithelial cell line Rat Mammary (Rama) 25 increases dramatically the formation of domes in the cell monolayer after 48-72 hr. Associated with the increase in doming is an increase of 24% in the activity of the Na+/K+ ATPase. Both Ca2+ (A23187) and Na+ (monensin, gramicidin J, melittin) ionophores can replace DMSO in inducing domes, whilst the K+ ionophore valinomycin inhibits doming. However, there are no synergistic nor additive effects, respectively, with suboptimal or optimal concentrations of A23187 and melittin together. Ouabain, at concentrations which inhibit the Na/K ATPase in vitro, and amiloride, at concentrations reported to inhibit the passive transport of Na+, both inhibit completely the formation of domes induced by DMSO, A23187, and melittin. EGTA, however, inhibits only the induction of doming by DMSO and A23187; it is without effect with melittin. A23187 and melittin induce the major polypeptide changes that occur in doming cultures with DMSO, and most of these changes are also inhibited with ouabain. It is suggested that one possible interpretation of the findings is that the induction of doming by DMSO in Rama 25 cells occurs by means of sequential increases in Ca2+ and Na+ influxes into the cell, and that the increased intracellular concentration of Na+ so produced stimulates the Na+/K+ ATPase, with a net effect of pumping liquid beneath the cellular monolayer.
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PMID:The effect of ionophores and related agents on the induction of doming in a rat mammary epithelial cell line. 298 89

The effect of rat prolactin on rat renal Na+-K+-ATPase activity was investigated by a cytochemical technique. Rat prolactin caused stimulation of Na+-K+-ATPase activity only in the outer medulla of the kidney, and not in renal cortical structures. Peak enzyme activity in cultured rat renal segments occurred after tissue had been exposed to rat prolactin for 2 min, and the time of maximal stimulation did not vary with the concentration of prolactin. There was a curvilinear response in Na+-K+-ATPase activity over the rat prolactin concentration range, 0.04-40 ng/l, but higher prolactin concentrations caused inhibition of enzyme activity. Na+-K+-ATPase response was totally blocked by specific rat prolactin antiserum. Human prolactin had no consistent effect on rat medullary Na+-K+-ATPase activity. Addition of specific tri-iodothyronine and arginine vasopressin antisera to rat prolactin was without effect, confirming that the stimulatory action of rat prolactin on Na+-K+-ATPase was not due to contamination with these hormones which are known to stimulate this enzyme.
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PMID:Prolactin stimulates Na+-K+-ATPase activity located in the outer renal medulla of the rat. 300 25

Prolactin has been known to affect the water and electrolyte balance. Because increased lens hydration has been shown to be a common phenomenon in most, if not all types of cataracts, we have been interested in investigating a possible role of prolactin in sugar cataract induction and progression. For this study, we have used morphological and biochemical approaches. The prolactin delivery method involved intraperitoneal implantation of one or more pellets in Sprague-Dawley female rats. Following implantation of the desired number of prolactin or control (nonprolactin) pellets, animals were either fed galactose and lab chow, or lab chow diet. Gross morphological observations of whole lenses, slit-lamp examination of lenses and light microscopic analysis of lens sections showed that in the galactose-fed prolactin group, galactose associated alteration progressed faster and total opacification (mature cataract development) was achieved earlier than in the nonprolactin group. The levels of galactose and dulcitol were higher in the lenses of galactose-fed prolactin treated rats as compared to lenses from nonprolactin (control) rats. No significant difference in lens Na+-K+ ATPase activity between the prolactin and nonprolactin group was observed. Our results indicate that prolactin accelerates galactose-induced cataractogenesis in rats.
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PMID:Effect of prolactin on galactose cataractogenesis. 303 35

To test prolactin (PRL) action on osmoregulation in mammals, we evaluated in the rat the effect of this hormone on a major enzyme in renal regulation of water and electrolyte: renal Na-K-ATPase. Enzyme activity was determined by cytochemistry in medullary ascending limb (MAL) and distal convoluted tubule (DCT) from rats treated either by bromocriptine, or by PRL. Three hours after a bromocriptine injection (0.1 mg/100 g IP) a significant decrease of Na-K-ATPase activity is observed in both MAL (80% of control values, p less than 0.001) and DCT (78% p less than 0.01). Reciprocally, a significant (p less than 0.001) increase in enzyme activity is induced 3 h after a single PRL injection (140 micrograms/100 g IM), in both segments (MAL: 165%, DCT: 172% of control activities) and persists 6 h after the injection (MAL: 130%, DCT: 118%). Na-K-ATPase activity was correlated to plasma PRL levels (r = 0.78 in DCT, r = 0.89 in MAL). A direct effect of PRL on the tubule is suggested by results from experiments in which PRL, at various concentrations, is added in vitro on renal slices before Na-K-ATPase activity measurements. The increase in Na-K-ATPase activity exhibits a log-dose dependency with PRL concentration (p less than 0.01) and is still observed when AVP antagonist is added before PRL incubation, ruling out the possible role of AVP contamination of PRL. These results suggest a direct effect of PRL on renal Na-K-ATPase in MAL and DCT.
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PMID:Effects of prolactin on Na-K-ATPase activity along the rat nephron. 303 52

In order to elucidate the mechanism of pregnancy-induced hypertension (PIH) from the point of view of vascular resistance, we measured the intracellular Na+ concentrations and the membrane Na+ effluxes using red blood cells from normal pregnant females and patients with PIH. We also discussed the influences of hormones such as estrogen, progesterone, dehydroepiandrosterone sulfate (DHAS), hydrocortisol, human placental lactogen (hPL), human chorionic gonadotropin (hCG), and prolactin and parathyroid hormone (PTH) on the membrane Na+ effluxes. The intracellular Na+ concentrations were lower and the Na+-K+-ATPase activities were slightly higher both in the luteal phase and in the first trimester of normal pregnancy than those in the follicular phase, after which the former gradually increased and the latter gradually decreased until term to the mean values of those in the whole menstrual period. In mild PIH, the intracellular Na+ concentrations were not significantly increased, and the Na+-K+-ATPase activities were significantly increased compared to those in the third trimester of normal pregnancy, which suggests the compensatory increase of the Na+-K+-ATPase activities as opposed to the increase of the intracellular Na+ concentrations. In severe PIH, the intracellular Na+ concentrations were significantly increased compared with those in the third trimester of normal pregnancy and slightly increased compared with those in mild PIH, whereas the Na+-K+-ATPase activities were slightly decreased compared with those in mild PIH, which indicates a breakdown of the compensatory increase of the Na+-K+-ATPase activities. The intracellular Na+ concentrations in PIH are significantly correlated to diastolic pressure, systolic pressure and mean blood pressure. When the male red blood cells were incubated with the hormone, dose-dependently the Na+-K+-ATPase activities were significantly elevated by hydrocortisol and slightly elevated by progesterone and hPL, and they were significantly depressed by estrogen and prolactin and slightly depressed by PTH. These results suggest that the peripheral vascular resistance might be increased in the third trimester of normal pregnancy compared with that in the first trimester because the intracellular Na+ concentrations were elevated, and the Na+-K+-ATPase activities in the cell membrane were decreased along the course of pregnancy as a result of the effects of various hormones in the maternal blood.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[A study on the membrane Na+ efflux of pregnancy-induced hypertension (PIH)]. 320 19

Antibodies against a lysosomal membrane antigen (A-Ly-M) have recently been obtained and characterized (Reggio, H., D. Bainton, E. Harms, E. Coudrier, and D. Louvard, 1984, J. Cell Biol., 99:1511-1526). They recognize a 100,000-mol-wt antigen immunologically related to a purified [H+,K+]ATPase from pig gastric mucosa. In the present study, we have localized this antigen during adsorptive endocytosis in rat prolactin cells in culture using cationized ferritin (CF) as a tracer. CF was rapidly internalized (after 5 min) in coated pits and vesicles that were labeled by antibodies against clathrin. The tracer was then delivered (after 15 min) to vacuoles and multivesicular bodies. These structures were labeled with A-Ly-M. These organelles were devoid of acid phosphatase activity. At later stages (after 30 min) CF was observed within larger structures that were strongly stained by A-Ly-M and displayed a strong acid phosphatase activity. These findings clearly indicate that A-Ly-M react with prelysosomal and lysosomal compartments involved in the endocytic pathway in cultured prolactin cells. The membrane of these structures therefore contains antigenic determinant(s) related to the 100,000-mol-wt polypeptide. Our results suggest that the prelysosomal structure stained by A-Ly-M may represent in GH3 cells the acidic prelysosomal compartment recently described in the early steps of endocytosis in other cell types (Tycko, B., and F. R. Maxfield, 1982, Cell, 28:643-651).
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PMID:Antibodies against a lysosomal membrane antigen recognize a prelysosomal compartment involved in the endocytic pathway in cultured prolactin cells. 397 94


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