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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tissue pieces from the wall (i.e. tunica albuginea with adjacent theca externa) of human follicles were incubated with and without various hormones and their potential influence upon the collagenolytic activity was evaluated. Following incubation the collagenase activity was determined in the incubation medium by measurement of the hydrolytic activity against the synthetic peptide 2,4-dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg-OH. Stimulated collagenolytic activity was seen in the presence of relaxin and oxytocin whereas prostaglandin E2, prostaglandin F2 alpha, progesterone and 17 beta-estradiol were without effect. It is concluded that the stimulated collagenolytic activity induced by relaxin and oxytocin may be of importance for the degradation of collagen which occurs prior to follicular rupture.
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PMID:Hormonal effects on collagenolytic activity in the isolated human ovarian follicular wall. 301 21

Nerve terminals were isolated from sheep posterior pituitary lobes using a collagenase digestion technique. Freshly dispersed terminals, and terminals cultured for up to 3 days were examined by immunofluorescence microscopy. Immunohistochemical results suggested the presence of immunoreactive-neurophysin, -oxytocin and -vasopressin in membrane-bound structures. Membrane depolarization induced by high concentrations of potassium ions stimulated oxytocin release. This release was attenuated in the absence of calcium ions. The calcium ionophore, A23187, was also an effective stimulator of oxytocin secretion. These data suggest that neurohypophysial nerve terminals prepared by a collagenase dispersion procedure may be suitable for the investigation of posterior pituitary secretion mechanisms.
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PMID:Isolation and properties of sheep neurohypophysial nerve terminals. 309 Apr 71

Testicular interstitial cells, from rats aged 35 days, were dispersed with collagenase and separated through Percoll into 5 fractions (I-V); fraction I being the least dense. Measurement of basal testosterone production, histo-enzymological staining for 3 beta-hydroxysteroid dehydrogenase activity and electron microscopy indicated that the majority of Leydig cells were found in fraction IV (corresponding to a density of 1.076-1.097 g/ml). In addition, cells from this fraction responded to hCG treatment in a dose-dependent manner on day 0 and remained responsive after being cultured for 1 day. Immunostaining for oxytocin indicated that this fraction also contained the majority of the oxytocin-immunoreactive cells. On day 1 of culture, 56% of the cell population from fraction IV were positively stained for the steroidogenic enzyme and 75% immunoreactive for oxytocin. This overlap indicates that the Leydig cells were also the oxytocin immunoreactive cells.
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PMID:Oxytocin in Leydig cells: an immunocytochemical study of Percoll-purified cells from rat testes. 316 20

Steroidogenic cells in the corpus luteum of the ferret (Mustela putorius) during early (Days 6 and 13) to midpregnancy (Day 24) were characterized using electron microscopy, immunocytochemical localization of neurophysin, and smears of dispersed cells obtained by dissociating luteal cells with collagenase. The latter were stained for 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity, and the diameters of the cells were determined with an ocular micrometer. Very small cells (less than 12 microns) stained negative for 3 beta-HSD, occurred in clumps of 5-50 cells, and were presumed to be primarily endothelial cells. 3 beta-HSD-positive cells covered a wide spectrum of sizes ranging from 14 to 56 microns and did not exist as two discrete populations. The ratio of small (less than 25 microns) to large (greater than 25 microns) cells was 1.86:1.0 on Day 6, with the 17- to 20-microns cell size class predominating. On the day of implantation (Day 13), about 75% of the cells ranged from 26 to 50 microns, with the 29-microns size predominating. By Day 24, the ratio of small-to-large cells had declined to 0.15. Nearly 90% of the cells were in the 26- to 56-microns range, the predominant size being 35 microns. All size classes of luteal cells stained negative for neurophysin on all 3 days of pregnancy studied. Luteal cells obtained on Days 6, 13, and 24 of pregnancy failed to reveal any evidence of mitosis after in vivo or in vitro colchicine treatment. We interpret these results as indicating that the 3 beta-HSD-positive luteal cells of ferrets progressively increase in size as small luteal cells complete their differentiation from granulosa cells and ultimately form larger luteal cells with somewhat different ultrastructural characteristics.
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PMID:Size distribution of ferret luteal cells during pregnancy. 321 87

Corpora lutea from cyclic ewes were dissociated by collagenase and trypsin/EGTA treatments, and enriched fractions of small and large luteal cells were prepared on gradients of Ficoll. These fractions were incubated separately or remixed before incubation. Colchicine, cytochalasin B and the calcium channel-blocker verapamil significantly reduced progesterone production by both small and large luteal cell fractions, while isoprenaline stimulated an increase in progesterone production by large luteal cell fractions only. When fractions of small and large luteal cells were remixed, no more and no less progesterone was produced than would have been predicted from equivalent fractions incubated separately. There was therefore no evidence of synergism between small and large luteal cells in the production of progesterone. Prostaglandin F-2 alpha, which can inhibit LH-stimulated progesterone production by ovine luteal tissue in vitro, had no effect on LH-stimulated progesterone production by small luteal cell fractions, but significantly inhibited that by enriched fractions of large luteal cells. Since large luteal cell fractions were contaminated with small luteal cells, which are probably responsible for the progesterone-secretory response of these fractions to LH, it was concluded that the inhibition of LH-stimulated progesterone production by small luteal cells is dependent on the presence of large luteal cells. Oxytocin added to large and small luteal cell fractions did not affect progesterone production by either fraction. It was therefore concluded that the inhibitory action of PGF-2 alpha on LH-stimulated progesterone production may require the interaction of large and small luteal cells, but that oxytocin is not likely to be an intermediary in this interaction.
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PMID:Do small and large luteal cells of the sheep interact in the production of progesterone? 386 69

To investigate whether particles deposited in the vagina translocate to the oviducts, 0.3 ml of a 4% bone black suspension was deposited in the posterior vaginal fornix of each of five cynomolgus monkeys (Macaca fascicularis) during their mid-menstrual cycle. Simultaneously, each animal received 10 units of oxytocin by intramuscular injection. The oviducts of three animals were removed 1 hr after administration of the bone black, while those of the remaining two animals were removed 72 hr after dosing. The removed oviducts were flushed with Hank's solution and then with collagenase solution. The solutions were collected in clean vials and filtered. The filters were examined for bone black particles by light microscopy, as were filters through which solution blanks (negative controls) had been passed. Particles resembling bone black were found on all filters. There were no appreciable differences in the number or shape of these particles between the solution-blank filters and the oviduct-flush filters. The particles on both the solution-blank filters and on the oviduct-flush filters probably originated from environmental contamination by ubiquitous carbon particles. While these results suggested that no translocation took place, translocation could not be ruled out with certainty in the absence of quantitative analyses. A more definitive pilot study was then conducted with two dosed monkeys and one control, using talc labelled by neutron activation to circumvent the problem of environmental contamination. Gamma-Ray analysis of tissue and peritoneal lavage samples for the radionuclides 46Sc, 59Fe and 60Co indicated that no measurable quantities (i.e. greater than 0.5 micrograms) of talc translocated from the deposition site in the vagina to the uterine cavity and beyond.
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PMID:Do particles translocate from the vagina to the oviducts and beyond? 404 89

Myoepithelial and secretory cells from the mammary gland of the lactating rat have been isolated, purified, and characterized. Mammary tissue was dissociated with collagenase into basket-like networks of myoepithelial cells and single secretory cells. Because of their larger size, the myoepithelial cell networks could be separated from other mammary and blood cells by differential centrifugation. Isolated secretory cells were purified by isopycnic centrifugation in 25% bovine serum albumin. The purified myoepithelial and secretory cells were viable, as shown by the incorporation of 32P into distinct macromolecules that were separable by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both myoepithelial and secretory cells retained their characteristic morphology after isolation and purification, as shown by light, transmission, and scanning electron microscopies. The isolated myoepithelial cells were unique and, thus, distinguishable from other mammary cells in a number of respects; they 1) contracted in response to the addition of oxytocin, 2) bound [3H]oxytocin specifically, 3) accounted for the content of alkaline phosphatase and [Na+ + K+]ATPase in mammary tissue, and 4) reacted specifically with antiserum prepared against purified myoepithelial cells. The purified secretory cells were unique in possessing glucose-6-phosphate dehydrogenase activity. The different cell markers not only gave independent estimates of the purity of the cell fractions, but they also may be helpful in identifying mammary cells in stages of differentiation and neoplastic transformation.
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PMID:Purification and characterization of mammary myoepithelial and secretory cells from the lactating rat. 624 56

Experiments were performed to determine the ability of isolated cells from human amnion, chorion, and decidua to hydrolyze estrone sulfate (E1S) to free estrone (E1) and estradiol (E2). Tissues were obtained from eight women after spontaneous onset of labor and vaginal delivery and from eight women undergoing elective cesarean section at term before the onset of labor. The tissues were obtained immediately after delivery, dispersed into isolated cell preparations using 0.05% collagenase, and incubated in Krebs-Ringer bicarbonate at 37 degrees C for 4 h. E1 and E1S were measured by specific RIAs. All three tissues from both patient groups produced E1 and E2 in a dose-dependent fashion from the E1S precursor. In both patient groups, chorion and decidua cells produced significantly more E1 and E2 than amnion cells. The chorion cells from the spontaneous labor group produced significantly more E1 than chorion cells from the cesarean section group. The chorion and decidua cells from the spontaneous labor group produced significantly more E2 than corresponding cells from the cesarean section group. The hydrolysis of E1S to E1 and E2 was significantly inhibited in a dose-dependent fashion by increasing concentrations of oxytocin and (Bu)2cAMP. Dispersed cells from amnion, chorion, and decidua also converted [3H]E1S to radiochemically pure [3H]E1. Chorion and decidua cells were significantly more active in this respect than amnion. The presence of excessive amounts of dehydroepiandrosterone sulfate (DHAS) did not significantly alter this reaction. All three tissues also hydrolyzed [3H]dehydroepiandrosterone sulfate, but in chorion and decidua, this activity was significantly less than the hydrolysis of [3H]E1S. We conclude that human amnion, chorion, and decidua possess the capability to hydrolyze E1S to free estrogen and that this activity in chorion and decidua is increased after spontaneous vaginal delivery. It is possible that this activity and its regulation are important factors in the local synthesis of free estrogen, which, in turn, may influence myometrial contractility.
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PMID:Formation of unconjugated estrogens from estrone sulfate by dispersed cells from human fetal membranes and decidua. 670 90

The response of mammary myoepithelial cells to oxytocin was studied by monitoring the level of phosphorylation of the 20,000 mol wt light chain of myosin. Myoepithelial cells were obtained by collagenase dispersion of involuted rat mammary tissue. The cells were equilibrated with [32P]orthophosphate, and then stimulated with oxytocin. Phosphorylated proteins were separated by polyacrylamide gel electrophoresis, and incorporation of 32P into the proteins was detected by autoradiography. Nanomolar concentrations of oxytocin caused a 3-fold increase in the level of phosphorylation of the myosin light chain within 0.5 min. When the cells were incubated with oxytocin in a calcium-free medium, there was only a transient phosphorylation of myosin. However, readdition of calcium to these cells resulted in phosphorylation of the myosin light chain. The results suggest that calcium is involved in the intracellular events following stimulation of the cells with oxytocin.
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PMID:Phosphorylation of myosin in mammary myoepithelial cells in response to oxytocin. 707 45

A patch-clamp study of Ca2+ currents and spectrofluorometric detection of the intracellular Ca2+ concentration [Ca2+]i was performed on porcine myometrial cells that had been isolated by collagenase. Isolated myometrial cells were the typical long cylinder shape. The main length and diameter of myometrial cells were 505 +/- 20 and 11 +/- 0.5 microns (n = 40), respectively, in the prepartum period and 265 +/- 22 and 7 +/- 0.4 microns (n = 40), respectively, in the luteal phase. Immunocytochemistry with an antibody against desmin stained 90% of the cells positively, and about 95% of the cells excluded Trypan blue dye. The basal [Ca2+]i of myometrial cells in the luteal phase and the prepartum period was 119 +/- 12 (n = 30) and 154 +/- 31 nmol l-1 (n = 48), respectively. In prepartum myometrial cells, oxytocin (10(-7) mol l-1) and carbachol (10(-4) mol l-1) increased [Ca2+]i in a biphasic pattern, with a sharp peak followed by a plateau. In cells in the luteal phase, adrenaline (10(-7) mol l-1) plus propranolol (10(-6) mol l-1) produced a biphasic increase in [Ca2+]i. However, in the absence of propranolol, the increase in [Ca2+]i by adrenaline was small. Prostaglandin F2 alpha (10(-6) mol l-1) induced a monophasic increase in the [Ca2+]i in cells in the luteal phase. By depolarizing the cells from -30 to +50 mV from a holding potential of -50 mV, Ca2+ currents were evoked with a threshold at -20 mV, reaching a maximum between 10 and 30 mV.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of freshly dispersed porcine myometrial cells: evidence for voltage-dependent Ca2+ channels and regulatory receptors. 779 25


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