Subcellular localization of oxytocin in the ovine corpus luteum

1985 ◽  
Vol 63 (4) ◽  
pp. 309-314 ◽  
Author(s):  
G. E. Rice ◽  
G. D. Thorburn
Keyword(s):  
Subcellular Localization ◽  
Physicochemical Properties ◽  
Corpus Luteum ◽  
Density Gradient Centrifugation ◽  
Secretory Granules ◽  
Gradient Centrifugation ◽  
Particulate Fraction ◽  
Dense Granules ◽  
Oxytocin Release ◽  
Midluteal Phase

The subcellular localization of oxytocin within the corpus luteum of sheep was investigated using differential and density gradient centrifugation. Oxytocin was associated with a particulate fraction which sedimented to a density of 1.054 – 1.061 g/mL. The exclusion of [3H]oxytocin from this particulate fraction is indicative that particulate oxytocin represents endogenous compartmentalization. Particulate oxytocin, incubated in buffered medium at 37 °C, was stable for up to 1 h and the release of oxytocin was not affected by the pH of the incubation medium, over the range 5.5 – 8.5. Oxytocin release, however, was stimulated by incubating particle-bound oxytocin in buffered medium of low osmolality (<200 mosmol). These data are similar to the physicochemical properties reported for peptide-containing neurohypophysial secretory granules. Ultrastructural analysis of oxytocin-containing fractions revealed the presence of electron-dense granules (diameter, 200–250 nm). These data are suggestive that oxytocin, in the corpus luteum of sheep, is contained within a population of secretory granules which occur in high numbers during the midluteal phase of the oestrous cycle.

Comparison of particle-associated progesterone and oxytocin in the ovine corpus luteum

1986 ◽  
Vol 108 (1) ◽  
pp. 109-116 ◽  
Author(s):  
G. E. Rice ◽  
G. Jenkin ◽  
G. D. Thorburn
Keyword(s):  
Corpus Luteum ◽  
Biogenic Amines ◽  
Density Gradient ◽  
Subcellular Distribution ◽  
Incubation Medium ◽  
Density Gradient Centrifugation ◽  
Secretory Granules ◽  
Gradient Centrifugation ◽  
Biochemical Characteristics ◽  
Oxytocin Release

ABSTRACT The subcellular distribution of progesterone and oxytocin within the ovine corpus luteum was investigated using differential and density gradient centrifugation. Progesterone and oxytocin were associated with particles which sedimented to a density of 1·049–1·054 g/ml and 1·054–1·061 g/ml respectively. Particle-associated progesterone did not, however, display physical or biochemical characteristics consistent with its storage within secretory granules. When particle-associated progesterone was incubated in HEPES buffer at 37 °C, 70% of the total progesterone was recovered in the incubation medium. The remaining stable particle-associated progesterone was not affected by treatments which stimulated oxytocin release and which have been shown to cause the release of peptides and biogenic amines from secretory granules. These results suggest that particle-associated progesterone represents the intercalation of progesterone into cell membranes and they do not support the hypothesis that progesterone is stored, in a protein-bound form, in luteal secretory granules. J. Endocr. (1986) 108, 109–116

Adenine Phosphoribosyltransferase Activity in Mitochondria of Catharanthus roseus Cells

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1288-1289 ◽  
Author(s):  
Fumiko Hirose ◽  
Hiroshi Ashihara
Keyword(s):  
Subcellular Localization ◽  
Density Gradient ◽  
Catharanthus Roseus ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Particulate Fraction ◽  
Adenine Phosphoribosyltransferase ◽  
Percoll Density Gradient Centrifugation ◽  
Percoll Density Gradient

Abstract Subcellular localization of adenine phosphoribosyltrans­ferase was examined in Catharanthus roseus cells. At least 13% of the activity was observed in the particulate fraction with the rest observed in the cytosol. Both differential and Percoll density gradient centrifugation indicated that particulate adenine phosphoribosyltransferase was predominantly located in the mitochondria.

Characterization of particle-associated choriomammotrophin and progesterone in ovine placentomes

1986 ◽  
Vol 111 (2) ◽  
pp. 217-NP ◽  
Author(s):  
G. E. Rice ◽  
G. D. Thorburn
Keyword(s):  
Colloidal Silica ◽  
Specific Activity ◽  
Density Gradient Centrifugation ◽  
Secretory Granules ◽  
Gradient Centrifugation ◽  
Physicochemical Characteristics ◽  
Dense Granules ◽  
Endocrine Tissues

ABSTRACT The subcellular distribution and compartmentalization of choriomammotrophin (CM) and progesterone within ovine placentomes was investigated using differential and density gradient centrifugation techniques. Approximately 67% of placental CM and 45% of progesterone was associated with subcellular particles. The 10 000 g particulate fraction contained the highest specific activity of both CM and progesterone (19·1 ±3·8 (s.e.m.) μg/mg and 71·5 ± 9·2 pmol/mg protein respectively). This fraction was also shown to contain electron-dense granules with morphology similar to that of hormone-containing secretory granules isolated from other endocrine tissues. Particle-associated CM sedimented to a density of 1·051–1·054 g/ml in colloidal silica gradients and displayed physicochemical characteristics consistent with its storage in secretory granules. During in-vitro incubations, particle-associated CM was stable for up to 90 min, but dissociated when incubated in hypoosmotic medium. Particulate progesterone, which was also present in the CM-rich fraction and was stable for up to 90 min of incubation, was not affected by decreasing the osmolality of the incubation medium. These data suggest that ovine CM (but not progesterone) is stored within a population of secretory granules located within placentomes. J. Endocr. (1986) 111, 217–223

Noradrenaline storage particles in splenic nerve

1971 ◽  
Vol 261 (839) ◽  
pp. 313-317 ◽  
Keyword(s):  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
The Other ◽  
Particulate Fraction ◽  
Degree Of Contamination ◽  
Pure Preparation

Our present work is aimed at obtaining information about noradrenaline storage particles in splenic nerve—both of axonal and terminal derivation. These experiments have been carried out using differential and density gradient centrifugation techniques. Because of difficulties in obtaining an absolutely pure preparation of noradrenaline vesicles (Stjärne 1966) we have not attempted a purification of the particles but have used the other possible alternative as first proposed by de Duve (1964). This method involves the localization of a particle, in fractions obtained by centrifugation, by estimation of an internal constituent; the degree of contamination of a particulate fraction can be assessed by estimation of constituents of other known particles. By this method it is then possible to determine which constituents belong to any one particle.

Specific binding sites for progesterone in subcellular fractions of the porcine corpus luteum

1994 ◽  
Vol 142 (1) ◽  
pp. 101-110 ◽  
Author(s):  
G S Menzies ◽  
T A Bramley
Keyword(s):  
Corpus Luteum ◽  
Early Pregnancy ◽  
Binding Sites ◽  
Luteal Phase ◽  
Secretory Granules ◽  
Buoyant Density ◽  
Subcellular Fractions ◽  
Particulate Fraction ◽  
Luteal Cell

Abstract Subcellular fractionation of porcine corpus luteum (CL) homogenates on continuous sucrose gradients has previously demonstrated that most of the endogenous progesterone of the CL was associated with a unique particulate fraction. Exogenous radiolabelled steroids were also sequestered with some specificity by this fraction. We now report that this particulate fraction is capable of binding high levels of exogenous 3H-labelled progesterone (and pregnenolone) in vitro, but only in the presence of the saponin, digitonin. Binding was dependent on the pH, temperature and duration of incubation, and showed specificity and high affinity for progesterone (Kd, 79 nm). Androgens, oestrogens and pregnenolone competed for porcine luteal [3H] progesterone binding sites, but only at much higher concentrations, whereas cholesterol, a number of progesterone receptor agonist and antagonist analogues and inhibitors of 3β-hydroxysteroid dehydrogenase and C17-hydroxylase/C17,20-lyase did not compete. Analysis of profiles for a number of luteal cell-surface membrane and intracellular organelle markers confirmed previous studies showing the association of an NADH-cytochrome C reductase with this fraction. Moreover, the content of endogenous progesterone associated with particulate subcellular fractions isolated from porcine granulosa cell (GC) and CL homogenates at different stages of the luteal phase and early pregnancy waxed and waned with the stage of the luteal phase (and the secretory activity of the CL). Binding of [3H]progesterone in vitro equilibrated at the same buoyant density as endogenous progesterone: levels of both were highest during the mid-luteal phase and during early pregnancy, lower in early and late luteal CL, and undetectable in corpora albicantia. In contrast, relaxin secretory granules were readily resolved from progesterone binding sites. We propose that these particulate progesterone binding sites may be involved in the sequestration and/or packaging of newly-synthesized steroid for secretion by the luteal cell, or may mediate actions of progesterone within the luteal cell. Journal of Endocrinology (1994) 142, 101–110

scholarly journals ISOLATION AND BIOCHEMICAL STUDY OF SECRETORY GRANULES FROM RAT PITUITARY GLANDS

1962 ◽  
Vol 15 (2) ◽  
pp. 159-172 ◽  
Author(s):  
J. F. Perdue ◽  
W. H. McShan
Keyword(s):  
Alkaline Protease ◽  
Density Gradient Centrifugation ◽  
Biochemical Study ◽  
Secretory Granules ◽  
Gradient Centrifugation ◽  
Succinic Dehydrogenase ◽  
Acid Protease ◽  
Alkaline Phosphatases ◽  
Rat Pituitary ◽  
Pituitary Glands

Secretory granules from anterior pituitary glands of young adult male castrate rats were isolated by differential centrifugation, microfiltration, and discontinuous density gradient centrifugation. The granules were obtained as pellets, sectioned, and studied with the electron microscope. A major part of the gonadotropin and a substantial amount of the TSH were associated with the isolated granules. Negligible amounts of growth hormone and prolactin were present as contaminants. Succinic dehydrogenase, glucose-6-phosphatase, acid protease, and acid and alkaline phosphatases were not found in the granules. Alkaline protease was the only enzyme found to be associated with the granules, and it is suggested, in the light of these results, that the alkaline protease may be involved in the release of the hormones.

scholarly journals Peroxisomal localization of glucose-6-phosphate dehydrogenase and pyrophosphate-stimulated dihydroxyacetone-phosphate acyltransferase in mouse kidney

1987 ◽  
Vol 244 (2) ◽  
pp. 443-448 ◽  
Author(s):  
B N Patel ◽  
M I Mackness ◽  
M J Connock
Keyword(s):  
Subcellular Localization ◽  
Dehydrogenase Activity ◽  
Inorganic Phosphate ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Mouse Kidney ◽  
Dihydroxyacetone Phosphate ◽  
Ph Optimum ◽  
Dependent Activity ◽  
Glucose 6 Phosphate Dehydrogenase

1. The subcellular localization of dihydroxyacetone-phosphate acyltransferase (DHAPAT) (assayed in the presence of pyrophosphate) and glucose-6-phosphate dehydrogenase (NADP+-dependent) activity in mouse kidney was investigated by density-gradient centrifugation. 2. DHAPAT has a predominantly peroxisomal distribution, and the activity in purified peroxisomes is stimulated by various organic and inorganic phosphate-containing compounds. The pH optimum is acid. 3. Approx. 10% of the cellular NADP+-dependent glucose-6-phosphate dehydrogenase activity is associated with peroxisomal fractions and may provide a source of NADPH for the peroxisomal reduction of acyl-dihydroxyacetone phosphate formed by DHAPAT activity.

FATE OF NEUROHYPOPHYSIAL GRANULE MEMBRANES AFTER SECRETION IN THE RAT: GENERATION OF A NEW APPARENT ORGANELLE BY FREEZING AND THAWING SECRETORY GRANULES

1981 ◽  
Vol 88 (1) ◽  
pp. 115-123
Author(s):  
JEAN H. LACEY ◽  
B. T. PICKERING
Keyword(s):  
Density Gradient Centrifugation ◽  
Secretory Granules ◽  
Gradient Centrifugation ◽  
Hormone Release ◽  
Freezing And Thawing ◽  
Granule Fraction ◽  
Two Peaks ◽  
Stimulation Of

The contents and membranes of the secretory granules in the rat neurohypophysis were labelled in vivo with [35S]cysteine and [3H]choline respectively. Density-gradient centrifugation of the labelled granules showed the membrane label to be distributed largely between two peaks: one associated with intact granules and one with the characteristics of empty granule envelopes. Stimulation of hormone release in vitro led to the movement of membrane label from the intact granule fraction to the other one, consistent with the recapture of membrane as large vesicles. Freezing and thawing the crude granule fraction, ostensibly to aid osmotic fracture, produced a single membrane component with a density intermediate between the two original fractions.

Arginine esterase from isolated dog prostate secretory granules is fully active enzymatically

1985 ◽  
Vol 63 (12) ◽  
pp. 1603-1607 ◽  
Author(s):  
Gilles Frenette ◽  
Jean Y. Dubé ◽  
Jean R. Marcotte ◽  
Roland R. Tremblay
Keyword(s):  
Enzymatic Activity ◽  
Seminal Plasma ◽  
Density Gradient Centrifugation ◽  
Secretory Granules ◽  
Gradient Centrifugation ◽  
Protein Substrates ◽  
Inactive Form ◽  
Specific Enzymatic Activity ◽  
The One

We have isolated secretory granules from dog prostate homogenates and have determined whether a major portion of arginine esterase was localized in this fraction and if it was enzymatically active. Secretory granules were purified by density gradient centrifugation on sucrose, metrizamide, or Percoll. A major proportion of whole prostate homogenate arginine esterase was found in the granule fractions. Furthermore, the specific enzymatic activity in the granules was similar to the one observed in seminal plasma. No evidence could be found for the existence of significant amount of a zymogen inactive form of arginine esterase. These results suggest that arginine esterase could be active within the secretory granules in vivo and that it could hydrolyze protein substrates contained in this organelle.

Physicochemical properties of Nebraska calf diarrhea virus hemagglutinin

1978 ◽  
Vol 24 (11) ◽  
pp. 1425-1430 ◽  
Author(s):  
F. R. Bishai ◽  
P. Blaskovic ◽  
D. Goodwin
Keyword(s):  
Physicochemical Properties ◽  
Ethyl Alcohol ◽  
Methyl Alcohol ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Cesium Chloride ◽  
Effect Of Temperature ◽  
Diarrhea Virus ◽  
Calf Diarrhea ◽  
Virus Morphology

Highly purified Nebraska calf diarrhea virus (NCDV)was prepared by cesium chloride density gradient centrifugation. The effect of temperature, pH, different concentrations of formaldehyde, chloroform, ether, ethyl alcohol, and methyl alcohol on NCDV hemagglutinin and virus morphology was studied. NCDV hemagglutinin was inactivated by temperature, pH 2.0, chloroform, ethyl alcohol, and methyl alcohol.

Sign in / Sign up

Export Citation Format

Share Document