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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Electrophysiological studies were performed on single smooth muscle cells isolated from the vas deferens of the rat. The tissue was preincubated in Ca-free modified Tyrode's solution for 1 h and then transferred to a high-K solution for 1 h. It was next minced and treated with the enzyme solution composed of 600-800 unit/ml collagenase and 40 unit/ml elastase. The procedure yielded about 50% spindle shaped Ca-tolerant cells (100-250 microns in length and about 10 microns in diameter). These cells could contract during the superfusion with the solutions containing 10(-8) to 10(-3) M norepinephrine (NE) or adenosine triphosphate (ATP). The cells isolated from the epididymal portion were more sensitive to norepinephrine than were those from the prostatic part. Their basic electrical properties were studied using tight-seal suction electrode technique. The cells had resting potentials around -40 mV and their input resistance was about 0.8 G omega. Action potentials could be evoked by application of depolarizing current. During whole cell voltage clamp, an inward current followed by an outward current was recorded when 800 ms pulses from a holding potential of -60 mV to test potentials positive than -40 mV were applied. The transient outward current generally recorded in other smooth muscle cells was not seen in these cells. The amplitude of the inward current was Ca dependent and sensitive to a Ca antagonist, nicardipine, indicating that Ca ion is the main carrier of this component of the current. When the pipette was filled with Cs-containing solution, the outward current was abolished.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Contractile response and electrophysiological properties in enzymatically dispersed smooth muscle cells of rat vas deferens. 243 37

A reproducible cell culture system is described that allows the study of adipose conversion in fibroblast-like cells isolated by collagenase digestion of epididymal and perirenal adipose tissue from male rats weighing 70-200 g. Adipose conversion as measured by lipid accumulation and increase in glycerophosphate dehydrogenase (GPDH) activity during differentiation strongly depends on the density at which cells are inoculated and starts only when cells are confluent and when physiological amounts of corticosterone and insulin are added. beta-Estradiol, testosterone, thyroxine, triiodothyronine, and growth hormone do not affect the differentiation process. Methylisobutylxanthine added during the first 2 days after confluence, added with insulin and corticosterone, potentiates the effect of insulin on GPDH activity and accelerates triglyceride accumulation. The effect of methyl-isobutylxanthine seems to be mediated by increased cyclic AMP concentrations, inasmuch as it may be replaced by forskolin.
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PMID:Hormonal regulation of the differentiation of rat adipocyte precursor cells in primary culture. 244 Sep 70

Due to the central role the acrosomal region plays in sperm-egg interactions, monoclonal antibodies (mAbs) were used to identify components of this domain in mouse sperm. Several sperm proteins that localize specifically to the anterior acrosomal region are described here in terms of electrophoretic mobility, susceptibility to proteolytic degradation, and post-translational modification during epididymal transit. Six different mAbs were used, each recognizing a distinctive antigen (Ag) or set of Ags in cauda epididymal mouse sperm: a doublet of 185/200 Kd (M42 mAb); 150-160 Kd (M5 mAb); 105 Kd (W71 mAb); 21, 35, and 60 Kd (M41 mAb); 27 and 33 Kd (W33 mAb); and 57 and 86 Kd (W108 mAb). Previously reported work implicates two of these, M42 Ag and M5 Ag, as participants in sperm-zona interaction (Saling and Lakoski: Biol Reprod 33:527-536, 1985; Saling: Dev Biol 117:511-519, 1986; and Lakoski et al.: Biol Reprod 38:221-233, 1988). Recognition of some (M42, M5, W108), but not all (W33), of the Ags by their corresponding mAbs was affected by sperm incubation with proteases (trypsin or collagenase). Evidence of post-translational modification during epididymal maturation was suggested by altered electrophoretic mobility of several of the Ags (M42, M5, W33, and W108) accompanying sperm transit from proximal to distal epididymis. Retention of sperm within the caput epididymis prevented structural alterations for the four proteins examined, indicating that spatial rather than temporal factors are critical for Ag modification in maturing mouse sperm.
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PMID:Proteins of the acrosomal region in mouse sperm: immunological probes reveal post-testicular modifications. 254 83

Epithelial cells of the rat's epididymal caput were cultivated according to own modification of the Kierszenbaum's method [1981]. The said modification consisted in developing primary cultures of the epithelial cells in the epididymal duct by making use of small tubular segments instead of deisolated cells of the whole epididymal duct wall. Such small segments of the tubules were procured by resorting to mechanical isolation and a 4-grade enzymatic isolation with trypsin and collagenase, whereupon the produced suspension of cells and tubules was filtered through a grid, the meshes of which being 40 X 50 microns in diameter. The cultures were made up exclusively of the tubular segments that had remained on the grid. The utilized technique of isolation gets rid of tubules from the external layer of muscle cells and fibroblasts as well as spermatozoa still prior to the inception of the culture, and provides the possibility to obtain a pure population of epithelial cells. The latter cells have the capacity to migrate from tubular fragments, and to form monolayer cultures. In the conducted cultures the epithelial cells commence secreting PAS-positive substance which was evidenced by means of histochemical and microscope-electron examinations.
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PMID:Modified procedure for isolation of epithelial cells of rat epididymal caput. 280 90

Intrapancreatic activation of proteases is believed to play a major role in the pathogenesis of acute necrotizing pancreatitis. Several authors have questioned, however, the central role of trypsin in autodigestion of the pancreas. To clarify the direct effects of pancreatic enzymes and other related factors on acinar cells, we used the model of isolated pancreatic acini. Acini were prepared from male Wistar rats by collagenase digestion. Protein synthesis was measured by incubation of acini with [35S]methionine. Acini were resuspended thereafter in fresh buffer and further incubated for 30-90 min under various conditions [e.g., with pancreatic homogenates, ascites (from rats with pancreatitis induced by sodium taurocholate), pure pancreatic enzymes, and other factors]. The percentage of release of newly synthesized proteins into the culture medium was regarded as a biochemical parameter of cellular integrity. A morphologic score of cellular integrity was obtained via light microscopic evaluation of acini at the end of the various incubations by measuring the degree of cell lysis, loss of cell granules, ballooning, formation of vacuoles, and karyopyknosis. When normal [35S]methionine-labeled pancreatic acini were incubated with various factors, the percentage of release of labeled proteins into the medium was as follows: incubation with HEPES/Ringer's buffer, 1.8%; hemorrhagic pancreatic ascites, 3.8%; pancreatic homogenates, 2.0%; lipase, 1.8%; phospholipase A2, 3.0%; phospholipase A2 + lecithin, 3.2%; trypsin, 2.5%; 5% olive oil, 1.8%; ascites + olive oil, 78.3%; ascites + homogenized epididymal fat, 79.9%; lipase + olive oil, 32.0%; pancreatic homogenates + olive oil, 28.0%; diolein, 2.65%; and oleic acid, 62.9%. The cellular release of radiolabeled proteins showed an inverse correlation with cellular integrity as shown by light microscopy. We postulate that interstitial release of degradation products from triglycerides by lipase causes cellular disruption. Whereas phospholipase A2 and proteases do not seem to be very harmful in the early phases of cellular damage, lipase may play a major role in acute necrotizing pancreatitis.
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PMID:Role of pancreatic enzymes and their substrates in autodigestion of the pancreas. In vitro studies with isolated rat pancreatic acini. 291 45

Growth hormone (GH) binding and the effect of GH and insulin on glucose metabolism in rat adipocytes were studied at various time periods following hypophysectomy. Male rats were hypophysectomized at 33-34 days of age. After 6 h, 20 h or 3, 7 and 14 days adipocytes were prepared from epididymal fat pads by mild collagenase digestion (0.5 mg X ml-1, 60 min, 37 degrees C). Glucose metabolism was studied by determining the production of CO2 from [14C]glucose and the incorporation of [14C]glucose into lipids. GH binding was measured in cell aliquots using [125I]hGH. No difference in GH binding to adipocytes was observed between control rats and rats hypophysectomized or sham-operated 6 h earlier. GH binding was significantly decreased 20 h after hypophysectomy and declined further with time after hypophysectomy. Adipose tissue from normal rats is usually refractory to the insulin-like effect of GH. Adipocytes isolated from normal rats were, however, usually responsive to GH immediately after cell isolation, suggesting that refractoriness to the insulin-like effect of GH was lost during the time required for the preparation of adipocytes. The magnitude of the response to GH in adipocytes progressively declined with time after hypophysectomy. The decreased responsiveness to GH with time after hypophysectomy parallelled the decrease in GH binding. The results suggest that the pituitary, directly or indirectly, is necessary for the maintenance of GH binding sites in adipose tissue and that these binding sites are related to the insulin-like effect of GH.
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PMID:Changes in growth hormone binding and metabolic effects of growth hormone in rat adipocytes following hypophysectomy. 299 Jan 66

To facilitate investigations on very small fat cell (VSFC) populations in adipose tissue, an alternate method of preparing fat tissue samples was explored. The osmium tetroxide-8M urea method, modified by addition of a 95% ethanol step in tissue processing, centrifugation between steps, and final resuspension in 55% glycerol in 0.01% Triton-saline, was compared with the collagenase method for determination of VSFC populations in Fischer 344 epididymal and Sprague-Dawley retroperitoneal adipose depots. For each method and in both depots, the average histogram of 300 adipocyte diameters, measured by microscopy, was bimodal with the nadir between 30 and 40 micron diameter. The average histogram of fat cells less than 35 micron in diameter showed a separate population of VSFC existed in each depot. The modified osmium-urea method gave better results and was easier to perform than the collagenase method. It has confirmed our earlier results and raises anew questions concerning a role for the natural existence of a VSFC population in the adipose depot.
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PMID:Very small fat cell populations determined by a modified osmium tetroxide-urea method. 299 Feb 29

The isolation and culture of ciliated and nonciliated cells from rat ductuli efferentes is described. Fragments of epithelium obtained after two collagenase digestions attached to plastic and to extracellular matrix and could be maintained in culture for at least 2 weeks. Ciliary beating in cells grown on epididymal extracellular matrix-coated plastic could be observed for up to 7 days in culture. Although cells maintained on this substrate retained organelles characteristic of cells in vivo, they assumed a flattened, squamous appearance. In contrast, cells growing on the surface of permeable supports impregnated with extracellular matrix were polarized and exhibited a cuboidal/columnar appearance. Androgen binding protein conjugated to colloidal gold was taken up by these cells via coated pits and was found sequentially in uncoated endosomes, multivesicular bodies and lysosomes.
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PMID:Culture of ciliated and nonciliated cells from rat ductuli efferentes. 299 98

Adult male rats were subjected to overfeeding with a high-fat, high-sugar diet for 3 and 7 days resulting in a moderate expansion of adipose tissue depots by an increase in fat-cell size. Seventeen hours and 7 days after injection of a pulse of labelled thymidine, specific activity of DNA was examined in different cellular fractions obtained from the epididymal and perirenal adipose tissues after collagenase liberation and separation procedures. A slow increase of formation of new adipocytes occurred after 3 and 7 days of overfeeding, most pronounced in cells from perirenal adipose tissue. Capillary endothelium and cells in the stromal fraction showed a rapid synthesis and turn-over. Overfeeding induced an increased formation of new capillary endothelial cells after 7 days of overfeeding, again most pronounced in perirenal cells. It was concluded that new fat cells are formed at a slow rate early during overfeeding. Capillary endothelium in adipose tissue has a high rate of turnover, and its synthesis is increased further by overfeeding. New adipocytes precede, and possibly stimulate, the formation of new capillaries. Formation of new cells in the remaining stromal-vascular cells is probably occurring at different rates among different types of cells.
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PMID:Increased DNA synthesis in adipocytes and capillary endothelium in rat adipose tissue during overfeeding. 311 64

Sperm maturation and storage occur in a unique milieu created in large part by the epididymal epithelium. To learn more about the interaction of the epididymal epithelial cell with both luminal and systemic environments, we now report on the preparation and characterization of epididymal epithelial cell plasma membranes. A preparation enriched for epididymal epithelial cell plasma membranes was isolated from collagenase-digested epididymal tubule fragments by hand-Dounce homogenization, differential centrifugation, and sucrose gradient centrifugation. The final membrane fraction was enriched 11-fold for the plasma membrane marker 5'-nucleotidase; 2.6-fold for the lysosomal marker acid phosphatase, and 3-fold for the Golgi marker thiamine pyrophosphatase. No enrichment was observed for mitochondrial or endoplasmic reticulum enzyme markers. Specific and saturable transferrin-binding activity was also detected in the final preparation. Electron microscopy revealed the presence of vesicles and sheets of membranes as well as an occasional Golgi apparatus. The plasma membrane fraction was used to generate monoclonal antibodies. Of 102 wells exhibiting growth, 12 were positive by immunofluorescent staining of frozen sections. Ten of these recognized determinants in epithelial cells, and 2 stained peritubular smooth muscle cells. Most of the epithelial cell-specific antibodies stained brush border alone or in combination with the basolateral plasma membrane. Three antibodies stained the Golgi apparatus. Most antibodies were specific for particular epididymal regions, 3 also recognized determinants in the kidney, and 1 stained residual bodies in the testis.
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PMID:Isolation and characterization of epididymal epithelial cell plasma membranes. 336 69


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