摘要:

AbstractEpithelial cells in the prostate of the castrated or hypophysectomized dog were studied by thin‐section and freeze‐fracture electron microscopy to determine in vivo responses to estradiol‐17β 17‐cyclopentylpropionate (ECP) and testosterone cyclopentylpropionate (TCP). Particular attention was given to changes in specific organelles and intercellular junctions that might reflect hormone action. The few secretory granules that remain in the regressed epithelium (vestigial granules) serve as markers of prior androgen responsiveness. Pharmacologic doses of ECP caused regressed glandular cells to acquire a novel phenotype. Characteristic features of these estrogen‐modified glandular (EMG) cells are newly formed secretory granules and tonofilament bundles that coexist with vestigial granules, thus demonstrating bipotentiality of response. Glandular cell‐tight junctions appear unaltered by the endocrine manipulations. Although EMG cells have squamous cell features, tight junctions remain intact. Desmosomes in the canine prostate are dimorphic and are classified 70F and 100F according to the width of the filaments that converge on the dense plaques. In intact dogs, 100F desmosomes are associated with basal‐reserve cells, whereas only the 70F variety is found between glandular cells. TCP treatment does not alter this distribution. Following ECP administration, both 70F and 100F desmosomes are present between EMG cells. The coexistence of newly formed secretory granules and tonofilaments of 100F desmosomes in the same EMG cell represents estrogen‐induced bidirectional differentiation. Our findings indicate that androgens and estrogens are individually capable of controlling the expression of secretory granules and desmosomes. In intact animals, male and female sex hormones may act in concert to direct epithelial cell differentiation

ISSN:0003-276X    

DOI:10.1002/ar.1091970202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe terminal buds of theCorydoras paleatuswere observed with the electron microscope. Almost all the cells constituting the buds can be classified into two distinct cell types, supporting and receptor cells. In addition, a few cells designated as basal cells exist in the bottom of the buds and appear to be an immature form of each distinct cell type in the course of cell renewal.The receptor cells are characterized by the presence of tubules extending from the apical process. By the application of lanthanum nitrate as an extracellular marker, we demonstrated that the tubular system is in continuity with the extracellular space.The data suggest that the tubular system represents an amplification of the apical cell surface as a particular site of chemoreceptive activities, although we do not rule out a role for active absorptions of ions in a very hypotonic environment.

ISSN:0003-276X    

DOI:10.1002/ar.1091970203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractAn ultrastructural study of spermiogenesis was carried out in adult hypophysectomized rams supplemented with testosterone at a dose which induced a normal or excessive (1 to 3) concentration of the steroid within the rete testis fluid (Monet‐Kuntz et al., '76). Most of the spermatids from 15‐ or 20‐day treated animals displayed a normal nuclear appearance but possessed acrosomes with morphological abnormalities. The process of acrosome formation as well as its binding to the nucleus was severely impaired in young spermatids, whereas only morphological changes of the acrosomes were seen in old spermatids. The suggestion is made that acrosome development is under the control of endocrine‐dependent cellular events occurring before the beginning of spermiogenesis, possibly via Sertoli cell/germ cell interactions. The spermatids from hypophysectomized rams supplemented with testosterone for 40 days were normal in appearance but reduced in number. The Sertoli cell ultrastructure differed for the two durations of tr

ISSN:0003-276X    

DOI:10.1002/ar.1091970204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThyrotropin‐releasing hormone (TRH) stimulates prolactin production in cultured GH3rat anterior pituitary tumor cells. For correlation of cell‐by‐cell prolactin distribution and intracellular hormone concentration, GH3cells were grown to plateau‐phase density on glass coverslips in plastic dishes. Acetone‐fixed, cell‐bearing coverslips were stained for prolactin by an immunoglobulin‐peroxidase bridge technique (Mason et al., '69); cells on the plastic dishes were assayed for prolactin (microcomplement fixation immunoassay, Tashjian, '73) and protein content. Intracellular prolactin, unaffected quantitatively by acetone fixation and choice of substratum, was localized immunocytochemically by a granular brown precipitate, abolished if anti‐prolactin serum was preabsorbed with rat prolactin or omitted from the protocol. Intracellular prolactin was maximized with colchicine (5.0 × 10−6M; final 3 hr of incubation) in control and TRH‐treated (10 ng/ml; 48 hr) GH3cell cultures. A total of 8,500 cells were classified by light microscopy as unstained, heavily (H) or moderately (M) stained for prolactin. In controls, 35% of cells were prolactin‐positive: 6% H and 29% M. After TRH, 45% were positive: 7% H and 38% M. Although prolactin‐positive cells were unevenly distributed, comprising 25% to 46% of cells in individual microscopic fields in controls, TRH increased the proportion of M cells in all areas. TRH treatment raised prolactin levels to 450% of control, but mathematical analysis attributed less than 30% of the increase to new prolactin‐positive cells. We conclude that TRH acts on GH3cultures principally by raising the mean hormone content of individual positive cells rather than by increasing the proportion of cells committ

ISSN:0003-276X    

DOI:10.1002/ar.1091970205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe preceeding report (Hoyt and Tashjian, '80) correlates immunocytochemical localizations and mean prolactin concentrations in GH3monolayers maximally stimulated with TRH; the present does so over the duration of TRH treatment. Low density seeding produced numerous discrete GH3cell colonies. Cultures were harvested ½, 4, 12, 24, 72, and 144 hr after administration of TRH (50 ng/ml) or saline (control). All cells (42,658 total) in at least 10 microscopic fields/monolayer, 1 cell colony/field, were classed as unstained, heavily (H), moderately (M), or weakly (W) stained for prolactin. In controls, colonies contained 51‐91 prolactin‐positive cells/100 of population. Colonies with few positive cells had many more W than M cells, and the reverse was true in those with many positive cells. In all colonies, the effect of TRH was biphasic. Initial (0‐4 hr) release of prolactin was overlapped, beginning at 3‐4 hr, by a progressive increase of intracellular hormone. After 144 hr, the prolactin content of treated cultures had increased to 190% of control, and prolactin‐positive cells were more numerous (114% of control). These increases were lower than those reported in the preceeding paper after 48 hr of TRH treatment, when intracellular prolactin equalled 450% of control and positive cells equalled 129% of control. These inconsistencies reflect differences in the control level of prolactin production rather than in the absolute effects of TRH, which were virtually identical in the successive experiments. We conclude that: (1) TRH acts to alter hormone production in cells already making prolactin; (2) TRH increases somewhat the number of prolactin‐containing cells; (3) the relative contribution of such “new” cells to increased hormone output depends on the basal level of prolactin production, which differs among individual GH3cell colonies and varies over time in culture. This diversity does not diminish the usefulness of GH3cells as biochemical models of hormone biosynthesis. It does hinder their valid morphological evaluation, which apparently must be controlled as carefully as biochemical experiments and should include immunocytochemical localizations, at least for the

ISSN:0003-276X    

DOI:10.1002/ar.1091970206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe cellular and subcellular localization of albumin in hepatocytes of adult male rats was established with immunofluorescence and immunoperoxidase techniques. Livers were fixed while either filled or devoid of blood. In some rats, prior treatment with cycloheximide was used to deplete the albumin content of hepatocytes. Immunofluorescence of blood‐free livers from untreated rats showed that all hepatocytes contained albumin. However, using the peroxidase method, the amount of immunoprecipitate in cisternae of the rough endoplasmic reticulum was so slight that specific localization of albumin was impossible. Yet in all cases, a positive reaction for the presence of albumin was seen on ribosomes attached to the endoplasmic reticulum. In contrast, immunofluorescence of blood‐filled livers from untreated rats and those previously injected with cycloheximide showed that only a few scattered hepatocytes were positive for albumin. In these cases, subcellular localization of albumin was obvious because the immunoprecipitate was found in heavy concentration, but only in the cytosol compartm

ISSN:0003-276X    

DOI:10.1002/ar.1091970207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe cellular immunolocalization of albumin in rat liver has been studied as a function of various physiological and physical conditions. Our observations show that the prime requisite for accurate immunolocalization of albumin and other hepatic‐based proteins is the complete removal of blood and especially plasma from sinusoids and the perisinusoidal space of Disse prior to fixation.Fixation of blood‐filled liver specimens results in the antifactual entrance of plasma constituents into hepatocytes. When the fixative used is formaldehyde, the artifactual uptake occurs primarily into hepatocytes that have a high glycogen content. Fixation of blood‐filled liver with acetic acid‐ethanol causes a massive influx of plasma into all hepatocytes. On the contrary, with blood‐free liver, varying the type of fixative consistently demonstrates that all hepatocytes normally contain albumin, transferrin, and fibrinogen simultaneously.Increasing the time between cessation of blood flow and outright fixation by either withholding the fixative or by impeding its diffusion through the specimen causes a progressive loss of antigenicity of albumin. The same result ensues when specimens remain in contact with the fixative for an exte

ISSN:0003-276X    

DOI:10.1002/ar.1091970208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractStudies of Sertoli cell structure, maturation, and function have been aided by the use of in vitro systems. Although numerous papers have appeared that utilize the Sertoli cell culture model, few papers have dealt with the characterization of these cells under various culture environments. Recently, it has been reported that the addition of serum to the culture medium prevents induction of long cytoplasmic appendages in cultured Sertoli cells that have been treated with FSH, TSH, or c‐AMP. The purpose of this investigation was to determine which serum components, obtained by gel filtration, are capable of inhibiting the morphological response induced by FSH, TSH, or c‐AMP. Sertoli cell‐enriched cultures were prepared using collagenase and trypsin digestion, each followed by gravity sedimentation. Untreated cells grown on plastic or glass substrates assumed an epithelioid appearance after several days. Cells treated with FSH, TSH, or c‐AMP formed long cytoplasmic appendages after 1‐2 days. This response was prevented or reversed by the addition of fetal calf serum (10%), crystallized bovine serum albumin (0.25%‐2%), or purified albumin obtained by gel filtration of whole serum (0.25%). It was also found that fractions that elute between the void volume and the initial albumin fractions (molecular weights of approximately 50,000 and greater) mimic the hormone‐induced response after only 10‐12 hours. The results of this investigation indicate that albumin is the primary serum component responsible for inhibiting morphological alterations induced by FSH, TSH, and c‐AMP. Furthermore, it is apparent that the production of long filamentous cytoplasmic appendages in Sertoli cells can be induced by a wide vari

ISSN:0003-276X    

DOI:10.1002/ar.1091970209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe permeability of the epithelium lining serous cysts of the guinea pig ovary was examined using lanthanum and horseradish peroxidase (HRP). Both lanthanum and HRP introduced at the luminal surface of the cyst penetrated to the basal region filling caveolae in both lateral and basal cell surfaces. Within three minutes of vascular infusion of HRP, the tracer was detected between epithelial cells and in caveolae on their lateral and basal surfaces but not associated with intracellular organelles. There was no change in the intracellular distribution of HRP after ten minutes. It was concluded that the epithelium was permeable to the tracers within this time period but that pinocytosis and transport of these tracers through the epithelial cell were not demonstrated.

ISSN:0003-276X    

DOI:10.1002/ar.1091970210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY

摘要:

AbstractThe permeabilities of the parietal yolk sac placenta and the preplacental region of the hamster conceptus during early postimplantation (day 8) were compared by means of electron microscopy and a macromolecular protein tracer, horseradish peroxidase (HRP). HRP was administered by injection into the maternal venous system; samples of the two placental tissues were obtained for examination at intervals between 4 minutes and 1 hour later. The three layers of the parietal yolk sac wall (from outer to inner: capsular trophoblast, Reichert's membrane, parietal endoderm) appeared to provide little impediment to the passage of HRP from perivitelline maternal blood spaces to the yolk sac cavity. HRP passed through the outer trophoblast layer, both by way of intracellular fenestrae (60‐200 nm diameter) and narrower intercellular channels, and completely permeated the meshwork of Reichert's membrane within minutes after injection. The inner parietal endoderm cell layer was widely discontinuous and clearly presented no barrier to HRP movement. HRP reaching the yolk sac cavity was avidly endocytosed by the visceral yolk sac epithelium. In contrast to the parietal yolk sac, the preplacental region of the conceptus was impermeable to HRP. Zonular occluding junctions located between contiguous cells of the chorionic ectoderm layer of the preplacenta were the obvious barrier to the HRP molecules. These results suggest that in this rodent species, during the early postimplantation period of gestation, the parietal yolk sac placenta potentially plays a more important role in the maternal‐embryonic transfer of macromolecular substances than does the preplace

ISSN:0003-276X    

DOI:10.1002/ar.1091970211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1980

数据来源: WILEY