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T Barka

Publications and source records attributed to T Barka.

At least 55 records · Page 3Linked to original sources
PubMed1981

Epidermal growth factor and renin in mouse submandibular glands.

Epon sections of the submandibular gland of SWF/J male mouse were stained immunocytochemically for epidermal growth factor (EGF) and renin. Most cells of the granular convoluted tubules (GCT) contained both EGF and renin. However, examinations of adjacent semithin or thin sections stained for EGF and renin, respectively, revealed a small population of GCT cells that contained EGF but no renin. Within a cell all secretory granules contained both EGF and renin. The renin-negative/EGF-positive cells may represent a subpopulation of tubular cells that do not express, or carry, the renin gene.

Animals↗
PubMed1981

Immunocytochemical investigations on the submandibular glands of developing and adult mice using a specific antiserum on protease A.

The submandibular glands of developing and adult mice were studied immunocytochemically by the unlabeled antibody peroxidase-antiperoxidase and the colloidal gold-protein A methods, using an antiserum to a highly purified esteroprotease (protease A, EC 3.4.4) of mouse submandibular gland origin. A thin subluminal rim of immunoreactivity, seen in striated duct cells throughout development, persisted in adulthood. From 15 days of age onwards, striated duct cells with diffuse cytoplasmic staining also occurred; such cells increased in number with age. A clear sexual dimorphism of the submandibular gland was first discernable by 25 days of age, when the developing granular convoluted tubule (GCT) cells of males were slightly larger than those of females; this size difference became more pronounced at later ages, resulting in a distinct dimorphism by 50 days of age. In adults, the principal sites of immunoreactivity were the GCTs, whose component cells stained with different intensities. Electron microscopic immunocytochemical techniques revealed that deposits of oxidized diaminobenzidine or particles of celloidal gold were restricted to the secretion granules of GCT cells; all other organelles were unstained. Acinar and intercalcated duct cells were negative.

Animals↗
PubMed1981

Hormonal regulation of epidermal growth factor and protease in the submandibular gland of the adult mouse.

The structure of the granular convoluted tubules of the mouse submandibular gland is influenced by androgens, adrenal steroids, and thyroid hormones. We wished to investigate the effects of variations in hormonal status on the quantitative and qualitative distribution of two secretory products of these tubules, epidermal growth factor (EGF) and protease. The effects of the thyroid and adrenal glands on EGF content and protease activity of the submandibular glands of adult female mice were studied by RIAs (EGF), enzyme assays (protease), and immunocytochemical methods. In animals rendered chronically hypothyroid by propylthiouracil (4 months) or in animals which were adrenalectomized and ovariectomized (3 weeks), protease activity and EGF levels were reduced by 81-97%. The administration of testosterone induced these polypeptides even in hypothyroid animals. Daily administration of L-T4 (T4; 1 micrograms/g BW) for 7 days increased EGF and protease activity 3.6-fold in intact mice and reversed the effect of hypothyroidism. EGF and protease were also induced by T4 in adrenalectomized and ovariectomized mice, although to a lesser degree than in intact animals. Immunocytochemical stainings of submandibular glands indicated that the number of granular convoluted tubule cells immunoreactive for EGF correlated with the levels of EGF determined by RIAs. With respect to immunostaining for protease, such a correlation was not observed. The data indicate multihormonal regulation of EGF and protease in the mouse submandibular gland.

Adrenal Glands↗
PubMed1980

Immunocytochemical localization of nerve growth factor, submandibular glands of Tfm/Y mice.

The submandibular glands of mice with testicular feminization (Tfm/Y) and their normal adult male littermates (Ta/Y) were studied by immunocytochemical techniques for the demonstration of epidermal growth factor (EGF), nerve growth factor (NGF), renin and protease A. In the glands of both the affected and normal males, these polypeptides were restricted to cells of the granular convoluted tubules (GCT), with the exception of protease A, which was also found in small amounts in striated duct cells. Compared to those of Ta/Y males, GCTs were narrower in the glands of Tfm/Y mice and contained a markedly reduced number of cells immunoreactive for EGF, NGF and renin. However, the number of GCT cells that stained for protease A in the glands of Tfm/Y males was not as drastically decreased.

Androgen-Insensitivity Syndrome↗
PubMed1980

Immunocytochemical localization of renin in kidneys and submandibular glands of SWR/J and C57BL/6J mice.

By using antibodies against highly purified submandibular gland renin, renin was localized immunocytochemically at the light and electron microscopic level in the submandibular glands and kidneys of adult male SWR/J and C57BL/6J mice. In accord with the data of Wilson et al. (Proc Natl Acad Sci USA 75:1185, 1977), renin was demonstrable only in the submandibular glands of SWR/J mice (high strain), where it was confined to the secretory granules of the granular convoluted tubules. In the kidneys of both strains, renin was confined to epithelioid cells of the juxtaglomerular apparatus. Electron microscopically immunostaining was restricted to the granules of the juxtaglomerular epitheliod cells. Morphometric analyses suggested that the kidney of the C57BL/6J mice contained more immunoreactive complexes per unit volume of cortex than SWR/J mice kidney. The data indicate that submandibular gland renin cross-reacts with kidney renin, but that genetic controls of these polypeptides in the two organs are independent.

Animals↗
PubMed1980

Biologically active polypeptides in submandibular glands.

Since the discovery of kallikreins in the submandibular glands in 1963 by Werle and Roden, a great number of biologically active polypeptides has been purified from, or claimed to be present in, the submandibular of the mouse and of other species. In this review, available data on the occurrence, chemical properties, localization, hormonal control, synthesis, secretion, and possible physiologic roles of 25 biologically active factors in mouse submandibular gland are analyzed. In general, these factors are androgen dependent, but not affected by the sex genotype, and are localized in the granular convoluted tubule cells in the gland. They are secreted into the saliva, but are also found in the circulation. Their physiologic roles are largely unknown.

Angiotensins↗
PubMed1980

Epidermal growth factor, renin, and peptidase in cultured tumor cells of submandibular gland origin.

Dimethylbenz[a]anthracene was injected into the submandibular glands of male Swiss-Webster mice. From tumors obtained, three cell lines were established. Immunocytochemical stainings revealed epidermal growth factor, renin, and peptidase in a significant portion of cultured tumor cells. In addition, the presence of epidermal growth factor was demonstrated by radioimmunoassays. Since epidermal growth factor, renin, and peptidase are localized in the granular convoluted tubules in mouse submandibular gland, the data suggest that the granular convoluted tubule cells are the targets of chemical carcinogens.

Animals↗
PubMed1979

Epidermal growth factor-like material in rat submandibular gland.

By using an antiserum specific for mouse epidermal growth factor (EGF), only the granular convoluted tubule (GCT) cells revealed immunochemical staining in rat submandibular glands. There was no regular sexual difference in the frequency or size of immunoreactive cells. Extracts of gland contained an antigen which showed a complete cross-reactivity with mouse EGF in radioimmunoassays. The relative amounts of EGF, determined by a heterologous radioimmunoassay, were not significantly different in the glands of rats of the two sexes. Administration of testosterone caused an increase, in both sexes, in the number of GCT cells stained for EGF and in the amount of EGF in the gland. There was no significant sexual differeence in these two parameters after androgen treatment.

Animals↗
PubMed1978

Beta-adrenergic receptors and adenylate cyclase in hypertrophic and hyperplastic rat salivary glands.

Isoproterenol induces both the secretion of protein and the stimulation of DNA synthesis and growth in rat salivary glands. The specific binding of the labelled beta-adrenergic antagonist [3H]dihydroalprenolol has been used to measure the number of beta-adrenergic receptors in rat parotid glands during isoproterenol-induced growth. Isoproterenol-enlarged glands display no change in the specific binding capacity per gland for [3H]-dihydroalprenolol compared with normal tissue. Catecholamine sensitive adenylate cyclase activity varies independently of the number of specific [3H]dihydroalprenolol binding sites during isoproterenol-induced growth. Previously-described di-ferences in optimal isoproterenol doses which produce protein secretion and stimulation of DNA synthesis may reflect different responses to various rates of receptor occupancy, or may be due to the presence of more than one type of beta-adrenergic receptor.

Adenylyl Cyclases↗
PubMed1978

Stimulation of secretion of epidermal growth factor and amylase of cyclocytidine.

Radioimmunoassays and immunocytochemical techniques were used to assess the effect of cyclocytidine, an antitumor agent, on the level and localization of Epidermal Growth Factor (EGF) in the submandibular gland of the male mouse. A single intraperitoneal injection of 150 mg/kg of cyclocytidine caused, within 6 h, a degranulation of the granular convoluted tubules (GCT) cells and reduced the concentration of immunoreactive EGF in gland extracts by more than 90%. This effect was largely abolished by the administration of dibenzyline but not by propranolol, indicating that the secretory effect of the drug on the GCT cells is mediated by alpha-adrenergic receptors. By immunocytochemical staining revealed the same trends in changes in EGF concentration as the radioimmunoassays. However, even at the peak of the cyclocytidine effect there were cells which retained their secretory granules and apparently their EGF complement. In addition, there was a lobular variation in the secretory response. Cyclocytidine caused a transiet increase in the blood level of EGF. Furthermore, it stimulated amylase secretion from the gland, which also involved alpha-adrenergic receptors. Cyclocytidine will be useful in future analyses of the release of various biologically active substances from the GCT cells of the mouse submandibular gland.

Adrenergic alpha-Antagonists↗
PubMed1978

Immunocytochemical localization of epidermal growth factor during the postnatal development of the submandibular gland of the mouse.

The time of appearance and the pattern of localization of epidermal growth factor (EGF) in submandibular glands of mice was studied during postnatal development immunocytochemically. EGF was first detectable in the granular convoluted tubule (GCT) cells in the glands of males at 20 days of age and of females at 30 days of age. Development of GCT cells containing EGF was rapid in males, approaching adult conditions by 45 days of age. In females EGF- containing GCTs developed more slowly and irregularly, and did not reach adult status by 45 days of age. It is concluded that EGF is restricted during postnatal development to the GCT cells, and that these cells and the distribution of EGF are represented dimorphically from their first appearance in the submandibular glands of both sexes.

Age Factors↗
PubMed1978

Immunocytochemical localization of renin in the submandibular gland of the mouse during postnatal development.

The localization of renin in the developing mouse submandibular gland was studied immunocytochemically using the unlabelled antibody-enzyme method of Sternberger ('74). Bouin-fixed submandibular glands of mice of both sexes were examined at 5-day-intervals from birth (day 0) to 50 days of age. At all stages studied, only granular convoluted tubule (GCT) cells stained immunocytochemically for renin; such cells were first seen in glands of 30-day-old males and of 30-day-old females. The size and number of renin-containing GCT cells increased rapidly in males, attaining adult status by 50 days of age. In females, differentiation of GCT cells immunoreactive for renin was slower and less regular than in males, and at 50 days of age the GCT segment had not yet reached adult conditions with respect to the distribution of renin. Renin appears in GCT cells at later ages than other GCT cell products (e.g., EGF and amylase), suggesting the existence of independent developmental control for the expression of various biologically active substances in the GCTs.

Aging↗
PubMed1978

Immunocytochemical localization of renin in the submandibular gland of the mouse.

Renin was localized in the submandibular gland of the adult mouse at light and electron microscopic levels by the unlabeled antibody enzyme method of Sternberger. At the light microscopic level, renin was confined to the granular convoluted tubule (GCT) segment of the gland with considerable variation among GCT cells in intensity of staining. Some GCT cells failed to stain for renin. The pattern of staining was the same in the gland of male and female mice, but in the glands of females GCT segments were smaller and less numerous. At the electron microscopic level, staining for renin was also confined to the GCT cells, and was localized exclusively to the secretory granules. The intensity of staining of the secretory granules within a given GCT cell varied; some cells contained only minimally reactive or negative secretory granules. All other organelles within the GCT cell, except condensing vacuoles, failed to stain.

Animals↗
PubMed1977

Secretory behaviour of hypertrophic and hyperplastic salivary gland.

The enzyme content and the secretory behaviour of normal rat salivary glands were compared with these properties in glands made hypertrophic and hyperplastic by the chronic administration of isoproterenol. The enlarged glands displayed reductions in the concentrations of ribonuclease, deoxyribonuclease and amylase. The secretory behaviour in vivo was similar for all enzymes in both types of glands, but the enlarged glands secreted a lower percentage of their content in vitro. The reduction in amylase activity was shown by immunological techniques to be due to a reduction in the number of enzyme molecules. The reduction in ribonuclease activity was not due to changes in the level of ribonuclease inhibitors.

Amylases↗
PubMed1977

Immunocytochemical localization of epidermal growth factor in mouse submandibular gland.

The cellular and subcellular localization of epidermal growth factor in the submandibular glands of male and female adult mice was established by immunoperoxidase techniques. In light microscopic preparations epidermal growth factor was found exclusively in the granular convoluted tubules of the gland. The intensity of staining for epidermal growth factor varied from cell to cell, and some cells apparently were negative. The pattern of staining was similar in the glands of male and female mice; however, the granular convoluted tubules are androgen-responsive, and thus more extensive and composed of larger cells in males. In thin sections epidermal growth factor was most heavily concentrated in the secretion granules of the granular convoluted tubule cells. Within a given cell there was variation in intensity of staining of individual secretion granules, with some granules appearing minimally reactive or negative. The only other cell component with deposits of reaction product was the ribosomes.

Animals↗
PubMed1977

The effect of neonatal sympathectomy on the response of the rat submandibular gland to isoproterenol.

The right superior cervical ganglion was removed from 1-day-old rat pups. For four consecutive days (22-26 days of age), the rats were injected twice daily with isoproterenol-HCl (IPR) at a dose of 2.0 mg/100 g.b.w. and killed on the 27th day of age. Control animals were injected with the solvent, 0.1% Na2S2O5, according to the same protocol. In both control and IPR-treated rats, fluorescence microscopic examination of glands prepared by the Falck-Hillarp method showed a total absence of adrenergic nerve fibers on the side of sympathectomy, and a normal innervation on the unoperated side, while light microscopic examination of Epon-embedded glands revealed no differences in structure between the noninnervated and intact glands. However, after IPR treatment the noninnervated glands consistently showed greater absolute and relative weight, and total DNA, RNA and protein than the corresponding intact gland from the same animal. It is suggested that this greater hyperplastic and hypertrophic response in the noninnervated gland represents a postjunctional supersensitivity of acinar cells to the beta agonistic action of IPR.

Animals↗
PubMed1976

The effects of 5-bromodeoxyuridine and isoproterenol on the postnatal differentiation of rat submandibular gland.

The effects of 5-bromodeoxyuridine (BrdU) on the postnatal differentiation of rat submandibular gland and on the isoproterenol-induced changes of differentiation were studied. The rats were injected with BrdU for three consecutive days, beginning at two days of age. The total dose of BrdU was 0.9 mg/g body weight. BrdU caused a severe retardation of growth up to 15 days of age. A rapid growth of the animals between 15 and 22 days indicated a recovery from the effect of BrdU. The growth of the submandibular gland was retarded similarly with a corresponding decrease in DNA, RNA and protein content. Incorporation of tritiated thymidine into the submandibular gland was not altered in the BrdU-treated animals at one and three days after the last injection of the analog. At days 15 and 22 the rate of thymidine incorporation was greater in the submandibular gland of BrdU-treated rats as compared to littermate controls. Isoproterenol stimulated thymidine incorporation into the submandibular glands of two-week-old rats. This stimulation was not observed in rats which received BrdU at age 7-9 days, prior to the administration of isoproterenol. Election microscopic observations, including a quantitative analysis of the frequency distribution of the various cell types in the terminal tubules and developing acini, indicated a retardation of acinar cell differentiation in the glands of BrdU-treated rats. In addition, there was an increase in the number and size of the secretory granules in the terminal tubule cells. BrdU treatment, however, caused no obvious pathologic alterations in the submandibular gland. Administration of isoproterenol for five days, beginning at five days of age, caused an apparent acceleration of the differentiation of acinar cells. In the glands of isoproterenol-treated rats the acinar cells were enlarged and were filled with homogeneous secretory granules. Pretreatment with BrdU partially inhibited the effects of isoproterenol on differentiation and hypertrophy of the submandibular gland. With the given dose of BrdU, approximately 5% of thymine was replaced by bromouracil in the DNA of the submandibular gland. Such a replacement would be consistent with a direct effect of BrdU on the cytodifferentiation in the submandibular gland. However, because of the severe retardation of growth of the BrdU-treated rats, indirect effects can not be excluded.

Animals↗