Immunocytochemistry of pituitary corticotroph cells in terrestrial turtle (Testudo mauritanica)]

The immunocytochemical and histochemical characters of the corticotroph cells of the Turtle adenohypophysis have been studied. These cells are localised in the rostral part of the gland and are revealed by Is anti ACTH (1-24) and (17-39). They are also colored with lead hematoxyline and PAS-Orange G. The corticotroph nature of these cells is confirmed by the study of their modifications after treatment with amphenone and ACTH. The Is anti ACTH also reveal most of the cells of the pars intermedia; while the Is anti beta-MSH reveals only these cells and some scatter cells of the pars distalis.     

APUD characteristics and immunocytochemistry of avian pituitary corticotrophs.

L-DOPA is taken up and decarboxylated by cells in the avian adenohypophysis, which are situated largely in the cephalic lobe. These APUD cells have been shown by sequential formaldehyde-induced and immunofluorescence to be corticotrophs and the relationship between the two procedures has been found to have a reciprocal quality.     

Immunocytochemical localization of neurons containing ACTH 17-39 in the rat brain]

Immunoreactive neurons and fibers were localized in the Rat brain by immunocytochemistry using an anti-ACTH 17-39 antiserum. Neither adrenalectomy nor water deprivation affected intensity of distribution of reaction of labelled neurons whereas colchicine increased labelling of hypothalamic perikarya. These results support the neuronal origin of cerebral ACTH.     

Cyto-immunochemical detection of gamma endorphin in swine adenohypophysis]

An immunserum was prepared from gamma endorphin and its specifity was checked by the indirect method. It was tested on hypophysis which were taken from Pigs since birth till 3 months old. The anterior lobe as well as the intermediate lobe have reacted. The same cells were positive in the anterior lobe and recognized the anti-ACTH, anti-beta MSH and anti-beta LPH immunserums. However, the reaction was more labile than with these last immunserums and it was varying with the delay of fixation after the death and the penetration in the gland by the fixator.     

Prevention of cisplatin-induced ototoxicity by the inhibition of gap junctional intercellular communication in auditory cells

Cis-diamminedichloroplatinum (cisplatin) is an effective chemotherapeutic drug for cancer therapy. However, most patients treated with cisplatin are at a high risk of ototoxicity, which causes severe hearing loss. Inspired by the “Good Samaritan effect” or “bystander effect” from gap junction coupling, we investigated the role of gap junctions in cisplatin-induced ototoxicity as a potential therapeutic method. We showed that connexin 43 (Cx43) was highly expressed in House Ear Institute-Organ of Corti 1 (HEI-OC1) cells, mediating cell–cell communication. The viability of HEI-OC1 cells was greatly decreased by cisplatin treatment, and cisplatin-treated HEI-OC1 cells showed lower Cx43 expression compared to that of untreated HEI-OC1 cells. In particular, high accumulation of Cx43 was observed around the nucleus of cisplatin-treated cells, whereas scattered punctuate expression of Cx43 was observed in the cytoplasm and membrane in normal cells, suggesting that cisplatin may interrupt the normal gap junction communication by inhibiting the trafficking of Cx43 to cell membranes in HEI-OC1 cells. Interestingly, we found that the inhibition of gap junction activity reduced cisplatin-induced apoptosis of auditory hair cells. Cx43 siRNA- or 18α-GA-treated HEI-OC1 cells showed higher cell viability compared to control HEI-OC1 cells during cisplatin treatment; this was also supported by fluorescence recovery after photobleaching studies. Inhibition of gap junction activity reduced recovery of calcein acetoxymethyl ester fluorescence compared to control cells. Additionally, analysis of the mechanisms involved demonstrated that highly activate extracellular signal-regulated kinase and protein kinase B, combined with inhibition of gap junctions may promote cell viability during cisplatin treatment.     

Electron microscope observation of "thyroidectomy cells" in the hypophyseal ventral lobe of a Chondrichthyan fish, the small spotted dogfish, Scyllium canicula Cuv.]

In the adenohypophysis of very young spotted dogfish, only one kind of granulated cells show strcutural changes following thyroidectomy: the small granule cells of the ventral lobe (granule diameter about 110 nm). These cells are similar to the thyrotrophs of other Vertebrates, and well distinct from the supposed gonadotrophs found in the same lobe.     

Immunofluorescence identification of cells with corticotropic and alpha-melanotropic activity in the hypophysis of the grass snake Natrix natrix L.]

The use of anti ACTH (17-39) and alpha-MSH allowed us to detect by immunofluorescence in the Pituitary gland of Grass Snake the site of elaboration of ACTH and alpha-MSH. Corticotropic cells are located in the rostral part of the Pars Distalis and in the Pars intermedia. Melanotropic cells occupy the whole part of the Pars intermedia.     

Cytoimmunological study of the corticotrophic and corticomelanotrophic cells in the adenohypophysis of Boops salpa L. (marine teleost) in different experimental conditions (variation of salinity and of background color)]

The cytoimmunological study of the adenohypophysis of Boops salpa (marine Teleost), in different experimental conditions confirmed that the MacConaill's hematoxyline-positive cells contain: 1. ACTH (Corticotrophic Hormone) in the pars distalis, 2. MSH (Melanocyte-Stimulating Hormone) and ACTH in the pars intermedia.     

Immunocytological identification of two cell types in the intermediate lobe of the hypophysis of salmonids: presence of ACTH and alpha-MSH]

The lead-haematoxylin positive cells (PbH+) of the rostral pars distalis react with antibodies anti-1-24 ACTH and anti-17-39 ACTH; the pars intermedia (PI) is composed of two cell categories, but only one is revealed with cyto-immunological techniques and contains ACTH and alpha-MSH in several Salmonid species.     

Immunohistochemical study of the pars intermediate of the mouse pituitary in different experimental conditions.

Alpha-MSH, beta-MSH and ACTH have been localized in the cells of hypophyseal intermediate lobe by fluorescence histoimmunological technics. Elaboration and excretion of these polypeptides are enhanced after dehydration or adrenalectomy. The most evident variations are seen with alpha-MSH and ACTH after dehydration, with beta-MSH after adrenalectomy.     

Histochemical and ultrastructural modifications of mice endometrium, vagina and pituitary following zeranol treatment

The histochemical and ultrastructural changes produced by zeranol treatment on the endometrium and the gonadotropic FSH cells of the adenohypophysis have been investigated in mice at the prepuberal and virginal stages. Modifications similar to those induced by estrogen treatment were observed. It is concluded that both estrogens and zeranol share the same activity on the tissues examined.     

Histochemical and ultrastructural modifications of mice endometrium,vagina and pituitary following zeranol treatment

Summary The histochemical and ultrastructural changes produced by zeranol treatment on the endometrium and the gonadotropic FSH cells of the adenohypophysis have been investigated in mice at the prepuberal and virginal stages. Modifications similar to those induced by estrogen treatment were observed. It is concluded that both estrogens and zeranol share the same activity on the tissues examined.     

Changes of profiles of neutrophil granulocytes induced with the administration of L-DOPA and prednisolone

Morphological changes of granulocytes following combined treatment with L-DOPA and prednisolone were elucidated at the electron microscopic level. Neutrophil granulocytes exhibited marked changes in their surface as evidenced by scanning electron microscope. It is suggested that neutrophil granulocytes are sensitive to some biogenic amines.     

Immunofluorescent localization of beta-lipotropin (beta-LPH) and beta-endorphins in normal and anencephalic human fetal pituitary gland]

The use of antibodies to alpha-(17-39) ACTH, beta-LPH, alpha- and beta-endorphins has enabled the detection of immunoreactive cells in human fetal pituitary glands as early as the eight week of gestation. The same cells reacted with the different antibodies. Immunoreactive cells were also observed in the pituitary of 6 human anencephalic fetuses.     

Changes of profiles of neutrophil granulocytes induced with the administration of L-DOPA and prednisolone

Summary Morphological changes of granulocytes following combined treatment with L-DOPA and prednisolone were elucidated at the electron microscopic level. Neutrophil granulcytes exhibited marked changes in their surface as evidenced by scanning electron microscope It is suggested that neutrophil granulocytes are sensitive to some biogenic amines.     

Changes in the level of ACTH in the fetal hypophysis. A study in the rat toward the end of gestation]

The isolated adrenal cell method for bioassay of ACTH was employed in order to determine the ACTH content of the hypophysis of the rat foetus, in late pregnancy. The ACTH concentration decreases between 17 days 8 h and 17 days 15 h, then it increases regularly until the term. This evolution is correlated with the change in the fluorescence intensity of the corticotrophs and with the modification of the adrenocortical activity.     

Demonstration of a tryptaminergic mechanism in the rat beta-cell.

Yellow 5-HT fluorescence has been histochemically demonstrated in rat pancreatic islet cells in animals injected with L-5-HTP with or without pretreatment with the monoaminoxidase inhibitor nialamide. This fluorescence was not observed after inhibition of the aromatic amino acid decarobxylase. The results strongly suggest the presence of a tryptaminergic mechanism in the rat islet cells.     

Interleukin-17 stimulates inducible nitric oxide synthase-dependent toxicity in mouse beta cells

The influence of the proinflammatory cytokine interleukin (IL)-17 on inducible nitric oxide (NO) synthase (iNOS)-mediated NO release was investigated in the mouse insulinoma cell line MIN6 and mouse pancreatic islets. IL-17 markedly augmented iNOS mRNA/protein expression and subsequent NO production induced in MIN6 cells or pancreatic islets by different combinations of interferon-γ, tumor necrosis factor-α, and IL-1β. The induction of iNOS by IL-17 was preceded by phosphorylation of p38 mitogen-activated protein kinase (MAPK), and inhibition of p38 MAPK activation completely abolished IL-17-stimulated NO release. IL-17 enhanced the NO-dependent toxicity of proinflammatory cytokines toward MIN6 cells, while IL-17-specific neutralizing antibody partially reduced the NO production and rescued insulinoma cells and pancreatic islets from NO-dependent damage induced by activated T cells. Finally, a significant increase in blood IL-17 levels was observed in a multiple low-dose streptozotocin model of diabetes, suggesting that T cell-derived IL-17 might be involved in NO-dependent damage of beta cells in this disease. Received 14 June 2005; received after revision 17 September 2005; accepted 21 September 2005     

Fluorogenic amines in the notochords of chick embryos treated by cholinergics]

The investigation of 3 day old notochords by the fluorescence method of Falck and Owman showed an increase of the fluorescence after treatment of the chick embryos at 48 hrs of incubation, with nicotine sulfate or carbachol. The addition of norepinephrine or L-Dopa emphasized the formaldehyde induced fluorescence. The simultaneous treatment with a cholinergic agent and atropine, propranolol or reserpine decreased or suppressed the fluorescence. These results demonstrate the existence of a relationship between the treatment with a cholinergic agent and the amount of chordal biogenic amines.     

Effects of castration, estradiol and testosterone on tubulin levels of the medial basal hypothalamus and the adenohypophysis of the rat.

Tubulin levels of the medial basal hypothalamus (MBH) were greater in male than in female rats. Orchidectomy brought about a decrease of MBH tubulin concentration, whereas testosterone injection augmented it in the MBH and adenohypophysis. Estradiol administration augmented MBH tubulin and protein concentration.