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Biomedical subjects

F Vandesande

Publications and source records attributed to F Vandesande.

At least 109 records · Page 6Linked to original sources
PubMed1988

Peptidergic innervation of the adrenocorticotropic hormone (ACTH)- and growth hormone (GH)-producing cells in the pars distalis of the sea bass (Dicentrarchus labrax).

Due to its unique organization, the teleost pituitary is an ideal model in which to investigate the relationship of the nervous system with the pituitary endocrine cells. A light microscope immunocytochemical study of the sea bass pituitary revealed six different neuropeptides in nerve fibers which projected into the pituitary neurohypophysis and bordered the adenohypophysial cells. Double staining showed separate nerve fibers immunoreactive for corticotropin-releasing factor (CRF), vasotocin (VT), somatostatin (SRIF), growth hormone-releasing factor (GRF), and neurotensin (NT) in the vicinity of the adrenocorticotropic hormone-releasing cells (ACTH-cells) in the rostral pars distalis (PD). In the proximal PD cholecystokinin (CCK)-, SRIF-, GRF-, and VT-immunoreactive fibers penetrated between the growth hormone-releasing cells (GH-cells). These results suggest a possible role for CCK, GRF, SRIF, and VT in the modulation of GH-cell activity, while the synthesis and/or secretion of the ACTH-cells might be affected by the release of VT, CRF, SRIF, GRF, and NT.

Adrenocorticotropic Hormone↗
PubMed1988

One-step purification of chicken growth hormone from a crude pituitary extract by use of a monoclonal immunoadsorbent.

The immunization of mice with an affinity-purified glycoprotein preparation from chicken pituitary tissue yielded several monoclonal antibodies towards the recently described glycosylated variant of chicken GH. As all these antibodies recognize the classical (non-glycosylated) GH molecule equally well, they provide a suitable tool for the development of both a specific immunoadsorbent and an assay method. This paper deals with the surprising purification power of the immunoadsorbent that was produced with one of the monoclonal antibodies. The resulting preparation was more than 99% pure as assessed by reversed phase high-performance liquid chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, so that no further purification steps were needed before the determination of the amino acid sequence of the material. The efficiency of the purification protocol as determined by a homologous, monoclonal antibody-based radioimmunoassay was virtually absolute. Moreover, the affinity-purified GH preparation was a mixture representing the multiple molecular forms of pituitary chicken GH, including both oligomeres and glycosylated GH. The purified preparations were finally used to demonstrate the hepatic 5'-monodeiodinase-stimulating activity of GH in the chicken embryo (results not shown), in order to prove that the biological activity of the molecule had not been damaged by elution from the immunoadsorbent.

Amino Acids↗
PubMed1988

Heterogeneity of GABAergic cells in cat visual cortex.

Antibodies against neuropeptides and against a vitamin D-dependent calcium-binding protein (CaBP) label small cells with nonpyramidal-like morphology in the cat visual cortex (areas 17, 18, and 19). Since GABAergic cells are interneurons, a double-staining procedure was used to test for the coexistence of cholecystokinin (CCK), somatostatin (SRIF), neuropeptide Y (NPY), corticotropin-releasing factor (CRF), vasoactive intestinal polypeptide (VIP), and CaBP with glutamic acid decarboxylase (GAD). Our results show that CRF and VIP do not coexist with GAD, while the 3 other peptides and CaBP do. Hence GAD-positive cells can be subdivided into 4 broad groups: (1) cells that are only GAD-positive, (2) cells that are GAD- and CaBP-positive, (3) GAD-positive neurons also containing CCK, and (4) GAD-positive cells that also contain SRIF. A small subset of class 2 also contains SRIF and most cells of class 4 also contain NPY. The 4 classes of GAD-positive cells differ in laminar position: class 1 predominates in layers IV and V, classes 2 and 3 in the upper laminae (II and III), and class 4 in the deepest layer (VI).

Animals↗
PubMed1987

Immunocytochemical localization and spatial relation to the adenohypophysis of a somatostatin-like and a corticotropin-releasing factor-like peptide in the brain of four amphibian species.

The distribution of somatostatin (SRIF) - and corticotropin-releasing factor (CRF)-like - immunoreactive material was studied in the brain of four amphibian species (Ambystoma mexicanum, Pleurodeles waltlii, Xenopus laevis, Rana ridibunda) by use of immunocytochemistry. A wide network of SRIF-immunoreactive fibers and numerous perikarya were observed in all amphibians examined, with a dense accumulation of nerve endings in the external layer of the median eminence (ELME). In the representatives of the four amphibian species the CRF-like system was more circumscribed. Immunoreactive perikarya were present in the preoptic area, mainly in a ventrobasal position, and in the interpeduncular nucleus. The tract running along the ventral part of the tuber cinereum ends in the ELME facing the rostroventral lobe of the pars distalis that contains corticotrophs. CRF fibers were scarce or absent in the neural lobe. In all species studied in the present work, CRF fibers end in the area of the ELME close to the pituitary lobe containing corticotrophs. This correlation is similar to that reported for the Japanese quail and several teleosts.

Ambystoma↗
PubMed1987

Glycosylated chicken growth hormone.

In an attempt to raise monoclonal antibodies to chicken pituitary glycoprotein hormones, mice were immunized with the concanavalin A-adsorbed components of a hypophyseal extract. Fusions of these spleen cells with myeloma cells repeatedly yielded hybridoma lines secreting antibodies that recognized specifically the pituitary caudal acidophils, known as the somatotropes. This paper reveals the existence of a glycosylated counterpart of the well-established holoprotein form of chicken growth hormone, similar to what has been established for human growth hormone and prolactin.

Animals↗
PubMed1986

Immunocytochemical identification and localization of the different cell types in the pituitary of the seabass (Dicentrarchus labrax).

Antisera raised against chum salmon prolactin (PRL), trout growth hormone (GH), mammalian adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), luteinizing hormone (LH), and alpha-melanophore-stimulating hormone (alpha-MSH) were used to localize PRL, GH, ACTH, gonadotropic, TSH, and MSH cells in the hypophysis of the teleost Dicentrarchus labrax using the unlabeled peroxidase anti-peroxidase method. In the rostral pars distalis, ACTH cells stained very intensively with anti-ACTH; so did the MSH cells in the pars intermedia. The prolactin cells stained very specifically with anti-prolactin without staining the growth hormone cells. In the proximal pars distalis anti-GH, anti-TSH beta, and anti-LH stained selectively the corresponding cells; with these antisera no cross-reaction with any other cell type was observed. Anti-alpha-MSH only stained cells in the pars intermedia. Some cells in the pars intermedia did not react at all; these could correspond to the PAS-positive cells. A characteristic feature was positive staining with anti-LH in some cell groups encircling the pars intermedia, indicating the fact that in the seabass some cells of the proximal pars distalis surround the pars intermedia.

Adrenocorticotropic Hormone↗
PubMed1986

A new alternative for simultaneous immunohistochemical screening of 96 hybridoma clones for tissue-specific antibody productions selects a monoclonal antibody to insect corpus cardiacum.

In the current search for the elucidation of the true structure of hitherto unidentified 'new' insect neuropeptides we designed a novel screening method to facilitate the primary detection of neurone-specific antibody secreting mouse-mouse hybridoma clones obtained after immunization with neuronal tissue homogenates. The present procedure is principally adapted from a conventional immunohistological test and enables one to rapidly screen 96 (and even more) clones at one time for potential secretion of specific antibodies to different tissue compounds, without the necessity of having a purified antigen. It has proved to be sensitive, rapid, practical and reproducible. As such it promises to be very useful to discriminate amongst the wide range of antibodies to various kinds of materials produced by hybridomas by detecting monoclonal antibodies directed against factors contained in well-defined tissues in which one is interested. This paper also reports the successful application of this method to a primary screening of clones producing murine monoclonal antibodies to substances of insect corpora cardiaca (CC), after immunization with crude antigen preparations.

Animals↗
PubMed1986

CRF-like immunoreactive system in the quail brain.

Nerve cells and fibres immunoreactive for synthetic ovine corticotropin releasing factor were shown to be present in several brain areas of the quail by use of immunocytochemical techniques. CRF-like immunoreactive cell bodies are mainly clustered in the hypothalamic paraventricular nucleus, in the telencephalic nucleus accumbens and in the mesencephalic periventricular grey. The external zone of the anterior median eminence contains a rich network of immunoreactive fibers. CRF-like immunopositive fibers are not restricted to circumventricular organs, but have been observed in several prosencephalic regions and in close proximity of large vasotocin-containing neurons in the supraoptic and paraventricular regions. These observations suggest that, in birds, CRF-like material might be not only involved in the hypothalamic control of anterior pituitary hormone secretion, but also in different functions likely related to neurotransmission or neuromodulation.

Animals↗
PubMed1985

Immunocytochemical localization of somatostatin and cholecystokinin in the cat visual cortex.

Immunocytochemistry was used to examine the morphology and distribution of cholecystokinin-like and somatostatin-like neurons in areas 17, 18 and 19 of cat visual cortex as a function of lamination. Immunoreactive cells of both peptides were observed in all layers of cat visual cortex. While somatostatin-like cells occurred mainly in layers II + III and VI, cholecystokinin-like cells were observed chiefly in the superficial layers (I + II + III). Somatostatin-like cells displayed morphological features of multipolar and bipolar varieties, and cholecystokinin-like cells displayed morphological features of multipolar and bitufted varieties. Similar results were obtained for all 3 areas.

Animals↗
PubMed1985

Active peptides from amphibian skin are also amphibian neuropeptides.

Immunohistochemical data on several newt brain areas showed a heterogeneous system of neuronal elements, immunopositive for antisera specifically directed to different antigenic determinants of tachykinin molecules. Acid extracts of newt brain areas were immunopositive for substance P with an antibody specific for the COOH-terminal (tachykinin determinant) and exhibits an elution profile by gel filtration characteristic to substance P. Bombesin-like immunoreactivity was demonstrable both by immunohistochemistry (fibers and cell bodies in forebrain and hypothalamic areas) and by radioimmunoassay, using an antiserum specific for the mid-region of the molecule. This immunoreactivity was separated into two peaks by gel filtration chromatography. Sauvagine-like material was detected by immunohistochemistry in newt hypothalamus as a loose preoptic cell system and as a thin fiber layer in the outer zone of the median eminence. Double staining procedures demonstrate that sauvagine and CRF are spatially closely related but separable in both the preoptic area and in the median eminence. This data on the presence of several amphibian skin peptides in the CNS of the newt suggests their possible role as neuropeptide.

Amphibian Proteins↗
PubMed1984

Immunohistochemical localization of corticotropin-releasing factor (CRF)-like immunoreactivity in the hypothalamus of the newt, Triturus cristatus.

The distribution of corticotropin-releasing factor (CRF) immunoreactivity was investigated in the hypothalamus and preoptic area of the newt by single and double immunocytochemical procedures. CRF immunopositive cell bodies were seen in the preoptic area (from the anterior wall of the preoptic recess to the dorsal parts of the preoptic nucleus) and in the tuberal portions of the posterior hypothalamus. Abundant nerve fibres are seen in the outer zone of the median eminence, while the pars nervosa lacks CRF-immunoreactivity. CRF immunoreactive material is seemingly separated from neurophysins- and somatostatin immunoreactive cell bodies and fibres.

Animals↗
PubMed1984

Localization of CRF immunoreactivity in the central nervous system of three vertebrate and one insect species.

By use of a specific antiserum against synthetic ovine corticotropin-releasing factor (CRF) in the peroxidase-antiperoxidase (PAP) immunocytochemical procedure (Vandesande and Dierickx 1976), CRF-like antigenic determinants were demonstrated in the central nervous system of a human fetus, the Wistar rat, the frog Rana ridibunda, and the American cockroach Periplaneta americana. The immunoreactive CRF-producing cells occur mainly in the nucleus paraventricularis of the rat, while in Rana ridibunda these cells occur in the nucleus praeopticus. Immunoreactive CRF-containing fibres were also visualized. Very clear CRF-immunoreactive products were observed in the brain as well as the corpora cardiaca (CC) and corpora allata (CA) of the cockroach Periplaneta americana. ACTH-immunoreactivity was also demonstrated in the brain-CC-CA complex of this insect. Double immunohistochemical staining (Vandesande 1983) also revealed that both the CRF- and ACTH-like substances occur in different neurosecretory neurons and nerve fibres. These results suggest that the antigenic determinants of CRF are very similar in vertebrates and insects bespeaking their very long evolutionary history.

Adrenocorticotropic Hormone↗
PubMed1984

Immunocytochemical identification of CRF-like and SRIF-like peptides in the brain and the pituitary of cyprinid fish.

Single and double immunocytochemical techniques were applied to the brain and pituitary of carps and goldfish. With the use of antiserum raised against synthetic corticotropin-releasing factor (CRF), immunoreactive perikarya were observed in the nucleus praeopticus and the nucleus praeopticus periventricularis. CRF-like-immunoreactive hypothalamic nerve fibers reach the pituitary. In cyprinids, some fine fibers enter the rostral neurohypophysis bordered by prolactin- and ACTH cells. Other thicker fibers extend ventrocaudally into the neurointermediate lobe. This CRF-like system appears to differ from the SRIF-like system, which is restricted to the proximal pars distalis of the pituitary containing somatotrophs.

Animals↗
PubMed1984

Somatostatin in the brain and the pituitary of some teleosts. Immunocytochemical identification and the effect of starvation.

Immunocytochemical investigations show that somatostatin (SRIF)-like immunoreactive material is present in the brain and the pituitary of nine different species of teleosts. In the brain, immunoreactive perikarya and fibers are observed in the preoptic periventricular nucleus, the entopeduncular nucleus, the anterior periventricular nucleus, and the nucleus lateralis tuberis. In the pituitary, SRIF-like-immunoreactive fibers occur in the proximal pars distalis (PPD), which contains the growth hormone (GH)-secreting cells. Nerve fibers are scattered among GH cells (cyprinids), or end on the basal lamina at the neuroglandular interface of the PPD (eel, salmonids). In the eel, the proximal neurohypophysis does not penetrate deeply into the PPD that is very poorly vascularized. In some species, e.g. Myoxocephalus, SRIF-like immunoreactive fibers are also observed in the caudal neurohypophysis, and even among MSH cells of the pars intermedia. In long-term starved carps and eels, the amount of SRIF-like material in the pituitary is clearly reduced. A possible role of SRIF in the concomitant stimulation of GH cells is discussed.

Animals↗
PubMed1983

Cholecystokinin varies in the posterior pituitary and external median eminence of the rat according to factors affecting vasopressin and oxytocin.

Using radioimmunoassay (RIA), the content of gastrin-cholecystokinin family peptide immunoreactivity (G-CCK-IR), in the posterointermediate lobe (PIL) of the rat pituitary, has been determined in several experimental conditions. G-CCK-IR levels are significantly higher in males than in females. Salt loading induces a significant decrease of G-CCK-IR in animals of either sex. In males, G-CCK-IR levels are lower than controls 21 days after either castration or daily subcutaneous oestradiol injections. Using immunocytochemistry, G-CCK-IR disappears from the external median eminence 21 days after adrenalectomy. Our results show that, in addition to sex difference, factors affecting the vasopressin and/or oxytocin levels in the posterior pituitary and external median eminence also affect G-CCK-IR in the same regions. Cholecystokinin may therefore be of importance in functions related to these hormones.

Adrenalectomy↗