Immunohistochemical localization of beta-LPH in the human hypothalamus.
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Hypothalamus↗
Biomedical subjects
G Pelletier
Publications and source records attributed to G Pelletier.
Localization of alpha-melanocyte-stimulating hormone in rat brain and pituitary.
The distribution of alpha-melanocyte-stimulating hormone (alpha-MSH) was studied in the rat brain with an immunoperoxidase technique. alpha-MSH-containing cells were found in the arcuate nucleus of the hypothalamus. Cells staining for alpha-MSH were also localized in the intermediate lobe of the pituitary. alpha-MSH-containing nerve fibers extended throughout regions of the hypothalamus, thalamus, and midbrain. Two weeks after hypophysectomy, alpha-MSH-positive cells anf fibers were still present in the brain. These results indicate that alpha-MSH of non-pituitary origin is synthesized and stored by neural structures in the rat brain. The detection of alpha-MSH by radioimmunoassay in the rat brain and pituitary supports these observations.
Animals↗
Inhibition of spermatogenesis in the rat by treatment with [D-Ala6, Des-Gly-NH210] LHRH ethylamide.
The effect of treatment with a potent LHRH agonist, [D-Ala6, Des-Gly-NH210]LHRH ethylamide, injected at the low dose of 100 ng, twice a week, was evaluated on spermatogenesis in the rat. Significant degenerative changes of seminiferous tubules could be observed after two weeks of treatment. These changes were progressive and led to a marked inhibition of spermatogenesis after four to eight weeks of treatment. Testis weight was decreased to approximately 50% of control after eight weeks of treatment.
Animals↗
Identification of human anterior pituitary cells by immunoelectron microscopy.
An attempt was made to classify human pituitary cell types by electron microscopic immunohistochemistry. The immunoperoxidase technique involving the use of the peroxidase-antiperoxidase complex was applied to thin sections of human pituitaries removed surgically for breast cancer or diabetic retinopathy. Using specific antibodies against human PRL, GH, beta-FSH, beta-LH, beta-TSH, and porcine ACTH, the localization of each hormone was studied. Identification of 5 human pituitary cells was possible: 1) The PRL-secreting cell contains round or slightly ovoid secretory granules of a diameter of 275-350 nm. 2) The GH-secreting cell is densely granulated with granule diameters ranging from 350-500 nm. 3) The gonadotrophic cell, which stains for both beta-FSH and beta-LH, is characterized by the presence of a varying number of secretory granules ranging from 275-375 nm. 4) The cortico-lipotrophic cell has numerous granules of about 375-550 nm in diameter. 5) The TSH-secreting cell contains small secretory granules of about 125-200 nm in diameter. Another cell type of which the small secretory granules of about 100 nm in diameter could not be stained by any of the antisera was also observed. This ultrastructural identification of human pituitary cells should contribute to a better understanding of the pathophysiology of the human pituitary.
Adrenocorticotropic Hormone↗
[Immunochemical localization of the substance P in the neural system].
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Animals↗
Pituitary adenomas in Cushing's disease. A histologic, ultrastructural, and immunocytochemical study.
Twenty-two pituitary adenomas in Cushing's disease were removed by transsphenoidal surgery. In six patients the pituitary tumor had become manifest following adrenalectomy (Nelson's syndrome). Sixteen tumors were microadenomas measuring from 2 to 9 mm, while two were diffuse invasive adenomas verified at postmortem examination. Light microscopy showed that the tumors were made of basophillic cells containing PAS-positive granules that stained blue with Herlant tetrachrome and lead hematoxylin. Immunocytochemical studies showed that the granules stained positively with antiserum to adrenocorticotrophic hormone (ACTH) or to beta-lipotropic hormone (beta-LPH) and the peroxidase-antiperoxidase complex. Electron microscopic study of the tumor cells showed ACTH and beta-LPH containing granules varying in size, shape, and amount. Perinuclear bundles of 70 A microfilaments constituted a specific ultrastructural finding.
Adenoma↗
Immunohistochemical localization of somatostatin in the human hypothalamus.
In order to identify clearly the nervous structures containing somatostatin in the human hypothalamus, an immunohistochemical localization of this neurohormone was performed at light-microscopic level. Using a antiserum specific to somatostatin and the unlabeled antibody peroxidase-antiperoxidase technique, we have found somatostatin in neurons with cell bodies in an area in the anterior hypothalamus corresponding to the infundibular nucleus. Somatostatin-containing fibers were also detected in the neurovascular zone of the pituitary stalk, suggesting that somatostatin is released in that region to reach the capillaries in the pituitary portal plexus. A large bundle of somatostatin fibers extending from the anterior part of the paraventricular nucleus up to the posterior portion of the mammillary bodies has also been detected. The role of these fibers still remains to be clarified.
Adult↗
Ontogeny of neurophysin in the rat pituitary gland. An electron microscope immunohistochemical study.
The ontogenic development of neurophysin has not been investigated so far. To study this problem, electron microscopic immunohistochemistry was performed on ultrathin sections of the posterior pituitary of foetal and newborn rats. A concomitant appearance of secretory granules and neurophysin was first noted in the posterior pituitary of 18-day foetus. Neurophysin was detected only in the secretory granules, all of which were labelled. The number of granules (75-110 nm in diameter) as well as the intensity of the reaction for neurophysin increased as the foetus became older. In the newborn rat, the secretory granules were more numerous and showed a strong neurophysin positive reaction. The results support the hypothesis that neurophysin is an essential component for the formation of the secretory granules in the hypothalamo-neurophypophysial system.
Animals↗
Somatostatin: electron microscope immunohistochemical localization in secretory neurons of rat hypothalamus.
Somatostatin, the hypothalamic hormone which inhibits the secretion of growth hormone by the pituitary, has been localized in the rat hypothalamus by using electron microscope immunohistochemistry. Somatostatin occurs in secretory granules (80 to 110 nm in diameter) of a few neurons located in the hypothalamic periventricular nucleus. These observations establish the identity of neurosecretory neurons involved in the regulation of adenohypophyseal secretion.
Animals↗
Light microscope radioautographic study of glycoprotein secretion in the hypothalamic-neurohypophysial system of the rat, after L-fucose-3H injection.
Fucose-3H was injected into the cerebral ventricle of rats that were killed at several time intervals after injection. Semi-thin sections of the supraoptic nucleus and neurohypophysis were processed for radioautography and analysed quantitatively. Silver grains indicating the site of fucoselabeled glycoproteins were first located at the perinuclear region of the secretory neurons. The highest silver-grain density in these cells was observed at 2 h after injection , declining afterwards. Silver grains over the neurohypophysis were observed from 2 h on, reached a peak at 1 day after injection and decreased in the subsequent time intervals. The distributions of the silver grains over the neurohypophysis fitted Poissonian distributions and these were shown to be heterogeneous at the several time intervals. Pituicytes were not labeled. The percentage of silver grains over the Herring bodies increased with time. In rats deprived of water after fucose-3H injection there was a great increase in the release of labeled glycoproteins from the neurohypophysis. These results indicate that the glycoproteins synthesized by the secretory neurons of the hypothalamic nuclei are secreted in the neurohypophysis.
Animals↗
Electron microscopic immunohistochemical localization of alpha-msh in the rat brain.
Using an immunohistochemical technique at the electron microscopic level, it has been shown that alpha-MSH is localized within the small vesicles of a few cell bodies found in the arcuate nucleus and numerous nerve fibers widely distributed throughout the brain. These findings suggest that alpha-MSH could possibly be considered as a neurotransmitter.
Animals↗
Purification of plasma membrane fractions from the bovine pars intermedia and neurohypophyseal lobe and properties of associated adenylate cyclase.
A procedure for the isolation of plasma-membrane-enriched fractions from bovine 'pars intermedia' and neurohypophysis is described. Various fractions are isolated by differential centrifugation and discontinuous sucrose density gradients. The plasma-membrane-enriched fractions have a density in sucrose of 1.14 and 1.16 and the yields are 1.8 mg and 1.5 mg per gram of tissue for the pars intermedia and neural lobe, respectively. The fractions are characterized by electron microscopy and enzymatic assays. The plasma membrane fractions are mainly vesicular in nature and are free of nuclei, mitochondria, and microsomes when examined by electron microscopy. 5'-Nucleotidase (EC 3.1.3.5) and Mg2+-(Na+ + K+)-ATPase (EC 3.6.1.3) activities are concentrated in the plasma-membrane-enriched fraction. Also, adenylate cyclase (EC 4.61.1) shows a 5 to 10-fold purification in the isolated membrane fraction. NaF (10mM) gives a two to three-fold stimulation of enzymatic activity in all fractions studied The yields of adenylate cyclase, 5'-nucleotidase, and Mg2+-(Na+ +K+)-ATPase are about 6% in the membrane fraction.
Adenosine Triphosphatases↗
Electron microscope immunohistochemical localization of substance P in the central nervous system of the rat.
Substance P is an undecapeptide that is distributed in many areas of the central nervous system. In order to clearly identify the structures and organelles containing substance P, an immunohistochemical localization of this peptide was performed at the ultrastructural level. Substance P was detected in dense core vesicles of many nerve endings in both the amygdaloid nucleus and the substantia gelatinosa of the spinal cord. These findings support the hypothesis that substance P could act as a neurotransmitter.
Amygdala↗
Immunohistochemical localization of beta-lipotropic hormone in the pituitary gland.
Identification of the beta-lipotropic hormone (beta-LPH)-producing cells in several species, including man, was performed with the technique involving use of the unlabeled antibody and peroxidase-antiperoxidase complex. Serial paraffin and ultrathin sections were treated for detection of both beta-LPH and ACTH at the light and electron microscopic levels. It was clearly shown that beta-LPH could be found only in the corticotropic cells located in the pars intermedia and pars distalis of all species studied. At the electron microscope level, it could be established that beta-LPH is contained in all the secretory granules of positive cells. These results suggest that beta-LPH is stored in the same secretory granules as ACTH and that both hormones are released together during granule extrusion.
Animals↗
Cure of Cushing's disease by transsphenoidal removal of a microadenoma from a pituitary gland despite a radiographically normal sella turcica.
A 37-year-old woman had symptoms of Cushing's disease for two years. Galactorrhea was present. The diagnosis was confirmed by finding intermittently elevated urinary 17-hydroxysteroids, absent circadian rhythm, and elevated plasma ACTH. Plasma prolactin was slightly elevated. Films of the sella turcica were normal. A 9 mm basophilic microadenoma was removed by the transphenoidal approach. Immunocytochemical and electron-microscopic studies showed that the tumor was composed exclusively of ACTH secreting cells. Endocrine re-evaluation one year later revealed normal adrenal function. Serum prolactin had returned to normal. This case provides further evidence that Cushing's disease can be caused by a pituitary microadenoma insufficient in size to deform the sella.
Adenoma, Basophil↗
Identification of four cell types in the human endocrine pancreas by immunoelectron microscopy.
In order to correlate the different cell types of the human endocrine pancreas to a specific secretion product, an immunoelectron microscopic localization of the hormones whose production had been attributed to pancreatic islets was conducted. Glucagon and insulin were respectively localized in the typical A- and B-cells, whereas no subclasses of A-cells could be identified. With antibodies that reacted with the gastrin cells in the human gastric mucosa, it was not possible to detect gastrin in any of the islet cell types. In confirmation of recent results obtained by light microscopy, somatostatin was found in all the typical D-cells containing large, weakly electron-dense secretory granules. The human pancreatic polypeptide (HPP), a newly postulated hormone, was clearly associated with a fourth cell type, which is characterized by the presence of small secretory granules (100-150 nm.). These results suggest that each of the four cell types that are easily identifiable by ultrastructural observations is responsible for the production of a specific secretory product.
Fluorescent Antibody Technique↗
Immunohistochemical localization of human pancreatic polypeptide (HPP) in the human endocrine pancreas.
In order to clearly identify the cell type responsible for production of human pancreatic polypeptide (HPP), a newly postulated hormone, we have conducted an immunohistochemical detection of this peptide in the human endocrine pancreas at both light and electron microscopy levels. It was shown that HPP containing cells are located both in endocrine and exocrine pancreatic tissue. In the islets, the positive cells are very few in number and are characterized by an elongated shape and the presence of small secretory granules of about 150 nm in diameter. The presence of HPP in an endocrine cell type reinforce the hypothesis that this peptide is a hormone.
Histocytochemistry↗
Immunohistochemical localization of a new pancreatic polypeptide.
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Animals↗