scholarly journals Cyclic Changes In The Hypothalamo Neurohypophysial System of Xenentodon Cancila (HAM.)

2013 ◽  
Vol 1 (02) ◽  
pp. 12-19
Author(s):  
Z. B. Khuroo
Keyword(s):  
Pituitary Gland ◽  
Close Association ◽  
Third Ventricle ◽  
Neurosecretory System ◽  
Pars Intermedia ◽  
Intermediate Lobe ◽  
Optic Chiasma ◽  
Hypothalamic Nuclei ◽  
Xenentodon Cancila ◽  
Cyclic Changes

The presence of functional hypothalamo-hypophysial neurosecretory system in vertebrates has led to revise earlier views regarding the hypothalamus-pituitary relationship. The hypothalamo-neurohypophysial system which consists of hypothalamic nuclei, their axonal fibres forming tractus preoptico-hypophyses and the neurohypophysis) works as a morphological as well as a physiological connection between the hypothalamus and the pituitary gland. In fishes, fibres from the neurosecretory hypothalamic nuclei terminate in the neurohypophysis, which remains inter digitized with the adenohypophysis and provides a very close association between the neurosecretory fibres and pars intermedia of the pituitary gland forming a neuro-intermediate lobe. Hypothalamo-Neurosecretory complex of Xenentodon cancila consists of Nucleus Pre-opticus (NPO), Nucleus Lateralis Tuberis (NLT) and their axonal tracts. NPO is a paired structure situated on either side of the third ventricle anterodorsal to the optic chiasma. NPO is divisible into a dorsal Pars Magnocellularis (PMC) consisting of large neurosecretory cells and Pars Parvocellularis (PPC) formed of smaller neurons. Neurons of PMC and PPC contribute beaded axons to form neurohypophysial tract. Herring bodies are seen in the anterior as well as posterior neurohypophysis.

Interleukin-1β stimulates cell proliferation in the intermediate lobe of the rat pituitary gland

1994 ◽  
Vol 140 (3) ◽  
pp. 337-341 ◽  
Author(s):  
H Stępień ◽  
G Żerek-Mełen ◽  
S Mucha ◽  
K Winczyk ◽  
J Fryczak
Keyword(s):  
Cell Proliferation ◽  
Cell Growth ◽  
Pituitary Gland ◽  
Molecular Forms ◽  
Brdu Incorporation ◽  
Immunocytochemical Staining ◽  
Pars Intermedia ◽  
Intermediate Lobe ◽  
Intermediate Cell ◽  
Receptor Antibody

Abstract Interleukin-1 (IL-1) is a multifunctional monokine which possesses an impressive array of diverse actions relating to the function of the immune system. IL-1 is present and formed locally in the brain as demonstrated by biochemical and immunocytochemical methods. Various immunomodulatory and neuroendocrine effects of IL-1 have been reported, including induction of several morphological changes in the endocrine cells of experimental animals and humans. IL-1 is present in two molecular forms (IL-1α and IL-1β) that activate specific receptors for IL-1. In the present study we investigated the possible effect of recombinant human IL-1α and IL-1β and recently cloned anti-human IL-1 receptor antibody (M10) on cell proliferation in the anterior and the intermediate lobe of the pituitary gland of the rat. In vivo labelling with bromodeoxyuridine (BrdU) and immunocytochemical staining with anti-BrdU monoclonal antibody were used as a sensitive index of cell proliferation. IL-1β was found to stimulate dose-dependently (0·1–10 μg/kg body weight) incorporation of BrdU into pituitary intermediate cell nuclei, and positive correlation between the tested doses of IL-1β and BrdU-labelling index was noted (r=0·89; P<0·01). This IL-1β-induced stimulation of pituitary pars intermedia cell proliferation was receptor specific, since stimulation was blocked by anti-IL-1 receptor antibody. On the other hand, recombinant human IL-1α did not affect BrdU incorporation and the proliferation of pituitary pars intermedia cells. In addition, neither of the cytokines tested in the same experimental conditions showed any effect on the cell growth of the pituitary pars anterior. These results suggest that IL-1β may be involved in the regulation of the cell growth of the pituitary intermediate lobe in rats. Journal of Endocrinology (1994) 140, 337–341

Memoirs: A Study of the Histology of the Pituitary Gland of the Skate

1936 ◽  
Vol s2-78 (312) ◽  
pp. 637-651
Author(s):  
N. H. HOWES
Keyword(s):  
Pituitary Gland ◽  
Ventral Surface ◽  
Anterior Region ◽  
Pars Intermedia ◽  
Intermediate Lobe ◽  
Pars Tuberalis ◽  
Ventral Lobe ◽  
Pars Anterior

1. The structure of the pituitary of the adult skate is described. 2. This gland shows two distinct regions of growth which can be correlated with increase of size of the animal. 3. The pars anterior can be subdivided into three regions differing by the staining reactions of their constituent cells: (a) an anterior region where deep-purple chromaphil cells are found; (b) a middle, where they are faintly basiphil; and (c) a posterior, where they are mainly acidophil. 4. It is suggested that these regions are homologous with the pars tuberalis, basiphil, and oxyphil areas respectively of the pars anterior of the mammalian pituitary. 5. The oxyphil cells show an iodine-leucobase reaction similar to that given by the oxyphil cells of the ox pituitary. 6. The ventral lobe is a completely separate structure from the pars intermedia, although it may run along the ventral surface of the latter for some distance. 7. The histology of the neuro-intermediate lobe is described.

Beta-adrenergic stimulation of the release of ACTH- and LPH-related peptides from the pars intermedia of the rat pituitary gland

1981 ◽  
Vol 97 (3) ◽  
pp. 343-351 ◽  
Author(s):  
F.J. H. Tilders ◽  
M. Post ◽  
S. Jackson ◽  
P.J. Lowry ◽  
P. G. Smelik
Keyword(s):  
Pituitary Gland ◽  
Cortical Cell ◽  
Pars Intermedia ◽  
Intermediate Lobe ◽  
Spontaneous Release ◽  
Adrenergic Stimulation ◽  
Similar Time ◽  
In Vitro Superfusion ◽  
Rat Pituitary

Abstract. The intermediate lobe of the rat pituitary gland produces a series of peptides related to ACTH and LPH. The spontaneous and isoproterenol-stimulated release of such peptides was studied during in vitro superfusion of rat neurointermediate lobes with Krebs-Ringer medium. Products released into the superfusion medium were quantified by direct measurement or after chromatography on Sephadex G-50. ACTH bioactivity was determined by use of adrenal cortical cell suspension assay. In addition, NH2-terminal ACTH, CO2H-terminal ACTH, α-MSH and β-endorphin radioimmunoassays were used. The results show that 1. neurointermediate lobes of rats secrete spontaneously various ACTH- and LPH-related peptides in amounts proportional to the amounts in which these peptides are found in extracts of the neurointermediate lobe; 2. the β-adrenergic agonist, isoproterenol, stimulated the spontaneous release of various peptides, including α-MSH, ACTH, CLIP, glycosylated CLIP, and β-endorphin-like peptides; 3. isoproterenol induced a dose-dependent (10−9–10−7 m), parallel increase in the release of α-MSH and ACTH following similar time courses and showing indentical EC50 values (about 10−8 m). Although the spontaneous release of α-MSH and ACTH from rat neurointermediate lobes is not strictly coupled under the conditions used in this study, isoproterenol seems to affect the spontaneous release of these peptides to the same relative extent.

EFFECTS OF PIMOZIDE AND BROMOCRIPTINE ON THE PROLIFERATION OF RAT PITUITARY PARS INTERMEDIA CELLS

1977 ◽  
Vol 75 (3) ◽  
pp. 443-444 ◽  
Author(s):  
J. RYCHTER ◽  
H. STEPIEŃ
Keyword(s):  
Pituitary Gland ◽  
Dopamine Receptor ◽  
Mitotic Activity ◽  
Secretory Cells ◽  
Pars Intermedia ◽  
Dopamine Receptor Agonist ◽  
Intermediate Lobe ◽  
Melanocyte Stimulating Hormone ◽  
Medical Academy ◽  
Rat Pituitary

Department of Experimental Endocrinology, Institute of Endocrinology, Medical Academy of Łódź, Dr. Sterling str. 3, 91-425 Łódź, Poland (Received 31 May 1977) The secretory function of the intermediate lobe of the pituitary gland is under hypothalamic control (Howe, 1973; Hadley & Bagnara, 1975). Penny, Thody, Tilders & Smelik (1977) have suggested that the synthesis and release of melanocyte-stimulating hormone (MSH) is mediated by dopaminergic neurones which make synaptic contact with secretory cells in the pars intermedia (Björklund, Moore, Nobin & Stenevi, 1973). We have attempted to examine whether the dopaminergic mechanism is also involved in the control of the mitotic activity of the pars intermedia cells and have studied the effects of pimozide, a dopamine receptor blocker (Anden, Butcher, Corrodi, Fuxe & Ungerstedt, 1970) and 2-bromo-α-ergocriptine (bromo-criptine), a dopamine receptor agonist (Loew, Vigouret & Jaton, 1976) on the mitotic activity of the pars intermedia of the rat pituitary gland. Twenty-three

Demonstration of desacetyl α-melanocyte-stimulating hormone in fetal and adult human anterior pituitary corticotrophs

1989 ◽  
Vol 120 (3) ◽  
pp. 525-NP ◽  
Author(s):  
P. J. Coates ◽  
I. Doniach ◽  
J. M. P. Holly ◽  
L. H. Rees
Keyword(s):  
Pituitary Gland ◽  
High Performance ◽  
Anterior Lobe ◽  
Pars Intermedia ◽  
Intermediate Lobe ◽  
Human Pituitary ◽  
Human Pituitary Gland ◽  
Melanocyte Stimulating Hormone ◽  
Pars Anterior ◽  
Human Anterior Pituitary

ABSTRACT Immunocytochemistry, radioimmunoassay and high-performance liquid chromatography (HPLC) techniques have been used in combination to investigate the presence of immunoreactive (ir)-α-MSH in the normal human pituitary gland, and to investigate the possible origin of these cells from the fetal pars intermedia. Two separate antisera to α-MSH were employed in immunocytochemistry to distinguish between authentic α-MSH and the desacetyl form. Only desacetyl α-MSH was detected in the pituitary gland of fetal and adult man, in both the pars (zona) intermedia and the pars anterior. In the fetus, a large proportion of the ACTH-containing cells of the anterior lobe also contained ir-α-MSH, while ir-α-MSH containing cells were more sparse in adults. Radioimmunoassay of acid extracts of adult pituitary tissue showed α-MSH levels representing less than 0·05% of the ACTH content of the gland. HPLC analysis of these extracts confirmed that only the desacetyl form was present. These results suggest that α-MSH peptides are synthesized by anterior lobe cells of the human pituitary gland, which are not derived from the fetal pars intermedia. Possible regulatory mechanisms affecting cells which contain ir-α-MSH are discussed, and by comparison with the intermediate lobe of other species it is concluded that there is little evidence for a true intermediate lobe in the human pituitary gland. Journal of Endocrinology (1989) 120, 525–530

Participation of the intermediate lobe of the pituitary gland after prolonged exposure to unpredictable stress in the rat

1983 ◽  
Vol 99 (2) ◽  
pp. 239-243 ◽  
Author(s):  
Irina Pollard
Keyword(s):  
Pituitary Gland ◽  
Psychological Stress ◽  
Ultrastructural Study ◽  
Prolonged Exposure ◽  
Secretory Activity ◽  
Pars Intermedia ◽  
Intermediate Lobe ◽  
Cellular Activity ◽  
Stable Level ◽  
Circulating Levels

An ultrastructural study is described which relates cellular activity in the intermediate lobe of the pituitary gland with circulating levels of corticosterone. Exposure of male CSF rats to a signalled, unpredictable 60-day stress regimen induced intense secretory activity in all cells of the pars intermedia for the first 5 days of stressing, and thereafter secretory activity reverted back to the control condition. Blood corticosterone levels showed an initial extreme increase lasting for the first 5 days of exposure to the stress before gradually falling to re-establish a new stable level of secretion by 40 days. The possible involvement of the intermediate lobe in emotional or psychological stress when corticosterone levels are high is discussed.

The functional significance of glycosylation of proopiomelanocortin in melanotrophs of the mouse pituitary gland

1985 ◽  
Vol 107 (3) ◽  
pp. 365-374 ◽  
Author(s):  
B. G. Jenks ◽  
A. G. H. Ederveen ◽  
J. H. M. Feyen ◽  
A. P. van Overbeeke
Keyword(s):  
Pituitary Gland ◽  
Functional Significance ◽  
Peptide Hormones ◽  
Terminal Region ◽  
Pars Intermedia ◽  
Apparent Effect ◽  
Glycoprotein Precursor ◽  
Tunicamycin Treatment ◽  
Mouse Pituitary

ABSTRACT Pro-opiomelanocortin (POMC) is a glycoprotein precursor for a number of neuropeptides and peptide hormones. The functional significance of the glycosylation of POMC has never been established. Using the antibiotic tunicamycin to block glycosylation of the prohormone in the mouse pars intermedia, we have compared processing of non-glycosylated prohormone with that of glycosylated prohormone in pulse-chase experiments. The peptides produced from non-glycosylated prohormone were shown to be correct cleavage products. Therefore it was concluded that, with the possible exception of peptides from the N-terminal region of the prohormone, the carbohydrate on POMC plays no role in directing cleavage or in protecting the prohormone from random proteolysis. Tunicamycin treatment retarded N-terminal acetylation of melanotrophin but had no apparent effect on acetylation of β-endorphin. The mouse pars intermedia synthesizes two forms of POMC which differ in their degree of glycosylation. Our results indicated that, during secretion, the melanotrophs make no distinction between peptides derived from the two prohormones. J. Endocr. (1985) 107, 365–374

Desensitization of the D-2 dopamine receptor and the β2-adrenoceptor in the intermediate lobe of the rat pituitary gland

1983 ◽  
Vol 5 (6) ◽  
pp. 803-810 ◽  
Author(s):  
K. Miyazaki ◽  
J.M. Saavedra ◽  
T.E. Cote ◽  
J.W. Kebabian
Keyword(s):  
Pituitary Gland ◽  
Dopamine Receptor ◽  
Intermediate Lobe ◽  
Rat Pituitary
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