HISTOLOGICAL ALTERATIONS IN THE RAT PITUITARY TRANSPLANTED TO THE EYE

1961 ◽  
Vol 23 (2) ◽  
pp. 109-117 ◽  
Author(s):  
K. KOVÁCS
Keyword(s):  
Pituitary Gland ◽  
Anterior Chamber ◽  
Functional Activity ◽  
Anterior Pituitary ◽  
Peripheral Zone ◽  
Necrotic Area ◽  
Histological Alterations ◽  
Rat Pituitary ◽  
Intraocular Grafts ◽  
Ischaemic Necrosis

SUMMARY Homotransplantation of the anterior pituitary gland of rats was made into the anterior chamber of the eye. The centre of the grafts developed ischaemic necrosis, but the peripheral zone remained alive to a depth of about 100 μ. During the next 6 weeks there was no evidence of significant regeneration or atrophy of this live peripheral zone, and mitoses were not observed there. The gradual resorption and scarring of the central necrotic area led to a diminution of the overall size of the graft. In the surviving tissue nearly all the chromophil cells became completely degranulated during the first week or two. After 6 weeks only very rare shrunken basophil cells remained, although a few acidophil cells could still be identified. From previous work it is known that such intraocular grafts have very little functional activity. This may possibly be because of the absence of any direct connexion between the graft and the hypothalamus, but the reduction of the total amount of parenchyma may also be an important factor.

Cyproheptadine and desmethylcyproheptadine directly inhibit the release of adrenocorticotrophin and β-lipotrophin/β-endorphin activity from the neurointermediate lobe of the rat pituitary gland

1983 ◽  
Vol 96 (3) ◽  
pp. 395-400 ◽  
Author(s):  
S. W. J. Lamberts ◽  
E. G. Bons ◽  
P. Uitterlinden ◽  
W. H. Hackeng
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Serotonin Receptor ◽  
Direct Action ◽  
Anterior Pituitary Gland ◽  
Hormone Release ◽  
Neurointermediate Lobe ◽  
Rat Pituitary

Cyproheptadine and its metabolite desmethylcyproheptadine were shown to suppress directly the release of adrenocorticotrophin (ACTH) and β-lipotrophin/β-endorphin activity from the neurointermediate lobe of the pituitary gland incubated in vitro. Neither compound affected the release of ACTH from the anterior pituitary gland. Serotonin stimulated the release of ACTH and β-lipotrophin/β-endorphin activity from the neurointermediate lobe, but did not influence the (desmethyl)cyproheptadine-mediated inhibition of hormone release. These results indicate that serotonin and cyproheptadine affect hormone release by the neurointermediate lobe by a direct action. The effect of cyproheptadine, however, might not be exerted by a serotonin receptor.

Regulation of the TRH-like peptide pyroglutamyl-glutamyl-prolineamide in the rat anterior pituitary gland

1995 ◽  
Vol 145 (1) ◽  
pp. 43-49 ◽  
Author(s):  
J M M Rondeel ◽  
W Klootwijk ◽  
E Linkels ◽  
G A C van Haasteren ◽  
W J de Greef ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Sex Difference ◽  
Anterior Pituitary ◽  
Biological Significance ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Anterior Pituitary Gland ◽  
Female Rats ◽  
Male Rats ◽  
Rat Pituitary

Abstract TRH-like peptides share the N- and C-terminal amino acids with TRH (pGlu-His-Pro-NH2) but differ in the middle amino acid residue. One of them, pGlu-Glu-Pro-NH2 (<EEP-NH2; EEP) is present in the rat pituitary gland, but its biological significance is unknown. We investigated the localization and regulation of this tripeptide in the rat pituitary gland. To distinguish between TRH and EEP two antisera were used for RIA: specificity of antiserum 4319 for the TRH-like peptides pGlu-Phe-Pro-NH2 and EEP was equal to or greater than that for TRH, whereas antiserum 8880 is TRH-specific. Our RIA data showed the presence of a TRH-like peptide in the anterior pituitary gland (AP) and of TRH in the posterior pituitary gland (PP). The TRH-like peptide in the AP was identified on anion-exchange chromatography and subsequent HPLC as EEP. Pathophysiological conditions such as altered thyroid and adrenal status and suckling did not affect pituitary gland levels of EEP. In general, however, there is a clear sex difference: levels of EEP are higher in male than in female rats. In both sexes gonadectomy leads to a substantial two- to threefold rise in EEP levels, abolishing the sex difference. Testosterone administration to gonadectomized male rats normalizes levels of EEP again. Disulfiram, an inhibitor of the enzyme peptidylglycine α-amidating monooxygenase, reduced levels of EEP in the AP by approximately 50%. In conclusion: 1) the TRH-like peptide EEP is present in the AP, whereas TRH is confined to the PP, 2) levels of EEP in the AP are regulated by sex steroids, 3) EEP is actively amidated in the AP and thus seems to be produced from a glycine-extended progenitor sequence. Journal of Endocrinology (1995) 145, 43–49

scholarly journals Role of GPER in the anterior pituitary gland focusing on lactotroph function

2019 ◽  
Vol 240 (2) ◽  
pp. 99-110 ◽  
Author(s):  
María Andrea Camilletti ◽  
Alejandra Abeledo-Machado ◽  
Jimena Ferraris ◽  
Pablo A Pérez ◽  
Erika Y Faraoni ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Steroid Receptors ◽  
Ex Vivo ◽  
Hormone Replacement ◽  
Pituitary Cells ◽  
Ovarian Steroids ◽  
Rat Pituitary ◽  
High Level

Ovarian steroids control a variety of physiological functions. They exert actions through classical nuclear steroid receptors, but rapid non-genomic actions through specific membrane steroid receptors have been also described. In this study, we demonstrate that the G-protein-coupled estrogen receptor (GPER) is expressed in the rat pituitary gland and, at a high level, in the lactotroph population. Our results revealed that ~40% of the anterior pituitary cells are GPER positive and ~35% of the lactotrophs are GPER positive. By immunocytochemical and immuno-electron-microscopy studies, we demonstrated that GPER is localized in the plasmatic membrane but is also associated to the endoplasmic reticulum in rat lactotrophs. Moreover, we found that local Gper expression is regulated negatively by 17β-estradiol (E2) and progesterone (P4) and fluctuates during the estrus cycle, being minimal in proestrus. Interestingly, lack of ovarian steroids after an ovariectomy (OVX) significantly increased pituitary GPER expression specifically in the three morphologically different subtypes of lactotrophs. We found a rapid estradiol stimulatory effect on PRL secretion mediated by GPER, both in vitro and ex vivo, using a GPER agonist G1, and this effect was prevented by the GPER antagonist G36, demonstrating a novel role for this receptor. Then, the increased pituitary GPER expression after OVX could lead to alterations in the pituitary function as all three lactotroph subtypes are target of GPER ligand and could be involved in the PRL secretion mediated by GPER. Therefore, it should be taken into consideration in the response of the gland to an eventual hormone replacement therapy.

FUNCTIONAL AND MORPHOLOGICAL OBSERVATIONS ON THE RAT PITUITARY GRAFTED INTO THE ANTERIOR CHAMBER OF THE EYE

1959 ◽  
Vol 19 (2) ◽  
pp. 164-173 ◽  
Author(s):  
L. MARTINI ◽  
A. DE POLI ◽  
A. PECILE ◽  
S. SAITO ◽  
F. TANI
Keyword(s):  
Anterior Chamber ◽  
Median Eminence ◽  
Anterior Pituitary ◽  
Sella Turcica ◽  
Adrenal Weight ◽  
Acth Secretion ◽  
Pituitary Tissue ◽  
Lysine Vasopressin ◽  
Rat Pituitary ◽  
Hypophysectomized Rats

SUMMARY It is shown that anterior pituitary tissue grafted into hypophysectomized rats and lacking any connexion with the median eminence does not retain any somatotrophic or gonadotrophic activities, but has some adrenocorticotrophic (ACTH) and thyrotrophic (TSH) activities. This conclusion is based on: (1) the partial maintenance of thyroid and adrenal weight; (2) the results of studies on 131I uptake and on TSH concentration in the grafted pituitaries; (3) the persistence of significant adrenocorticotrophic responses to Pitressin, lysine-vasopressin and Guillemin's fraction D; (4) the presence of histological and histochemical signs of activity in the grafted gland. The subnormal levels of secretion observed in the pituitary grafted into sites far removed from the sella turcica, seem to depend on the lack of some neurohumoral stimulus which normally activates the intact pituitary via the hypophysio-portal vessels. Evidence is given that vasopressin may be the hypothalamic neurohumor involved in ACTH secretion, and that the ACTH-releasing activity of Guillemin's fraction D may be accounted for by its vasopressin content.

scholarly journals The presence of cholecystokinin B receptors in rat pituitary gland and GH3, a rat anterior pituitary tumor cell line.

1991 ◽  
Vol 55 ◽  
pp. 355
Author(s):  
Mari Takamiya ◽  
Hiroyuki Yoshizaki ◽  
Atsuko Hanayama ◽  
Hiromi Nagase ◽  
Tsutomu Kudoh ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Pituitary Gland ◽  
Cell Line ◽  
Pituitary Tumor ◽  
Anterior Pituitary ◽  
Tumor Cell Line ◽  
Rat Pituitary ◽  
Pituitary Tumor Cell

Evidence for direct action of calcitonin in the rat pituitary gland

1989 ◽  
Vol 120 (5) ◽  
pp. 682-688 ◽  
Author(s):  
G. Morel ◽  
J.-G. Chabot ◽  
A. Enjalbert ◽  
M. Priam ◽  
P. M. Dubois
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Direct Action ◽  
Secretory Granules ◽  
In Vitro Study ◽  
Male Rat ◽  
Pituitary Cells ◽  
Cytoplasmic Matrix ◽  
Rat Pituitary

Abstract. Classic concepts of calcitonin (CT) function have focused on the effects of CT on calcium homeostasis. More recently CT actions on brain and pituitary have been investigated. In order to evaluate the effects of CT on the anterior pituitary gland we studied the action(s) of CT in vitro and visualized endogenous CT in adult male rat pituitary gland by immunocytochemistry on ultrathin sections obtained by cryoultramicomy. In vitro study using dispersed anterior pituitary cells indicated that CT stimulated the secretion of PRL, whereas the secretion of GH, TSH and LH was not affected. CT-like immunoreactivity was observed in lactotropes only. The other pituitary cell types were not immunoreactive. In lactotropes, immunostaining was observed in the cytoplasm and in the nucleus. In the cytoplasm, CT-like immunoreactivity was visuzalized in the cytoplasmic matrix and in the secretory granules. In the nucleus, immunostaining was distributed primarly in the euchromatin, in the vincinity of heterochromatin region. CT-like immunoreactivity was also observed at the plasma membrane but was only scarce. No reaction product was found when anti-CT serum pre-incubated with CT was used. In conclusion, these results bring evidence for a direct action of CT on lactotrope regulation in vitro as well as in intact animals.

The influence of adrenal hormone status on neuroendocrine peptides in the rat anterior pituitary gland

1990 ◽  
Vol 127 (3) ◽  
pp. 437-NP ◽  
Author(s):  
P. M. Jones ◽  
D. J. O'Halloran ◽  
M. A. Ghatei ◽  
J. Domin ◽  
S. R. Bloom
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Anterior Pituitary Gland ◽  
Male Rat ◽  
Mrna Levels ◽  
Adrenal Hormone ◽  
Rat Pituitary ◽  
Hormone Status ◽  
Anterior Pituitary Function ◽  
Wet Weight

ABSTRACT Neuropeptide Y (NPY), neurotensin (NT), substance P (SP) and vasoactive intestinal peptide (VIP) are four structurally unrelated neuroendocrine peptides which affect anterior pituitary function. All four peptides appear to be locally synthesized in the anterior pituitary gland and have been shown to be regulated by thyroid and/or sex hormone status. We show here that NT, SP and VIP but not NPY are influenced by adrenal hormone status in the male rat pituitary gland. Adrenalectomy increased the content of VIP (35·4±4·0 (s.e.m.) vs control 11·9±1·1 pmol/g wet weight) but decreased that of SP (18·8±2·3 vs control 36·7 ±3·9 pmol/g wet weight). Adrenalectomy combined with castration decreased the content of SP (14·6±3·5 vs control 36·7±3·9 pmol/g wet weight) but had no effect on VIP content. Treatment with dexamethasone produced significant decreases in NT, SP and VIP contents (17·8±2·3 vs control 32·6±3·4 pmol/g wet weight, 5·5±0·9 vs control 36·7±3·9 pmol/g wet weight and 4·2±0·6 vs control 11·9±1·1 pmol/g wet weight respectively). The changes in pituitary peptide contents occurred in parallel with changes in mRNA levels, suggesting that alterations in glucocorticoid hormone status can alter the synthesis of these peptides. These results, together with the known effects of these neuroendocrine peptides suggest possible functions for locally produced SP and VIP in regulating the secretion of adrenocorticotrophin and/or other proopiomelanocortin-derived peptides. The differential effects of adrenalectomy and adrenalectomy combined with castration on VIP suggests that the regulation of this pituitary peptide is complex, and may be dependent, in part at least, on gonadal factors. Journal of Endocrinology (1990) 127, 437–444

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