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At least 847 records · Page 47Linked to original sources
PubMed1989

Gonadectomy induces laminin biosynthesis and basement membrane assembly in anterior pituitary glands of adult rats.

Laminin biosynthesis and basement membrane assembly in anterior pituitary glands of gonadectomized rats were studied by immuno-electron microscopy and radioimmunoassay. Three weeks after gonadectomy, rats received intravenous injections of sheep anti-laminin IgG conjugated to horseradish peroxidase, and glands were fixed and processed for microscopy 1 h later. Peroxidase reaction product uniformly labeled all perivascular and glandular epithelial basement membranes. In addition, reaction product was also found in abnormally multi-layered basement membranes seen especially beneath gonadotrophs, and unusual basement membrane-like structures projecting between gonadotrophs were also labeled. Pituitary sections from gonadectomized rats labeled with pre-embedding immunoperoxidase and post-embedding immunogold techniques also localized intracellular laminin within biosynthetic organelles and "light body" vesicles of gonadotrophs. Neither abnormal basement membrane structures nor intracellular laminin were detected in pituitaries of nongonadectomized, control rats. Radioimmunoassays of pituitary homogenates showed nearly twice as much soluble laminin (approximately 15 ng/gland) in gonadectomized rats than in controls (approximately 8 ng/gland), which paralleled gland growth, but serum laminin concentrations did not differ (approximately 10 ng/ml in both groups). When anterior pituitary glands of gonadectomized rats that received injections of anti-laminin IgG-HRP were fixed 5 days after injection, lengths of unlabeled basement membrane were distributed between labeled lengths. This indicated that new basement membrane was "spliced" into old by a process similar to that seen in normal development. Supplementation of gonadectomized rats with testosterone, however, arrested laminin biosynthesis and basement membrane assembly and reversed glandular hypertrophy. These results indicate that, in an absence of sex hormone feedback, renewed synthesis of basement membrane components occurs in the anterior pituitary and is probably necessary to support the additional growth and differentiation of gonadotrophs and other pituitary cells.

Animals↗
PubMed1994

Expression of high activity of ornithine decarboxylase and occurrence of unusual chromophobic cells in anterior pituitary gland of a novel growth-retarded strain of mice, grm/grm.

Extremely high activity of ornithine decarboxylase (ODC) was detected in the pituitary gland of growth-retarded mice, grm/grm at 2 months after birth. The elevated enzyme activity gradually decreased to the control level in 14 months after birth. In the pituitary gland of the growth-retarded mice, unusual chromophobic cells were also present from the early stages after birth. The chromophobic cells showed conspicuous proliferations and resulted in a distinct hyperplasia of the tissue after 4 months after birth. These findings suggest that ODC is correlated to the progressive transformation of pituitary cells into the chromophobic cells.

Animals↗
PubMed1993

Apoptosis in the anterior pituitary gland of the rat: studies with estrogen and bromocriptine.

Apoptosis was investigated by electron and light microscopy in the anterior pituitary gland of the male Fischer rat in which hyperplasia of prolactin-secreting cells had been induced by estrogen implanted subcutaneously for 6 weeks. Counts by light microscopy of apoptotic cells and cells containing phagocytosed apoptotic bodies increased during a period of 44 h after estrogen withdrawal. Necrosis was present but was not prominent. Administration of bromocriptine after estrogen withdrawal increased apoptotic counts to nearly double those in the absence of bromocriptine. Bromocriptine caused some increase in necrosis. Apoptosis occurred in prolactin-secreting cells identified by immunostaining and in other cells. Phagocytosed apoptotic bodies were seen in folliculo-stellate and not in other cells. It is concluded that apoptosis occurs in the anterior pituitary gland and is induced by bromocriptine. Phagocytosis of apoptotic bodies is a function of the folliculo-stellate cells.

Animals↗
PubMed1989

Size heterogeneity of affinity labeled estrogen receptors in the MtTF4 tumor whose growth is inhibited by estradiol, in pituitary gland and uterus.

UNLABELLED: Estrogen receptors (ER) of the MtTF4 tumor whose growth is inhibited by estradiol (E2) were analyzed and compared to those of tissues whose growth is stimulated by E2 (uterus and pituitary gland). Cytosol prepared in buffer containing protease inhibitors was incubated with [3H]tamoxifen aziridine ([3H]TAZ) in the presence or absence of non-radioactive competitor. The labeled proteins were precipitated, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in denaturing conditions and detected by fluorography. Two classes of ER were identified. The first class is of high molecular weight (Mr = 65,000-64,000). In normal tissues, it is indeed frequently made up of two subtypes as revealed by the presence of a doublet on autoradiograms. In the MtTF4 tumor these subtypes were only rarely suspected and never they were as marked and distinct as in normal tissues. The second class, of low molecular weight (Mr ! 54,000-52,000), is also frequently made up of two subtypes in the uterus and the proportion of this class is higher in the uterus of mature than of immature rats. The MtTF4 tumor contains this class of ER but, due to the presence of non-specifically labeled proteins in this region, its relative amount cannot be estimated and the doublet was exceptionally revealed. In the pituitary gland, this small receptor has not been found. CONCLUSIONS: (i) On the basis of molecular weight analyses, estrogen receptors are heterogeneous, (ii) the ER pattern depends on the type of tissue and the sexual maturity of rats but all the tissues examined contained at least one type of the "classic" high molecular weight receptor, and (iii) no evident correlation was found between the ER pattern and the positive or negative response to estradiol.

Animals↗
PubMed1981

Effects of oestradiol, hypothalamic extracts and luteinizing hormone releasing hormone on rat anterior pituitary gland gonadotrophin release in vitro before and after the preovulatory luteinizing hormone surge at pro-oestrus.

Changes at the anterior pituitary and/or hypothalamic levels which result in selective FSH release during late pro-oestrus in the cyclic rat were investigated. The possible involvement of decreasing serum concentrations of oestrogen during pro-oestrus in such changes was studied. Rats were decapitated at 12.00 h on pro-oestrus, before the onset of the LH surge and first phase of FSH release, or at 24.00 h on pro-oestrus, shortly after the onset of the second or selective phase of FSH release. Other rats were given oestrogen (OE2) at 14.00 h and killed at 24.00 h pro-oestrus. Paired hemi-anterior pituitary glands were incubated with vehicle or OE2 with or without synthetic LH-releasing hormone (LH-RH) or hypothalamic acid extracts prepared from rats killed at 12.00 or 24.00 h on pro-oestrus. At 24.00 h pro-oestrus, serum FSH concentration was high while serum LH concentration was low regardless of whether rats were given OE2. Glands collected and incubated at 24.00 h released more FSH and less LH than did glands collected and incubated at 12.00 h pro-oestrus. Administration of OE2 in vivo and/or in vitro did not affect these responses. The increments in LH and FSH release attributed to LH-RH or hypothalamic extracts in the glands incubated at 24.00 h were not different from those of the glands incubated at 12.00 h. Also, the hypothalamic extracts prepared from rats killed at 24.00 h were no more effective than the extracts prepared from rats killed at 12.00 h in releasing LH or FSH from glands incubated at 12.00 or 24.00 h pro-oestrus. Administration of OE2 in vivo caused a small suppression of LH-RH-induced FSH release. We suggest that a change occurs at the level of the anterior pituitary gland during the period of the LH surge and first phase of FSH release to increase basal FSH secretion selectively and cause, at least in part, the second phase of increased serum FSH. This change is not mediated by a decrease in serum oestrogen concentration. We failed to observe any evidence that LH-RH causes preferential FSH release during late pro-oestrus or that a hypothalamic peptide with a preferential FSh releasing ability is involved in FSH release at this time.

Animals↗
PubMed1984

Isolation, purification and cell-free synthesis of calmodulin from the pig anterior pituitary gland.

Calmodulin was extracted and purified from pig anterior pituitary gland. The protein was characterized by its migration on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis in the presence of Ca2+ or EGTA, its U.V. spectrum between 240 and 290 nm and the activation of calmodulin-deficient cyclic AMP phosphodiesterase. The yield was 370 mg/kg wet wt. mRNA was also extracted from the same tissue and translated in a wheat-germ cell-free translation system. Translated calmodulin was identified by its heat-stability, its co-migration with authentic anterior-pituitary calmodulin on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, its acidic isoelectric point (4.15) on flat-bed isoelectric focusing, its Ca2+-dependent binding to fluphenazine-Sepharose 6B, and its co-elution from this gel with authentic unlabelled calmodulin with EGTA buffer. Calmodulin was not translated as a precursor form. In this tissue it was calculated that calmodulin accounted for 0.5-1% of the total translated protein.

Animals↗
PubMed1984

Dynorphin-(1-13)-like immunoreactivity in central nervous system and pituitary gland of spontaneously hypertensive rats.

We determined by radioimmunoassay concentration of dynorphin-(1-13)-like immunoreactivity in the central nervous system and pituitary gland of spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto rats (WKYs). Compared to WKYs, SHRs had significantly lower levels of dynorphin-(1-13)-like immunoreactivity in the hypothalamus and pituitary gland. However, such immunoreactivity in the cerebral cortex, caudate nucleus, diencephalon, brainstem and spinal cord of SHRs and WKYs were similar.

Animals↗
PubMed1984

Relief of cancer pain in man: alcohol-induced neuroadenolysis vs. electrical stimulation of the pituitary gland.

To explore new methods for the control of intractable pain caused by advanced cancer, the analgesic effect of electrical stimulation of the pituitary gland was investigated in 25 patients. The results were compared with a control study and with the effects of alcohol-induced pituitary neuroadenolysis (NALP) in the same patients. The pain score (0: no pain at all, 4: extreme pain) in the control study was 3.88 +/- 0.33. After electrical stimulation of the pituitary gland it was 1.24 +/- 1.61; and after NALP it was 1.0 +/- 1.60. The pain scores after electrical stimulation and NALP were significantly lower (P less than 0.01) than those in the control study; but there was no significant difference when the two were compared with each other. The duration of pain relief following NALP (59.65 +/- 68.72 days) was significantly longer compared with that recorded following electrical stimulation (2.97 +/- 2.58 days). Autopsy examinations of 3 patients who expired from their malignancies revealed that the pain relief was unrelated to the degree of necrosis induced in the pituitary by alcohol. Naloxone administration did not inhibit the analgesic effect of either NALP or electrical stimulation. The advantages and disadvantages of electrical stimulation, the pain relief mechanism activated by this method, and potential clinical applications are also discussed.

Adult↗
PubMedDate not supplied

Retrospective data on the pituitary gland response during immune and neoplastic processes.

A synthesis of many experimental works performed during the last ten years regarding the nonspecific response of the pituitary gland during some immune and neoplastic processes is presented. Different modalities of the response of pituitary gland cell that vary depending on the antigen type were observed. The TAB vaccine inducing a humoral immune response determined an increased secretory activity of STH and FSH cells which are involved by their secretions in the activation of protein synthesis also including antibodies. The tumoral antigens also representing a stressing factor brought about a more intense activity besides the FSH cells, the ACTH and TSH cells.

Adrenocorticotropic Hormone↗
PubMed1987

Glycosylated growth hormone: detection in murine pituitary gland and evidence of physiological fluctuations.

We examined murine pituitary glands for glycosylated growth hormone using a lectin-binding immunoassay. Every gland tested exhibited significant concanavalin A-binding growth hormone immunoreactivity. The activity was lower in female rats than in males, and lower in lactating than in virgin females. The activity increased following ovariectomy, although total immunoreactive growth hormone was not altered. Administration of estradiol benzoate decreased the concentrations of both types of growth hormone. Progesterone administration, in contrast, did not change concanavalin A-binding growth hormone, but it lowered total growth hormone. Western blotting revealed a growth hormone immunoreactive band 4-5K heavier than the growth hormone monomer in both rat and mouse pituitary. These data suggest the existence in the murine pituitary of a glycosylated form of growth hormone that undergoes physiological fluctuations.

Animals↗
PubMed1983

Autoradiographic localization of quinuclidinyl benzilate binding to rat pituitary gland.

The location of muscarinic receptors in the rat pituitary gland was examined with an autoradiographic technique. Slides containing 10 or 20 micron horizontal sections of tissue were incubated in a solution of 1 n M[3H]quinuclidinyl benzilate (QNB) in phosphate-buffered saline to label muscarinic receptors. Autoradiograms were produced by placing the slides into X-ray cassettes with tritium-sensitive film and processing the film 8-10 weeks later. Minimal binding occurred when sections were incubated in 1 nM[3H]QNB plus 1 microM atropine. Highest specific binding of QNB was found in the anterior and intermediate lobes along their border with the pituitary cleft. Patches of high binding were also seen penetrating the intermediate lobe and at the border between the intermediate and neural lobes. The remainder of the intermediate lobe had background density of autoradiographic grains. Moderate density of specific binding was found throughout the anterior lobe. Low specific binding occurred in the neural lobe.

Animals↗
PubMed1981

Ultrastructural localization of gonadotropin and luteinizing hormone releasing hormone in the pituitary gland of a teleost fish (the platyfish).

Immunoreactive luteinizing hormone releasing hormone (irLHRH) and immunoreactive gonadotropin (irGtH) are demonstrated in the pituitary gland of a teleost fish (Xiphophorus maculatus, the platyfish) at the ultrastructural level. Using a immunoperoxidase procedure, irGtH and irLHRH are specifically localized over the secretory granules of both gonadotropes and some cells of the pars intermedia (PI). All other pituitary cell types lack immunoreactive material. A concept of LHRH receptors on gonadotrope granules is discussed and a new function for a class of PI cells is suggested.

Animals↗
PubMed1989

Amyloid protein of vessels in leptomeninges, cortices, choroid plexuses, and pituitary glands from patients with systemic amyloidosis.

The cerebrum, cerebellum, and choroid plexuses from 16 patients with systemic amyloidosis, and the pituitary glands from 14 of these patients, were investigated histologically and immunohistochemically. Cerebrovascular amyloid (CVA) was found in the leptomeninges and cortices of six patients with systemic amyloidosis, including two patients with amyloid A protein (AA) amyloidosis related to serum amyloid A protein, one with AL amyloidosis related to immunoglobulin light chain (AL), two with familial type I amyloidotic polyneuropathy (FAP), and one with senile systemic amyloidosis (SSA). CVA protein from two patients with FAP reacted with anti-human prealbumin antibody similar to that of the visceral organs of these two patients. CVA in SSA reacted with anti-human prealbumin antibody and anti-beta protein antibody. Vascular amyloid was frequently noted in the pituitary glands and choroid plexuses of patients with systemic amyloidosis, and was found to be identical to that in the visceral organs (heart, kidney, and intestine) of these patients. CVA in the leptomeninges and cortices from two patients with AA amyloidosis and one with AL amyloidosis reacted with anti-beta protein monoclonal antibody but not with anti-human AA monoclonal antibody, anti-human A lambda antisera, and anti-human A kappa antisera. We suggest that amyloid proteins of AA and AL amyloidosis do not readily accumulate in the vessels in the leptomeninges and cortices even though the proteins circulate, and that beta protein is not derived from a serum precursor.

Amyloid↗
PubMedDate not supplied

Duplication of pituitary gland.

We present a case of duplication of the pituitary gland with associated clefts of the hard palate and body of the sphenoid and a midline palatine dermoid. This is an extremely rare malformation with only six previous case reports in the literature. Imaging findings are discussed and literature reviewed for possible morphogenesis, including its association with partial twinning and midline cleft face syndrome.

Abnormalities, Multiple↗
PubMed1977

Protein biosynthesis in vitro by the pars intermedia of the mouse pituitary gland.

During short-term incubations of isolated posterior pituitary glands of the mouse, isotopically labelled amino acids were incorporated into protein by the cells of the pars intermedia. Using labelled leucine, 5-10% of incorporated label was found in a protein (P1) with a molecular weight of about 75 000. Protein P1 could be isoalted from both fresh and incubated tissue, and was a normal and indeed major, secretory product of the ppars intermedia. constituting more than 50% of the protein present.

Animals↗
PubMed1982

Distribution and number of gonadotrophic cells in the pituitary gland of prepubertal female rats.

The localization and number of LH- and FSH-containing cells (LH cells and FSH cells) in the pituitary gland of prepubertal female rats aged 5 micron, 10, 20, 25 and 30 days were determined by means of immunocytochemical light microscopy of 5 horizontal sections. Anti-rat LHbeta and anti-rat FSHbeta were used in combination with the unlabelled peroxidase-antiperoxidase method. The gonadotrophic cells were regularly distributed throughout the pars distalis but at 5 and 10 days of age few LH and FSH cells were found in lateral regions. The numbers of LH and FSH cells per pituitary gland increased with age. The number of LH cells per unit volume of pituitary tissue reached a maximum at 20 days; the number of FSH cells reached a maximum at 15 days and then decreased with increasing age. At all ages except 5 days more LH than FSH cells were counted per unit volume. Some cells reacting with both anti-rat LHbeta and anti-rat FSHbeta were detected. Comparison of the data obtained on the dynamics of cell number with data previously obtained on pituitary gonadotrophin content suggests that at successive prepubertal ages LH and FSH cells contain increasing amounts of their respective hormones.

Animals↗