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At least 883 records · Page 49Linked to original sources
PubMed2006

A pituitary carcinoma secreting TSH and prolactin: a non-secreting adenoma gone awry.

To our knowledge, only one case of a TSH-secreting carcinoma has previously been reported. We describe here a second patient with a pituitary carcinoma producing TSH and prolactin (PRL). A 37-year-old male underwent a left frontotemporal craniotomy in 1996 for a sellar mass. Except for mildly increased PRL and elevated alpha-subunit, hormone evaluation was normal. Pathologic examination revealed a chromophobe adenoma with increased mitotic forms. The patient completed a course of external beam radiation to the pituitary and was prescribed l-thyroxine, bromocriptine, and hydrocortisone. He was lost to follow-up but did well for 6 years, until 2002, when he presented with TSH-dependent thyrotoxicosis and hyperprolactinemia. The patient was started on bromocriptine and propylthiouracil and was, again, lost to follow-up. In 2004, 9 years after his initial presentation, he presented after falling. Magnetic resonance imaging showed two brain masses with associated midline shift. Emergent resection of the larger mass revealed a pituitary cancer with positive staining for PRL, but not for TSH. Nine months later, the patient underwent further debulking of metastatic disease. Although development of a carcinoma from a pituitary adenoma is very rare (<0.5%), macroadenomas that become hormonally active should be suspect for transformation into pituitary cancer.

Adult↗
PubMed1979

Suppression of pituitary secretion of follicle-stimulating hormone by porcine follicular fluid during pro-oestrus and oestrus in the rat: effects on gonadotrophin and steroid secretion, follicular development and ovulation during the following cycle.

In this study, we have examined whether the suppression of raised plasma FSH concentrations at pro-oestrus and/or oestrus by porcine follicular fluid (PFF) affected the development of follicles for ovulation in the next cycle. Adult, 4-day-cyclic rats were injected with PFF or pig serum at various hours of pro-oestrus and oestrus. Plasma FSH levels were suppressed following PFF treatment at any time of pro-oestrus and oestrus. Furthermore, this suppression was always followed by a 'rebound' increase in plasma FSH. In contrast, plasma LH concentrations were unaffected by PFF treatment and neither gonadotrophin was altered by treatment with pig serum. When rats treated with PFF or pig serum were allowed to complete one additional cycle, plasma LH and FSH concentrations at the pro-oestrus and oestrus after treatment were not significantly different among groups regardless of treatment or time of treatment. All ovaries of rats treated with PFF or pig serum on the next pro-oestrus morning before ovulation were histologically similar. Furthermore, all animals ovulated a normal complement of ova at the next oestrus regardless of whether preovulatory, secondary or both increases of plasma FSH had been blocked by PFF treatment during the previous cycle. However, animals given PFF during the preceding cycle, plasma oestradiol and progesterone concentrations were significantly altered on the morning and afternoon of pro-oestrus respectively. These results suggest that increased plasma FSH concentrations at pro-oestrus and oestrus may not be essential for folliculogenesis and ovulation in the subsequent cycle. Alternatively, the 'rebound' of FSH on day 1 of dioestrus after the suppression of both phases of FSH secretion at pro-oestrus and oestrus may be sufficient to provide ovulatory follicles for the next pro-oestrous day.

Animals↗
PubMed1986

An in-situ isolated rat adrenal perfusion system for study of neurally mediated catecholamine secretion: effects of morphine, a Met-enkephalin analogue, and naloxone on catecholamine secretion.

An in-situ isolated rat adrenal perfusion technique has been devised to study the opioid control of neurally mediated adrenomedullary catecholamine release. Adrenomedullary catecholamine secretion was induced by electrical stimulation of the cut end of the left descending thoracic sympathetic chain on platinum electrodes. The half-maximal stimulatory potential (ED50) of the system was 8 V, 20 Hz, with 300 microseconds pulse width. Basal release of catecholamine from the adrenal was constant using a perfusion flow rate of 100-300 microliter/min, but increased significantly with increasing perfusion temperature over the range 36-38 degrees C. Following repetitive 30-s stimulation of the left thoracic sympathetic chain, and 3-min fraction collections, the total amount of catecholamine released per fraction remained within 80-100% of the maximum release for up to eight consecutive stimuli. The release of catecholamines was completely blocked by hexamethonium (0.1 mmol/l), but recovered to pre-blockade values within two further stimuli. Using the ED50 and the first three stimuli as control, the effects of morphine (10 nmol/l-l mmol/l), D-Ala2-MePhe4-Met-enkephalin-(O5)-ol (DAMME; 10 nmol/l-0.1 mmol/l) and naloxone (10 nmol/l-10 mumol/l) on the response to the next three stimuli were compared. Morphine, DAMME or naloxone did not significantly alter the amount of catecholamine released by this form of stimulation. Therefore in the rat, under the conditions used, there is no evidence for mu (mu) or delta (delta) opiate modulation of neurally mediated catecholamine release from the rat adrenal medulla.

Adrenal Glands↗
PubMed1989

High-density lipoproteins (HDL) stimulate placental lactogen secretion in pregnant ewes: further evidence for a role of HDL in placental lactogen secretion during pregnancy.

Previous studies from our laboratory showed that high-density lipoproteins (HDL) stimulate the release of human placental lactogen (PL) from cultured trophoblast cells from normal pregnant women. To determine whether HDL stimulates PL secretion in vivo, ovine HDL was infused over 2-5 min into 11 pregnant ewes (22 separate experiments) at 86-130 days of gestation via an indwelling catheter into the maternal jugular vein. The HDL, freshly prepared from the plasma of pregnant ewes by differential flotation ultracentrifugation, was greater than 99% purified as judged by SDS-PAGE. Plasma samples were obtained from the ewes before and at 0.5-h intervals for 6 h following the infusions and were assayed for PL by a specific homologous radioimmunoassay. The maternal infusion of HDL at doses of 302-784 mg (5.3-13.8 mg/kg body weight) stimulated significant increases in maternal plasma PL concentrations in six out of eight experiments (six ewes), and the infusion of 108-264 mg (1.9-4.6 mg/kg) stimulated plasma PL concentrations in two out of six experiments. In contrast, HDL at doses less than 100 mg were without effect in eight experiments. The response to the HDL infusions was characterized by a sustained increase in plasma PL concentrations beginning 1.5-2.5 h after the infusions, reaching a maximum 274.2 +/- 21.9% of the baseline value (P less than 0.001). In contrast, the maternal infusion of lipoprotein-free plasma proteins or saline had no effect on maternal plasma PL concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Studies into secretions of Tetrahymena: enzymes secreted into inorganic medium.

The peptides secreted by Tetrahymena cells into inorganic medium were chromatographed. Six fractions showing a marked enzyme-like activity were examined for influence on certain physiological parameters of Tetrahymena. The enzymatically active fractions increased the phagocytic activity of Tetrahymena and decreased its binding capacity for lectins and hormone (insulin), but enhanced insulin imprinting at primary interaction. It remains to be clarified whether these effects were due to the enzymatic or other components of the fractions investigated, or to lack of the compensatory influence of the fractions not studied.

Animals↗
PubMed1990

Pharmacology of pepsinogen secretion: influence of pentagastrin on pepsinogen secretion in man.

To investigate the effect of pentagastrin on serum and urinary pepsinogens and gastric pepsin, eight healthy male volunteers were studied twice during continuous intragastric perfusion with either NaCl 0.9% or 0.1 M HCl in random order. To the perfusate 3 mg/ml phenol red was added as inert recovery marker. Gastric content was aspirated in 15-minute samples, 4 basally and subsequently 6 during continuous i.v. infusion of pentagastrin 1.5 micrograms/kg/h. Furthermore, serum and urine samples were collected immediately before and after each test. Gastric pepsin output increased after pentagastrin. There were no differences in basal or stimulated pepsin output during saline or HCl perfusion despite marked differences in intra-gastric acidity and acid delivery to the duodenum. In addition, no significant changes in serum pepsinogen levels or urinary pepsinogen excretion were observed after pentagastrin infusion. It is concluded that pentagastrin stimulates gastric pepsin secretion directly, but does not stimulate the release of pepsinogens into the systemic circulation.

Adult↗
PubMed1990

Analysis of human vaginal secretions using rabbit anti-human vaginal secretions: detection of non-serum proteins.

The antigens detectable in human vaginal secretions (HVS) have been analyzed by using a rabbit anti-HVS serum. After absorption by a pool of human sera, this antiserum on immunoelectrophoretic analysis produced three precipitation lines between the HVS and the antiserum. These lines were found at gamma (a line), beta-gamma (b line) and beta (c line) globulin regions. Their respective incidences of appearance among 59 HVS specimens obtained from 50 women were 46 (78%), 56 (95%) and 29 (49%). Of these HVS specimens, 57 (97%) were positive for one or more of these antigens. These three antigens, a, b, and c can be considered useful markers to determine the presence of the HVS. The origin of the HVS proteins and the influence of the non-serum proteins from the upper genital tracts are also discussed.

Adolescent↗
PubMed1988

Addition of growth hormone secretion signal to basic fibroblast growth factor results in cell transformation and secretion of aberrant forms of the protein.

Basic fibroblast growth factor (bFGF) is a potent mitogen for a wide variety of cell types. Unlike most growth factors, the primary translation product for bFGF appears to lack a secretory signal peptide. To explore the normal mode of bFGF release, as well as to investigate the growth factor's oncogenic potential, expression vectors were created for a bFGF cDNA and for a chimeric molecule in which the bFGF coding sequence was linked to the human growth hormone signal peptide sequence. Transfection of NIH3T3 cells with the bFGF cDNA vectors caused the synthesis of high levels of biologically active, cell-associated bFGF, but no evidence of transformation was detected. In contrast, the chimeric bFGF-signal peptide expression vector induced foci of transformation at a very high frequency. The transformed cells grew in soft agar and were tumorigenic in nude mice. The majority of the immunoreactive bFGF species made by the transformed cells was found in the conditioned medium and appeared to be posttranslationally modified, indicating that the chimeric bFGF-signal peptide molecule was processed through the secretory pathway. The secreted bFGF exhibited little mitogenic activity, suggesting that interaction of bFGF with its receptor likely occurs while the fusion protein is being processed along the secretory pathway.

Animals↗
PubMed1987

Secretion of interleukin-1 by acute myeloblastic leukemia cells in vitro induces endothelial cells to secrete colony stimulating factors.

The interaction of acute myeloblastic leukemia (AML) cells with stromal cells was investigated by adding AML-conditioned media to cultures of human endothelial cells. This conditioned media contained factors that induced expression of both the granulocyte macrophage colony-stimulating factor (GM-CSF) and granulocyte CSF (G-CSF) genes and release of colony stimulating activity from endothelial cells. The conditioned media contained interleukin-1 (IL-1) bioactivity and the endothelial cell stimulatory activity was partially neutralized by anti-IL-1 antiserum. Constitutive expression of the IL-1-beta gene was detected in ten of 17 AML cases analyzed. These results suggest that the unregulated secretion of IL-1 by AML cells can induce stromal cells in vitro to overproduce CSFs. This could contribute to the unrestricted growth of AML cells.

Acute Disease↗
PubMed1981

In vitro gastrin secretion by rat antrum: effects of neurotransmitter agonists, antagonists, and modulators of secretion.

Gastrin release was studied from rat antral mucosal cells maintained under tissue culture conditions. Results of experiments with neurotransmitter agonists, antagonists, and modulators indicate the following: Adrenergic mediation of gastrin release occurs in vitro. Adrenergic stimulatory action could be demonstrated by norepinephrine and, more specifically, beta-receptor activators, whereas an alpha-receptor activator was inhibitory. The effects appear to be specific because the agonists stimulate gastrin release at low concentrations and because these effects are blocked by the appropriate antagonists. Because high carbachol concentrations were needed to produce gastrin secretion, and inhibition by atropine occurred also at high concentrations, these effects may be nonspecific. Both carbachol- and norepinephrine-mediated gastrin release are modified by somatostatin and adenosine. Effective modulation of gastrin release by these substances may be relevant in understanding the fine regulation of gastrin release during digestive processes.

Adenosine↗
PubMed1983

[Comparative cytologic studies of human nasal secretions (differential smears of secretions in patients following laryngectomy and patients with rhinitis sicca in comparison with healthy subjects)].

Using a new method, exfoliative cytologic examinations were performed in patients after laryngectomy and in patients with rhinitis sicca in comparison to normal nasal mucosa. In patients after laryngectomy an increased rate of nasal secretion can be seen. In the nasal smear the main fraction of cells are ciliated epithelial cells. Contrariwise, in patients with rhinitis sicca many squamous epithelial cells can be found. The new method enables the preparation of quantitative cytograms.

Adult↗
PubMed1977

Murine plasma cells secreting more than one class of immunoglobulin heavy chain. II. SAMM 368--a plasmacytoma secreting IgG2b-kappa and IgA-kappa immunoglobulins which do not share idiotypic determinants.

SAMM 368 is a BALB/c plasmacytoma which secretes IgG2b-kappa and IgA-kappa paraproteins. Immunofluorescence studies of ascites cells from the tumor with purified, heavy chain class-specific antiglobulins demonstrate that single cells contain both IgG2 and IgA heavy chains. Idiotypic antisera prepared in mice and rabbits indicate that the two paraproteins produced by the tumor do not share idiotypic determinants. Analysis of the purified paraproteins for allotype markers showed that SAMM 368 IgA bears the BALB/c A12,13,14 determinants. SAMM 368 IgG2b does not carry any detectable allotypic determinants in spite of the fact that heterologous antisera identify the paraprotein as IgG2b.

Amino Acid Sequence↗
PubMed1983

[Evaluation of functional periodicity of the pituitary gland by harmonic analysis.--III Circadian prolactin secretion in subjects with prolactin-secreting adenoma].

The 24-hour periodicity of PRL secretion in 7 prolactinoma subjects of both sexes has been studied by means of the Fourier's harmonic analysis. In all cases elevated PRL titres have been found, that did not show the physiological changes due to sleep and wake. In most of the cases could not be demonstrated either a significant secretory periodicity or secretory episodes occurred with a frequency higher than in the control groups. Such secretory features may depend on changes in the neoplastic cells' receptors for regulating neurotransmitters.

Adenoma↗
PubMed1984

Serotonin-secreting and insulin-secreting ileal carcinoid tumor and the use of in vitro culture of tumoral cells.

The authors report the case of a patient with a typical carcinoid syndrome and a severe hypoglycemia due to hyperinsulinism. He was found to have an ileal carcinoid tumor with hepatic metastasis and no evidence of pancreatic insulinoma at surgery and autopsy. By assaying serotonin and insulin in the tumor and in the supernatants of the culture derived from hepatic metastasis, the authors have been able to show that both hormones were produced by the carcinoid tissue. Cultured cells also synthesized minute amounts of gastrin and thyrocalcitonin.

Blood Glucose↗