Prolactin secretion by mixed ACTH-prolactin pituitary adenoma cells in culture

1985 ◽  
Vol 108 (4) ◽  
pp. 456-463 ◽  
Author(s):  
Tohru Yamaji ◽  
Miyuki Ishibashi ◽  
Akira Teramoto ◽  
Takanori Fukushima
Keyword(s):  
Pituitary Adenoma ◽  
Cultured Cells ◽  
Prolactin Secretion ◽  
Thyrotrophin Releasing Hormone ◽  
Cells In Culture ◽  
Corticotrophin Releasing Factor ◽  
Lysine Vasopressin ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Corticotroph Adenomas

Abstract. To characterize the functional aspect of prolactin (Prl) cells coexisting with corticotroph adenomas, pituitary adenoma cells obtained from a patient with Cushing's disease and a patient with Nelson's syndrome, who were associated with hyperprolactinaemia, were cultured in monolayer and their Prl responses to various secretagogues were compared with those of prolactinoma cells in culture. Immunohistochemistry performed in one of these two adenomas demonstrated the presence of Prl-containing cells in addition to ACTH cells. When ACTH-Prl adenoma cells were exposed to ovine corticotrophin-releasing factor (CRF), a dose-dependent increase in both ACTH and Prl secretion was observed, which was blocked by coincubation with hydrocortisone. In contrast, no stimulatory effect of CRF on Prl release was observed in all of the experiments using prolactinoma cells. Thyrotrophin-releasing hormone, which consistently stimulated Prl secretion in ACTH-Prl adenomas, was effective in triggering Prl release in only 25% of the prolactinomas. Exposure of the cultured cells to lysine vasopressin, growth hormone-releasing factor and vasoactive intestinal peptide resulted in an increase in ACTH and Prl secretion in one ACTH-Prl adenoma, however, none of the prolactinomas responded to these stimuli to secrete Prl. Dopamine and somatostatin, on the other hand, uniformly suppressed Prl secretion from ACTH-Prl adenomas as well as from prolactinoma cells. These results suggest that the mode of Prl secretion by mixed ACTH-Prl pituitary adenomas is not identical to that by pure prolactinomas and is, at least in part, common to that of ACTH secretion.

Serotonin stimulates prolactin secretion in the hypophysectomized adenohypophyseal grafted rat

1983 ◽  
Vol 102 (4) ◽  
pp. 511-516 ◽  
Author(s):  
K. M. Stobie ◽  
S. H. Shin
Keyword(s):  
Prolactin Secretion ◽  
Male Rats ◽  
Normal Male ◽  
Plasma Prolactin ◽  
Site Of Action ◽  
Plasma Prl ◽  
Dose Dependent Increase ◽  
Dose Dependent

Abstract. Normal male, oestrogen (E2) primed male and hypophysectomized adenohypophyseal grafted male rats (HAG rats) were used in the experiments. Serotonin creatinine sulphate was injected as a bolus via an indwelling atrial cannula in the conscious free moving rat. Serotonin caused a dose-dependent increase in plasma prolactin (Prl) in normal (1, 3 and 10 mg/kg serotonin) and E2 primed (1 and 3 mg/kg serotonin) male rats that began immediately after injection and reached a peak within 12–15 min of injection. Oestrogen priming significantly increased the magnitude of the response to serotonin. To analyze the site of action of serotonin in the rat, serotonin (1 mg/kg) was injected into HAG rats. Serotonin increased plasma Prl in this rat preparation, indicating that serotonin acts directly on the ectopic pituitary.

Neonatal testosterone potentiates stimulated prolactin secretion in adult oestrogen-primed rats

1986 ◽  
Vol 109 (1) ◽  
pp. 57-60 ◽  
Author(s):  
R. G. Dyer ◽  
S. Mansfield
Keyword(s):  
Testosterone Propionate ◽  
Prolactin Secretion ◽  
Female Rats ◽  
Neonatal Exposure ◽  
Adult Rats ◽  
Blood Samples ◽  
Before And After ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Stimulation Of

ABSTRACT Blood samples were collected from oestrogen-primed gonadectomized adult rats before and after electrical stimulation of the preoptic part of the hypothalamus. Six groups of rats were used for the experiments. These were (a) males castrated on the first day of life, (b) males castrated after puberty, (c) females ovariectomized after puberty and (d), (e) and (f) females given testosterone propionate at birth (1·25, 0·125 and 0·0125 mg/rat respectively). Neonatal exposure of the female rats to testosterone caused a dose-dependent increase in the amounts of prolactin released to levels significantly (P<0·01) higher than those observed in male animals and in untreated females. The results indicate that although neonatal testosterone inhibits oestrogen-stimulated prolactin secretion in adult rats, the neuroendocrine apparatus controlling secretion of the hormone is capable of being activated to greater effect after exposure to androgens at the time of birth. J. Endocr. (1986) 109, 57–60

Met-enkephalin stimulates secretion of ACTH in sheep

1986 ◽  
Vol 111 (3) ◽  
pp. 463-467 ◽  
Author(s):  
X.-M. Wang ◽  
J. P. Coghlan ◽  
M. Congiu ◽  
B. A. Scoggins ◽  
E. M. Wintour
Keyword(s):  
Opioid Peptides ◽  
Plasma Concentrations ◽  
Combined Effect ◽  
Corticotrophin Releasing Factor ◽  
Conscious Sheep ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Acth Release

ABSTRACT The ability of opioid peptides to affect plasma immunoreactive ACTH concentrations was examined in conscious sheep. Plasma concentrations of ACTH were significantly increased by an i.v. infusion of Met-enkephalin and its analogue (FK-33824). There was a dose-dependent increase in plasma concentrations of ACTH with a graded administration of FK-33824. The combined effect of Met-enkephalin and ovine corticotrophin-releasing factor (oCRF) or FK-33824 and oCRF on plasma concentrations of ACTH was greater than the effect of each peptide when given individually. This study demonstrates that Met-enkephalin and its analogue stimulate ACTH release in sheep. J. Endocr. (1986) 111, 463–467

Increased Expression of u-PA and u-PAR on Monocytes by LDL and Lp(a) Lipoproteins – Consequences for Plasmin Generation and Monocyte Adhesion

1999 ◽  
Vol 81 (04) ◽  
pp. 594-560 ◽  
Author(s):  
Florence Ganné ◽  
Marc Vasse ◽  
Jean-Louis Beaudeu ◽  
Jacqueline Peynet ◽  
Arnaud François ◽  
...  
Keyword(s):  
Fold Increase ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Atheromatous Plaque ◽  
Monocyte Adhesion ◽  
Blood Monocytes ◽  
Proteolytic Cascade ◽  
Ecm Degradation ◽  
Dose Dependent Increase ◽  
Dose Dependent

SummaryMonocyte-derived foam cells figure prominently in rupture-prone regions of atherosclerotic plaque. As urokinase/urokinase-receptor (u-PA/u-PAR) is the trigger of a proteolytic cascade responsible for ECM degradation, we have examined the effect of atherogenic lipoproteins on monocyte surface expression of u-PAR and u-PA. Peripheral blood monocytes, isolated from 10 healthy volunteers, were incubated with 10 to 200 µg/ml of native or oxidised (ox-) atherogenous lipoproteins for 18 h and cell surface expression of u-PA and u-PAR was analysed by flow cytometry. Both LDL and Lp(a) induced a dose-dependent increase in u-PA (1.6-fold increase with 200 μg/ml of ox-LDL) and u-PAR [1.7-fold increase with 200 μg/ml of ox-Lp(a)]. There is a great variability of the response among the donors, some of them remaining non-responders (absence of increase of u-PA or u-PAR) even at 200 μg/ml of lipoproteins. In positive responders, enhanced u-PA/u-PAR is associated with a significant increase of plasmin generation (1.9-fold increase with 200 μg/ml of ox-LDL), as determined by an amidolytic assay. Furthermore, monocyte adhesion to vitronectin and fibrinogen was significantly enhanced by the lipoproteins [respectively 2-fold and 1.7-fold increase with 200 μg/ml of ox-Lp(a)], due to the increase of u-PAR and ICAM-1, which are receptors for vitronectin and fibrinogen. These data suggest that atherogenous lipoproteins could contribute to the development of atheromatous plaque by increasing monocyte adhesion and trigger plaque weakening by inducing ECM degradation.

LH-RH TEST IN 100 PATIENTS WITH OVARIAN INSUFFICIENCY

1974 ◽  
Vol 75 (3) ◽  
pp. 428-434 ◽  
Author(s):  
P.-J. Czygan ◽  
M. Breckwoldt ◽  
F. Lehmann ◽  
R. Langefeld ◽  
G. Bettendorf
Keyword(s):  
Intravenous Injection ◽  
Functional State ◽  
Clear Correlation ◽  
Normal Range ◽  
Ovarian Insufficiency ◽  
Lh Rh ◽  
Dose Dependent Increase ◽  
Dose Dependent

ABSTRACT The effect of synthetic LH-RH was studied in 100 patients with various types of ovarian insufficiency by following up the FSH- and LH-levels in plasma. LH-RH was administered in doses of 12.5, 25 and 100 μg as a rapid intravenous injection. The patients were classified according to the endocrine state of the pituitary as evidenced by the urinary gonadotrophin levels. A clear correlation between the functional state of the pituitary and its responsiveness to exogenous LH-RH was demonstrated. Most of the patients with undetectable low urinary gonadotrophin levels failed to respond. The majority of patients with gonadotrophin excretion in the normal range and those with elevated levels reacted with a dose dependent increase in circulating LH. The amount of liberated FSH however was related to the injected dose only in patients with high gonadotrophic excretion. The present study indicates that synthetic LH-RH provides a useful tool in the evaluation of the pitutiary function particularly in patients with low and with undetectable gonadotrophin excretion. The data presented in this paper also demonstrate that the functional state of the pituitary is clearly reflected by the urinary gonadotrophin levels.

Evaluation of the Laxative activity of Saponin Enriched Hydroethanolic Pericarp extract of Sapindus emarginatus in Animal models

2020 ◽  
Vol 16 ◽  
Author(s):  
Lalitha Vivekanandan ◽  
Roxanne Gekonge Mandere ◽  
Sivakumar Thangavel
Keyword(s):  
Animal Models ◽  
Gravimetric Analysis ◽  
Triterpene Saponins ◽  
Laxative Effect ◽  
Saponin Content ◽  
The Family ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Efficacious Drug

Background: Constipation is a common, predominant, chronic gastrointestinal functional disorder. The drugs available to treat constipation are limited because of their side effects in long term use. So we need of efficacious drug to treat constipation. Sapindus emarginatus Vahl belongs to the family Sapindaceae, commonly known as soapnut. Traditionally used for the antipruritic, antifertility, constipation, and anti-inflammatory agents. Objective: The present study was undertaken to evaluate the laxative activity of hydroethanolic pericarp extract of Sapindus emarginatus (HESE) in animal models. Methods: The saponin content in extract was measured by gravimetric analysis. The laxative activity of hydroethanolic pericarp extract of Sapindus emarginatus is evaluated by the weight of feces matter, charcoal meal hyperperistalsis test, and loperamide induced constipation model. Results: The saponin content of the soapnut pericarp was 13.48 % and the extract was found to be 11.92 %. The results obtained from these models showed a significant dose-dependent increase in fecal weight, peristalsis index, and moisture content compared to control animals. Conclusion: The present study concluded that the oral administration of HESE showed a significant laxative activity by using different animal models. The presence of triterpene saponins is responsible for this activity. Further studies are needed to confirm their mechanism behind the laxative effect. The administration of extract was found to be a valid candidate in constipation therapy.

scholarly journals Morphological and Behavioral Effects in Zebrafish Embryos after Exposure to Smoke Dyes

Toxics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Kimberly T. To ◽  
Lindsey St. Mary ◽  
Allyson H. Wooley ◽  
Mitchell S. Wilbanks ◽  
Anthony J. Bednar ◽  
...  
Keyword(s):  
Dose Dependence ◽  
Behavioral Effects ◽  
Zebrafish Embryos ◽  
Comprehensive Understanding ◽  
Anthraquinone Dyes ◽  
Locomotor Movement ◽  
Different Types ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Significant Mortality

Solvent Violet 47 (SV47) and Disperse Blue 14 (DB14) are two anthraquinone dyes that were previously used in different formulations for the production of violet-colored smoke. Both dyes have shown potential for toxicity; however, there is no comprehensive understanding of their effects. Zebrafish embryos were exposed to SV47 or DB14 from 6 to 120 h post fertilization (hpf) to assess the dyes’ potential adverse effects on developing embryos. The potential ability of both dyes to cross the blood–brain barrier was also assessed. At concentrations between 0.55 and 5.23 mg/L, SV47 showed a dose-dependent increase in mortality, jaw malformation, axis curvature, and edemas. At concentrations between 0.15 and 7.54 mg/L, DB14 did not have this same dose-dependence but had similar morphological outcomes at the highest doses. Nevertheless, while SV47 showed significant mortality from 4.20 mg/L, there was no significant mortality on embryos exposed to DB14. Regardless, decreased locomotor movement was observed at all concentrations of DB14, suggesting an adverse neurodevelopmental effect. Overall, our results showed that at similar concentrations, SV47 and DB14 caused different types of phenotypic effects in zebrafish embryos.

Role of extracellular calcium and calmodulin in prolactin secretion induced by hyposmolarity, thyrotropin-releasing hormone, and high K+ in GH4C1 cells

1990 ◽  
Vol 123 (2) ◽  
pp. 218-224 ◽  
Author(s):  
Xiangbing Wang ◽  
Noriyuki Sato ◽  
Monte A. Greer ◽  
Susan E. Greer ◽  
Staci McAdams
Keyword(s):  
Smooth Muscle ◽  
Muscle Relaxant ◽  
Prolactin Secretion ◽  
Thyrotropin Releasing Hormone ◽  
Dependent Manner ◽  
Cell Toxicity ◽  
High K ◽  
Dose Dependent ◽  
Smooth Muscle Relaxant

Abstract. The mechanism by which 30% medium hyposmolarity induces PRL secretion by GH4C1 cells was compared with that induced by 100 nmol/l TRH or 30 mmol/l K+. Removing medium Ca2+, blocking Ca2+ channels with 50 μmol/l verapamil, or inhibiting calmodulin activation with 20 μmol/l trifluoperazine, 10 μmol/l chlorpromazine or 10 μmol/l pimozide almost completely blocked hyposmolarity-induced secretion. The smooth muscle relaxant, W-7, which is believed relatively specific in inhibiting the Ca2+-calmodulin interaction, depressed hyposmolarity-induced PRL secretion in a dose-dependent manner (r = −0.991, p<0.01 ). The above drugs also blocked or decreased high K+-induced secretion, but had much less effect on TRH-induced secretion. Secretion induced by TRH, hyposmolarity, or high K+ was optimal at pH 7.3-7.65 and was significantly depressed at pH 6.0 or 8.0, indicating that release of hormone induced by all 3 stimuli is due to an active cell process requiring a physiologic extracellular pH and is not produced by nonspecific cell toxicity. The data suggest hyposmolarity and high K+ may share some similarities in their mechanism of stimulating secretion, which is different from that of TRH.

Increased Urinary Excretion of Carnitine and Acylcarnitine by Mercuric Chloride Is Reversed by 2,3-Dimercapto-1-Propanesulfonic Acid in Rats

2010 ◽  
Vol 29 (3) ◽  
pp. 313-317
Author(s):  
Waleed A. Al-Madani ◽  
Nikhat J. Siddiqi ◽  
Abdullah S. Alhomida ◽  
Haseeb A. Khan ◽  
Ibrahim A. Arif ◽  
...  
Keyword(s):  
Body Weight ◽  
Urinary Excretion ◽  
Mercuric Chloride ◽  
Free Carnitine ◽  
Male Rats ◽  
Significant Protection ◽  
Total Carnitine ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
Wistar Male Rats

This investigation was aimed to study the effect of 2,3-dimercapto-1-propanesulfonic acid (DMPS) on mercuric chloride (HgCl2)-induced alterations in urinary excretion of various carnitine fractions including free carnitine (FC), acylcarnitine (AC), and total carnitine (TC). Different groups of Wistar male rats were treated with HgCl2 at the doses of 0.1, 0.5, 1.0, 2.0, and 3.0 mg/kg body weight, and the animals were sacrificed at 24 hours following HgCl2 injection. A separate batch of animals received HgCl2 (2 mg/kg) with or without DMPS (100 mg/kg) and sacrificed at 24 or 48 hours after dosing. Administration of HgCl2 resulted in statistically significant and dose-dependent increase in the urinary excretion of FC, AC, and TC in rats. However, the ratio of urinary AC:FC was significantly decreased by HgCl2. Pretreatment with DMPS offered statistically significant protection against HgCl2-induced alterations in various urinary carnitine fractions in rats.

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