Possible Direct Effect of Serotonin on Pituitary Prolactin Secretion: in vivo and in vitro Studies

1987 ◽  
Vol 25 (3) ◽  
pp. 160-170 ◽  
Author(s):  
F. López ◽  
D. González ◽  
E. Aguilar
Keyword(s):  
Direct Effect ◽  
Prolactin Secretion ◽  
In Vitro Studies ◽  
Pituitary Prolactin

scholarly journals MON-LB60 Prolactin Response to Metformin in Cabergoline-Resistant Prolactinomas: A Prospective Study

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Luiz Henrique Corrêa Portari ◽  
Silvia Regina Correa-Silva ◽  
Julio Abucham
Keyword(s):  
Extended Release ◽  
Prolactin Secretion ◽  
In Vitro Studies ◽  
Metformin Treatment ◽  
Fasting Glycemia ◽  
Prolactin Response ◽  
A Prospective Study

Abstract Introduction: Prolactinomas are the most frequent pituitary-secreting tumors. Medical therapy with cabergoline (CAB), a dopamine agonist (DA), is the first line treatment, but 10% of prolactinomas are resistant to CAB. Recently, in vitro studies have shown anti-tumoral activity of metformin and other biguanids in human prolactinomas1, which prompted us to investigate that possibility in vivo. Aim: To evaluate the effect of metformin (MET) on Prolactin (PRL) secretion in patients with CAB resistant prolactinomas. Design and Setting: Prospective interventional study in a single referral center. Subjects: Ten patients (7 M; mean age: 44 ± 12y) with CAB resistant (PRL: 148 ± 125ng/ml; range: 38 - 386) prolactinomas (all macroadenomas) and metabolic syndrome on maximally tolerated CAB doses (4.3 ± 1.2 mg/week; range: 2.0-7.0) for ≥ 6 months (45 ± 39mo; range: 6-120). Intervention: Oral extended release metformin (p.o.) was prescribed according to patient’s tolerance (mean dose: 1.3 ± 0.4 g; range: 1.0-2.0). Main Outcome Measurements: Serum PRL (Elecsys, Roche, Indianapolis, USA), body weight (BW), fasting glycemia (FG) and HbA1C were evaluated before and at two time points during metformin treatment (30-60 and 120-180 days). Results: BW, FG, and/or HbA1C reductions were observed in 9/10 patients and mean FG decreased significantly (P=0.04). No significant changes were observed in serum PRL levels during metformin treatment [134 ± 124 ng/ml vs 138 ± 132 ng/ml vs 144 ± 129 ng/ml, before, at 30-60 days and at 120-180 days, respectively (P=0.499, mixed-effects analysis with the Geisser-Greenhouse correction)]. Individually, two patients exhibited a ≥ 50% decrease in PRL levels at a single timepoint (one at 30-60 days, with a further increase at 120-180 days and the other at 120-180 days). Conclusion: Metformin, at usual doses, did not inhibit prolactin secretion in patients with cabergoline-resistant prolactinomas. The discrepancy between our results and in vitro studies is not clear, but may be related to the much higher concentrations of metformin used in vitro1 as compared to the serum concentrations observed in patients during metformin treatment2. References: 1Gao J et al. Metformin inhibits growth and prolactin secretion of pituitary prolactinoma cells and xenografts. J Cell Mol Med. 2018 22:6368-79; 2 Frid A et al. Novel assay of metformin levels in patients with type 2 diabetes and varying levels of renal function: clinical recommendations. Diabetes Care 2010 33:1291-3.

Superoxide, Xanthine Oxidase and Platelet Reactions: Further Studies on Mechanisms by which Oxidants Influence Platelets

1981 ◽  
Vol 45 (03) ◽  
pp. 290-293 ◽  
Author(s):  
Peter H Levine ◽  
Danielle G Sladdin ◽  
Norman I Krinsky
Keyword(s):  
Superoxide Dismutase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Direct Effect ◽  
Platelet Function ◽  
Experimental Conditions ◽  
Release Reaction

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

The Venom of the Boomslang (Dispholidus Typus): In Vivo and in Vitro Studies

1969 ◽  
Vol 21 (02) ◽  
pp. 234-244 ◽  
Author(s):  
N Mackay ◽  
J.C Ferguson ◽  
Antonia Bagshawe ◽  
A.T.T Forrester ◽  
G.P Mcnicol
Keyword(s):  
In Vitro Studies

SummaryAn account is given of the effects of boomslang venom in man. Evidence was found of a fibrinolytic state apparently secondary to the coagulant action of the venom. These features rapidly responded to the administration of specific antivenom. In vitro studies, using a homogenate of boomslang parotids, confirmed the coagulant properties of the venom and showed them to be of much greater potency than the proteolytic actions.

Effect of X-irradiation on gene expression of rat liver chemokines: in vivo and in vitro studies

2008 ◽  
Vol 46 (01) ◽  
Author(s):  
F Moriconi ◽  
H Christiansen ◽  
H Christiansen ◽  
N Sheikh ◽  
J Dudas ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rat Liver ◽  
In Vitro Studies ◽  
X Irradiation

Ciamexon in low-dose streptozotocin induced diabetes mellitus. In vivo and in vitro studies

1986 ◽  
Vol 113 (1_Suppl) ◽  
pp. S120-S121
Author(s):  
TH. LINN ◽  
H. GERMANN ◽  
B. HERING ◽  
R. BRETZEL ◽  
K. FEDERLIN
Keyword(s):  
Diabetes Mellitus ◽  
Low Dose ◽  
In Vitro Studies ◽  
Streptozotocin Induced Diabetes

Delayed hypersensitivity to tetanus toxoid in man: in vivo and in vitro studies

Pathology ◽  
1983 ◽  
Vol 15 (4) ◽  
pp. 369-372 ◽  
Author(s):  
Christine Johnson ◽  
R.S. Walls ◽  
A. Ruwoldt
Keyword(s):  
Tetanus Toxoid ◽  
In Vitro Studies ◽  
Delayed Hypersensitivity

Transplantation of Adipose-derived Cells for Periodontal Regeneration: A Systematic Review

2019 ◽  
Vol 14 (6) ◽  
pp. 504-518 ◽  
Author(s):  
Dilcele Silva Moreira Dziedzic ◽  
Bassam Felipe Mogharbel ◽  
Priscila Elias Ferreira ◽  
Ana Carolina Irioda ◽  
Katherine Athayde Teixeira de Carvalho
Keyword(s):  
Systematic Review ◽  
Animal Models ◽  
Platelet Rich Plasma ◽  
Periodontal Regeneration ◽  
In Vitro Studies ◽  
In Vivo Studies ◽  
Cell Sources ◽  
Study Designs

This systematic review evaluated the transplantation of cells derived from adipose tissue for applications in dentistry. SCOPUS, PUBMED and LILACS databases were searched for in vitro studies and pre-clinical animal model studies using the keywords “ADIPOSE”, “CELLS”, and “PERIODONTAL”, with the Boolean operator “AND”. A total of 160 titles and abstracts were identified, and 29 publications met the inclusion criteria, 14 in vitro and 15 in vivo studies. In vitro studies demonstrated that adipose- derived cells stimulate neovascularization, have osteogenic and odontogenic potential; besides adhesion, proliferation and differentiation on probable cell carriers. Preclinical studies described improvement of bone and periodontal healing with the association of adipose-derived cells and the carrier materials tested: Platelet Rich Plasma, Fibrin, Collagen and Synthetic polymer. There is evidence from the current in vitro and in vivo data indicating that adipose-derived cells may contribute to bone and periodontal regeneration. The small quantity of studies and the large variation on study designs, from animal models, cell sources and defect morphology, did not favor a meta-analysis. Additional studies need to be conducted to investigate the regeneration variability and the mechanisms of cell participation in the processes. An overview of animal models, cell sources, and scaffolds, as well as new perspectives are provided for future bone and periodontal regeneration study designs.

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