FURTHER STUDIES ON HYPOTHALAMIC-PITUITARY-TESTICULAR FUNCTION IN OLD RATS

1979 ◽  
Vol 92 (2) ◽  
pp. 358-369 ◽  
Author(s):  
Karl M. Pirke ◽  
Beate Krings ◽  
Hermann-J. Vogt
Keyword(s):  
Old Age ◽  
Plasma Concentrations ◽  
Biologically Active ◽  
Repeated Injection ◽  
Lh Receptor ◽  
Male Wistar Rats ◽  
Old Rats ◽  
Lh Rh

ABSTRACT The dysfunction of the hypothalamic-pituitary-gonadal axis in old age was studied in 24-month old male Wistar rats which were compared with 3-month old animals. The hypothalamic LH-RH content and the pituitary LH were significantly lower in the old than in the young adult animals. The plasma concentrations of LH and testosterone were significantly higher in the young rats. The primary cause of these age-dependent changes probably is a hypothalamic dysfunction. When isolated Leydig cells of young and old rats were incubated in vitro, the testosterone secretion per cell was significantly smaller in old than in young cells with as well as without HCG stimulation. In vivo stimulation of rats by iv injection of biologically active iodinated hCG revealed that the intratesticular uptake of the gonadotrophin was not different in young and old rats. The testosterone response, however, was significantly reduced in old age. An in vitro "desensitisation" experiment in which the LH receptor capacity was artificially reduced demonstrated that the 40 % reduction of receptor capacity in old testes as described earlier will not impair the testicular uptake of gonadotrophin from blood. Repeated injection of hCG results in equally elevated testosterone concentrations in young and old rats.

Peripheral metabolism of [35S]parathyroid hormone in vivo: influence of alterations in calcium availability and parathyroid status

1989 ◽  
Vol 122 (1) ◽  
pp. 237-245 ◽  
Author(s):  
F. R. Bringhurst ◽  
A. M. Stern ◽  
M. Yotts ◽  
N. Mizrahi ◽  
G. V. Segre ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Plasma Concentrations ◽  
Biologically Active ◽  
High Calcium Intake ◽  
Amino Terminal ◽  
High Calcium ◽  
Calcium Availability ◽  
Peripheral Metabolism

ABSTRACT Parathyroid hormone (PTH) is rapidly metabolized, mainly by liver and kidney, to smaller fragments that are believed to be biologically inactive. The significance of this peripheral metabolism in the overall actions of PTH is unclear. Generation of circulating biologically active amino-terminal PTH fragments during metabolism in vivo has been suggested by certain observations in vitro, and what are believed to be amino-terminal fragments may be detectable in blood under pathological circumstances in vivo (such as renal failure and coexistent hyperparathyroidism) when highly sensitive assays are employed. We recently reported, however, that administration to normal rats of [35S]bovine PTH ([35S]bPTH) directly labelled at amino-terminal methionines, followed by high-resolution chromatographic analysis of extracted [35S]peptides, does not result in appearance of radioactive amino-terminal fragments in blood, even when the tracer is continuously infused to near-physiological plasma concentrations. We have now employed these techniques to address a second question regarding hormonal metabolism: is hormonal metabolism modified during metabolic perturbations such as changing calcium availability or altered levels of calciotrophic hormones? Metabolism of [35S-Met]bPTH (900 Ci/mmol), either alone or together with [3H-Pro]bPTH, however, did riot lead to alterations in the rate of hormonal clearance nor to detectable circulating amino-terminal fragments, either in calcium-deprived or thyroparathyroidectomized rats or when animals were first rendered intoxicated with vitamin D or maintained on a high calcium intake. Likewise, tissue localization and specific cleavage patterns of intact hormone in liver or kidney were all unaltered by these various manoeuvres. We conclude that regulation of peripheral metabolism of PTH does not exert important physiological control over the concentration of circulating biologically active PTH and that active amino-terminal fragments of the hormone are not released into blood even under circumstances of calcium deprivation or hypocalcaemia. Journal of Endocrinology (1989) 122, 237–245

Comparison of Specific Antibody, D-Phe-Pro-Arg-CH2Cl and Aprotinin for Prevention of In Vitro Effects of Recombinant Tissue-Type Plasminogen Activator on Haemostasis Parameters

1987 ◽  
Vol 58 (03) ◽  
pp. 921-926 ◽  
Author(s):  
E Seifried ◽  
P Tanswell
Keyword(s):  
Specific Antibody ◽  
Plasma Concentrations ◽  
Fibrinolytic Therapy ◽  
Tissue Type ◽  
Control Value ◽  
Type Plasminogen Activator ◽  
In Vitro Effects ◽  
Fibrinolytic Parameters

SummaryIn vitro, concentration-dependent effects of rt-PA on a range of coagulation and fibrinolytic assays in thawed plasma samples were investigated. In absence of a fibrinolytic inhibitor, 2 μg rt-PA/ml blood (3.4 μg/ml plasma) caused prolongation of clotting time assays and decreases of plasminogen (to 44% of the control value), fibrinogen (to 27%), α2-antiplasmin (to 5%), FV (to 67%), FVIII (to 41%) and FXIII (to 16%).Of three inhibitors tested, a specific polyclonal anti-rt-PA antibody prevented interferences in all fibrinolytic and most clotting assays. D-Phe-Pro-Arg-CH2Cl (PPACK) enabled correct assays of fibrinogen and fibrinolytic parameters but interfered with coagulometric assays dependent on endogenous thrombin generation. Aprotinin was suitable only for a restricted range of both assay types.Most in vitro effects were observed only with rt-PA plasma concentrations in excess of therapeutic values. Nevertheless it is concluded that for clinical application, collection of blood samples on either specific antibody or PPACK is essential for a correct assessment of in vivo effects of rt-PA on the haemostatic system in patients undergoing fibrinolytic therapy.

Metabolomics of Healthy Berry Fruits

2019 ◽  
Vol 25 (37) ◽  
pp. 4888-4902 ◽  
Author(s):  
Gilda D'Urso ◽  
Sonia Piacente ◽  
Cosimo Pizza ◽  
Paola Montoro
Keyword(s):  
Biological Activities ◽  
Biologically Active ◽  
In Vivo Studies ◽  
Bioactive Metabolites ◽  
Active Metabolites ◽  
Positive Effects ◽  
Cell Functions ◽  
Berry Fruits

The consumption of berry-type fruits has become very popular in recent years because of their positive effects on human health. Berries are in fact widely known for their health-promoting benefits, including prevention of chronic disease, cardiovascular disease and cancer. Berries are a rich source of bioactive metabolites, such as vitamins, minerals, and phenolic compounds, mainly anthocyanins. Numerous in vitro and in vivo studies recognized the health effects of berries and their function as bioactive modulators of various cell functions associated with oxidative stress. Plants have one of the largest metabolome databases, with over 1200 papers on plant metabolomics published only in the last decade. Mass spectrometry (MS) and NMR (Nuclear Magnetic Resonance) are the most important analytical technologies on which the emerging ''omics'' approaches are based. They may provide detection and quantization of thousands of biologically active metabolites from a tissue, working in a ''global'' or ''targeted'' manner, down to ultra-trace levels. In the present review, we highlighted the use of MS and NMR-based strategies and Multivariate Data Analysis for the valorization of berries known for their biological activities, important as food and often used in the preparation of nutraceutical formulations.

Design, Synthesis, and Pharmacokinetic Evaluation of O-Carbamoyl Tizoxanide Prodrugs

2020 ◽  
Vol 16 ◽  
Author(s):  
Xi He ◽  
Wenjun Hu ◽  
Fanhua Meng ◽  
Xingzhou Li
Keyword(s):  
Plasma Concentration ◽  
Broad Spectrum ◽  
Plasma Concentrations ◽  
Antiviral Drug ◽  
Systemic Exposure ◽  
Pharmacokinetic Profile ◽  
Hydroxyl Group ◽  
First Pass

Background: The broad-spectrum antiparasitic drug nitazoxanide (N) has been repositioned as a broad-spectrum antiviral drug. Nitazoxanide’s in vivo antiviral activities are mainly attributed to its metabolitetizoxanide, the deacetylation product of nitazoxanide. In reference to the pharmacokinetic profile of nitazoxanide, we proposed the hypotheses that the low plasma concentrations and the low system exposure of tizoxanide after dosing with nitazoxanide result from significant first pass effects in the liver. It was thought that this may be due to the unstable acyloxy bond of nitazoxanide. Objective: Tizoxanide prodrugs, with the more stable formamyl substituent attached to the hydroxyl group rather than the acetyl group of nitazoxanide, were designed with the thought that they might be more stable in plasma. It was anticipated that these prodrugs might be less affected by the first pass effect, which would improve plasma concentrations and system exposure of tizoxanide. Method: These O-carbamoyl tizoxanide prodrugs were synthesized and evaluated in a mouse model for pharmacokinetic (PK) properties and in an in vitro model for plasma stabilities. Results: The results indicated that the plasma concentration and the systemic exposure of tizoxanide (T) after oral administration of O-carbamoyl tizoxanide prodrugs were much greater than that produced by equimolar dosage of nitazoxanide. It was also found that the plasma concentration and the systemic exposure of tizoxanide glucuronide (TG) were much lower than that produced by nitazoxanide. Conclusion: Further analysis showed that the suitable plasma stability of O-carbamoyl tizoxanide prodrugs is the key factor in maximizing the plasma concentration and the systemic exposure of the active ingredient tizoxanide.

Phytochemical, Analytical and Medicinal Studies of Holoptelea integrifolia Roxb. Planch - A Review

2019 ◽  
Vol 5 (4) ◽  
pp. 270-277 ◽  
Author(s):  
Vijay Kumar ◽  
Simranjeet Singh ◽  
Ragini Bhadouria ◽  
Ravindra Singh ◽  
Om Prakash
Keyword(s):  
Liquid Chromatography ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
High Performance ◽  
Biologically Active ◽  
Toxicological Studies ◽  
Wide Range ◽  
Layer Chromatography

Holoptelea integrifolia Roxb. Planch (HI) has been used to treat various ailments including obesity, osteoarthritis, arthritis, inflammation, anemia, diabetes etc. To review the major phytochemicals and medicinal properties of HI, exhaustive bibliographic research was designed by means of various scientific search engines and databases. Only 12 phytochemicals have been reported including biologically active compounds like betulin, betulinic acid, epifriedlin, octacosanol, Friedlin, Holoptelin-A and Holoptelin-B. Analytical methods including the Thin Layer Chromatography (TLC), High-Performance Thin Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography With Mass Spectral (LC-MS) analysis have been used to analyze the HI. From medicinal potency point of view, these phytochemicals have a wide range of pharmacological activities such as antioxidant, antibacterial, anti-inflammatory, and anti-tumor. In the current review, it has been noticed that the mechanism of action of HI with biomolecules has not been fully explored. Pharmacology and toxicological studies are very few. This seems a huge literature gap to be fulfilled through the detailed in-vivo and in-vitro studies.

scholarly journals An In Vivo Predictive Dissolution Methodology (iPD Methodology) with a BCS Class IIb Drug Can Predict the In Vivo Bioequivalence Results: Etoricoxib Products

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 507
Author(s):  
Isabel Gonzalez-Alvarez ◽  
Marival Bermejo ◽  
Yasuhiro Tsume ◽  
Alejandro Ruiz-Picazo ◽  
Marta Gonzalez-Alvarez ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
In Vitro Dissolution ◽  
Case Examples ◽  
Dissolution Studies ◽  
Weak Bases ◽  
Transit Times ◽  
Class Iib ◽  
The Impact

The purpose of this study was to predict in vivo performance of three oral products of Etoricoxib (Arcoxia® as reference and two generic formulations in development) by conducting in vivo predictive dissolution with GIS (Gastro Intestinal Simulator) and computational analysis. Those predictions were compared with the results from previous bioequivalence (BE) human studies. Product dissolution studies were performed using a computer-controlled multicompartmental dissolution device (GIS) equipped with three dissolution chambers, representing stomach, duodenum, and jejunum, with integrated transit times and secretion rates. The measured dissolved amounts were modelled in each compartment with a set of differential equations representing transit, dissolution, and precipitation processes. The observed drug concentration by in vitro dissolution studies were directly convoluted with permeability and disposition parameters from literature to generate the predicted plasma concentrations. The GIS was able to detect the dissolution differences among reference and generic formulations in the gastric chamber where the drug solubility is high (pH 2) while the USP 2 standard dissolution test at pH 2 did not show any difference. Therefore, the current study confirms the importance of multicompartmental dissolution testing for weak bases as observed for other case examples but also the impact of excipients on duodenal and jejunal in vivo behavior.

scholarly journals Plant Extracts and Reactive Oxygen Species as Two Counteracting Agents with Anti- and Pro-Obesity Properties

2019 ◽  
Vol 20 (18) ◽  
pp. 4556 ◽  
Author(s):  
Hanna Zielinska-Blizniewska ◽  
Przemyslaw Sitarek ◽  
Anna Merecz-Sadowska ◽  
Katarzyna Malinowska ◽  
Karolina Zajdel ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Plant Extracts ◽  
Complex Disease ◽  
Reactive Oxygen ◽  
Complementary Therapy ◽  
Biologically Active ◽  
Mitochondrial Activity ◽  
Oxygen Species

Obesity is a complex disease of great public health significance worldwide: It entails several complications including diabetes mellitus type 2, cardiovascular dysfunction and hypertension, and its prevalence is increasing around the world. The pathogenesis of obesity is closely related to reactive oxygen species. The role of reactive oxygen species as regulatory factors in mitochondrial activity in obese subjects, molecules taking part in inflammation processes linked to excessive size and number of adipocytes, and as agents governing the energy balance in hypothalamus neurons has been examined. Phytotherapy is the traditional form of treating health problems using plant-derived medications. Some plant extracts are known to act as anti-obesity agents and have been screened in in vitro models based on the inhibition of lipid accumulation in 3T3-L1 cells and activity of pancreatic lipase methods and in in vivo high-fat diet-induced obesity rat/mouse models and human models. Plant products may be a good natural alternative for weight management and a source of numerous biologically-active chemicals, including antioxidant polyphenols that can counteract the oxidative stress associated with obesity. This review presents polyphenols as natural complementary therapy, and a good nutritional strategy, for treating obesity without serious side effects.

scholarly journals Internal exposure dynamics drive the Adverse Outcome Pathways of synthetic glucocorticoids in fish

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Luigi Margiotta-Casaluci ◽  
Stewart F. Owen ◽  
Belinda Huerta ◽  
Sara Rodríguez-Mozaz ◽  
Subramanian Kugathas ◽  
...  
Keyword(s):  
Predictive Power ◽  
Adverse Outcome ◽  
Plasma Concentrations ◽  
Internal Exposure ◽  
Adverse Outcome Pathway ◽  
Conceptual Tool ◽  
Fish Model ◽  
Species Specific

Abstract The Adverse Outcome Pathway (AOP) framework represents a valuable conceptual tool to systematically integrate existing toxicological knowledge from a mechanistic perspective to facilitate predictions of chemical-induced effects across species. However, its application for decision-making requires the transition from qualitative to quantitative AOP (qAOP). Here we used a fish model and the synthetic glucocorticoid beclomethasone dipropionate (BDP) to investigate the role of chemical-specific properties, pharmacokinetics, and internal exposure dynamics in the development of qAOPs. We generated a qAOP network based on drug plasma concentrations and focused on immunodepression, skin androgenisation, disruption of gluconeogenesis and reproductive performance. We showed that internal exposure dynamics and chemical-specific properties influence the development of qAOPs and their predictive power. Comparing the effects of two different glucocorticoids, we highlight how relatively similar in vitro hazard-based indicators can lead to different in vivo risk. This discrepancy can be predicted by their different uptake potential, pharmacokinetic (PK) and pharmacodynamic (PD) profiles. We recommend that the development phase of qAOPs should include the application of species-specific uptake and physiologically-based PK/PD models. This integration will significantly enhance the predictive power, enabling a more accurate assessment of the risk and the reliable transferability of qAOPs across chemicals.

scholarly journals In vitro analysis of the origin and maintenance of O-2Aadult progenitor cells.

1992 ◽  
Vol 116 (1) ◽  
pp. 167-176 ◽  
Author(s):  
D Wren ◽  
G Wolswijk ◽  
M Noble
Keyword(s):  
Adult Life ◽  
Cell Types ◽  
Adult Rats ◽  
Optic Nerves ◽  
Limited Life ◽  
Old Rats ◽  
Vitro Analysis

We have been studying the differing characteristics of oligodendrocyte-type-2 astrocyte (O-2A) progenitors isolated from optic nerves of perinatal and adult rats. These two cell types display striking differences in their in vitro phenotypes. In addition, the O-2Aperinatal progenitor population appears to have a limited life-span in vivo, while O-2Aadult progenitors appear to be maintained throughout life. O-2Aperinatal progenitors seem to have largely disappeared from the optic nerve by 1 mo after birth, and are not detectable in cultures derived from optic nerves of adult rats. In contrast, O-2Aadult progenitors can first be isolated from optic nerves of 7-d-old rats and are still present in optic nerves of 1-yr-old rats. These observations raise two questions: (a) From what source do O-2Aadult progenitors originate; and (b) how is the O-2Aadult progenitor population maintained in the nerve throughout life? We now provide in vitro evidence indicating that O-2Aadult progenitors are derived directly from a subpopulation of O-2Aperinatal progenitors. We also provide evidence indicating that O-2Aadult progenitors are capable of prolonged self renewal in vitro. In addition, our data suggests that the in vitro generation of oligodendrocytes from O-2Aadult progenitors occurs primarily through asymmetric division and differentiation, in contrast with the self-extinguishing pattern of symmetric division and differentiation displayed by O-2Aperinatal progenitors in vitro. We suggest that O-2Aadult progenitors express at least some properties of stem cells and thus may be able to support the generation of both differentiated progeny cells as well as their own continued replenishment throughout adult life.

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