Oestrogen secretion by in-vitro perfused testes: species comparison and factors affecting short-term secretion

1983 ◽  
Vol 96 (1) ◽  
pp. 97-105 ◽  
Author(s):  
D. L. Thompson ◽  
L. L. Ewing ◽  
B. L. Lasley
Keyword(s):  
High Performance ◽  
Time Course ◽  
Dependent Manner ◽  
Short Term ◽  
Factors Affecting ◽  
Arterial Perfusion ◽  
Testosterone Secretion ◽  
Time Course Study ◽  
Dose Dependent

Testes from mature rats, rabbits, hamsters, guinea-pigs and dogs were perfused in vitro with added gonadotrophins to study the qualitative and quantitative aspects of oestrogen secretion by these species. After separation by high performance liquid chromatography (HPLC), the major oestrogen secreted by the testes of all five species was oestradiol-17β; lesser amounts of oestrone were also detected for all species. Secretion rates of oestradiol and testosterone were determined for one testis from each of six animals of each species after purification by HPLC. Oestradiol and testosterone secretion varied (P < 0·05) among species on both per testis and per gram of testis bases. The rabbit, which was a high secretor of oestradiol, was used in subsequent experiments to study the factors which affect short-term oestradiol secretion by perfused testes. Luteinizing hormone (NIAMDD-LH-S21) at 100 ng/ml significantly stimulated oestradiol secretion by 2·9-fold and increased testosterone secretion by 155-fold. Follicle-stimulating hormone (NIH-FSH-S11) had no significant effect on secretion of either steroid. In a time-course study in which LH stimulation was started after 45 min of control perfusion, the rates of increase in oestradiol and testosterone secretion over time were similar. Increasing amounts of testosterone added directly to the arterial perfusion medium (0–10 μg/ml) resulted in an increase in oestradiol secretion in the absence of gonadotrophins. Oestradiol secretion increased in a dose-dependent manner up to 1·0 μg testosterone/ml; there was no further stimulation of oestradiol secretion at 10 μg testosterone/ml. When testes were perfused with saturating concentrations of testosterone (10 μg/ml) neither LH nor FSH at 100 ng/ml increased oestradiol secretion above control values. It appears that the major factor affecting oestradiol secretion by in-vitro perfused rabbit testes is the amount of substrate (testosterone) available for aromatization.

Effects of pinacidil on coronary Ca2+-myosin phosphorylation in cold potassium cardioplegia model

2000 ◽  
Vol 279 (3) ◽  
pp. H882-H888 ◽  
Author(s):  
Naruto Matsuda ◽  
Kathleen G. Morgan ◽  
Frank W. Sellke
Keyword(s):  
Time Course ◽  
Dependent Manner ◽  
Coronary Smooth Muscle ◽  
Intracellular Ca ◽  
No Signaling ◽  
Synthase Inhibitor ◽  
Mlc Phosphorylation ◽  
Dose Dependent ◽  
Cardioplegic Solutions

The effects of the potassium (K+) channel opener pinacidil (Pin) on the coronary smooth muscle Ca2+-myosin light chain (MLC) phosphorylation pathway under hypothermic K+cardioplegia were determined by use of an in vitro microvessel model. Rat coronary arterioles (100–260 μm in diameter) were subjected to 60 min of simulated hypothermic (20°C) K+cardioplegic solutions (K+= 25 mM). We first characterized the time course of changes in intracellular Ca2+concentration, MLC phosphorylation, and diameter and observed that the K+cardioplegia-related vasoconstriction was associated with an activation of the Ca2+-MLC phosphorylation pathway. Supplementation with Pin effectively suppressed the Ca2+accumulation and MLC phosphorylation in a dose-dependent manner and subsequently maintained a small decrease in vasomotor tone. The ATP-sensitive K+(KATP)-channel blocker glibenclamide, but not the nitric oxide (NO) synthase inhibitor Nω-nitro-l-arginine methyl ester, significantly inhibited the effect of Pin. K+cardioplegia augments the coronary Ca2+-MLC pathway and results in vasoconstriction. Pin effectively prevents the activation of this pathway and maintains adequate vasorelaxation during K+cardioplegia through a KATP-channel mechanism not coupled with the endothelium-derived NO signaling cascade.

scholarly journals Obestatin Modulates Ghrelin’s Effects on the Basal and Stimulated Testosterone Secretion by the Testis of Rat: an In Vitro Study

2017 ◽  
pp. 93-98
Author(s):  
T. AFSAR ◽  
S. JAHAN ◽  
S. RAZAK ◽  
A. ALMAJWAL ◽  
M. ABULMEATY ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Inhibitory Effect ◽  
Human Chorionic Gonadotrophin ◽  
Dependent Manner ◽  
Control Groups ◽  
Adult Rats ◽  
Testosterone Secretion ◽  
Functional Antagonism ◽  
Dose Dependent

The functional antagonism between obestatin and ghrelin in the testis is under investigation. We investigated the ability of obestatin to counteract the inhibitory effect of ghrelin on basal and stimulated testosterone (T) secretion in vitro. Testicular strips from adult rats were incubated with 10 ng/ml and 100 ng/ml of obestatin alone, ghrelin alone and obestatin + ghrelin. Obestatin modulation of stimulated T secretion was evaluated by incubation of testicular samples with 10 ng/ml and 100 ng/ml obestatin, ghrelin and obestatin + ghrelin in the absence and presence of 10 IU of human chorionic gonadotrophin (hCG). T concentrations in the hCG treated groups were significantly (P<0.0001) higher than those in the control groups. Obestatin caused a significant increase in basal T secretion in a dose-dependent manner; however, obestatin at the both 10 ng/ml and 100 ng/ml significantly (P<0.0001) increased hCG-stimulated T secretion. In contrast, ghrelin in a dose-dependent manner significantly (P<0.001) decreased both basal and hCG-induced T secretion by testicular slices. Obestatin opposed the inhibitory effect of ghrelin on T secretion under both basal and hCG-stimulated conditions at all doses tested. In conclusions, administration of obestatin was able to antagonize the inhibitory effect of ghrelin on testosterone secretion in vitro.

15-HETE-substituted diglycerides selectively regulate PKC isotypes in human tracheal epithelial cells

1999 ◽  
Vol 277 (3) ◽  
pp. L457-L464 ◽  
Author(s):  
Stephen E. Alpert ◽  
Ronald W. Walenga ◽  
Atashi Mandal ◽  
Nicole Bourbon ◽  
Mark Kester
Keyword(s):  
High Performance ◽  
Neutral Lipids ◽  
Platelet Activating Factor ◽  
Dependent Manner ◽  
Western Blots ◽  
Tracheal Epithelial Cells ◽  
Tracheal Epithelial ◽  
Layer Chromatography ◽  
Dose Dependent

Human tracheal epithelial (TE) cells selectively incorporate their major lipoxygenase product, 15-hydroxyeicosatetraenoic acid (15-HETE), into the sn-2 position of phosphatidylinositol (PI) (S. E. Alpert and R. W. Walenga. Am. J. Respir. Cell Mol. Biol. 8: 273–281, 1993). Here we investigated whether 15-HETE-PI is a substrate for receptor-mediated generation of 15-HETE-substituted diglycerides (DGs) and whether these 15-HETE-DGs directly activate and/or alter conventional diacylglycerol-induced activation of protein kinase C (PKC) isotypes in these cells. Primary human TE monolayers incubated with 0.5 μM 15-[3H]-HETE or 15-[14C]HETE for 1–2 h were stimulated with 1 nM to 1 μM platelet-activating factor (PAF) for 30 s to 6 min, and the radiolabel in the medium, cellular phospholipids, and neutral lipids was assessed by high-performance liquid and thin-layer chromatography. PAF mobilized radiolabel from PI in a dose-dependent manner (22 ± 5% decrease after 1 μM PAF) without a concomitant release of free intra- or extracellular 15-HETE. 14C-labeled DGs were present in unstimulated TE monolayers incubated with 15-[14C]HETE, and the major 14C band, identified as sn-1,2-15-[14C]HETE-DG, increased transiently in response to PAF. Western blots of freshly isolated and cultured human TE cells revealed PKC isotypes α, βI, βII, δ, ε, and ζ. In vitro, cell-generated sn-1,2-15-[14C]HETE-DG selectively activated immunoprecipitated PKC-α and inhibited diacylglycerol-induced activation of PKC-α, -δ, -βI, and -βII. Our observations indicate that 15-HETE-DGs can modulate the activity of PKC isotypes in human TE cells and suggest an intracellular autocrine role for 15-HETE in human airway epithelia.

scholarly journals Anti-Inflammatory Activity of Four Triterpenoids Isolated from Poriae Cutis

Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3155
Author(s):  
Lijia Zhang ◽  
Mengzhou Yin ◽  
Xi Feng ◽  
Salam A. Ibrahim ◽  
Ying Liu ◽  
...  
Keyword(s):  
High Speed ◽  
High Performance ◽  
Inflammatory Activity ◽  
Raw 264.7 Cells ◽  
Raw 264.7 ◽  
Dependent Manner ◽  
Tnf Α ◽  
Anti Inflammatory ◽  
Dose Dependent

In this study, triterpenoid compounds from Poriae Cutis were separated by high-speed countercurrent chromatography (HSCCC) and identified using ultra-high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) and nuclear magnetic resonance (NMR). The in vitro anti-inflammatory activities of the purified triterpenoids on RAW 264.7 cells were also investigated. Triterpenoids, poricoic acid B, poricoic acid A, dehydrotrametenolic acid, and dehydroeburicoic acid were obtained; their levels of purity were 90%, 92%, 93%, and 96%, respectively. The results indicated that poricoic acid B had higher anti-inflammatory activity than those of poricoic acid A by inhibiting the generation of NO in lipopolysaccharide (LPS)-induced RAW 264.7 cells. However, dehydrotrametenolic acid and dehydroeburicoic acid had no anti-inflammatory activity. In addition, the production of cytokines (TNF-α, IL-1β, and IL-6) in cells treated with poricoic acid B decreased in a dose-dependent manner in the concentration range from 10 to 40 μg/mL. The results provide evidence for the use of Poriae Cutis as a natural anti-inflammatory agent in medicines and functional foods.

Influence of Newly Developed Resin and MMA Resin on Mouse Fibroblasts Cellular Viability

2006 ◽  
Vol 309-311 ◽  
pp. 817-820
Author(s):  
S. Jinno ◽  
T. Suzuki ◽  
A. Ishikawa ◽  
T. Hayashi ◽  
M. Deguchi ◽  
...  
Keyword(s):  
Phase Contrast ◽  
High Performance ◽  
Annexin V ◽  
Dependent Manner ◽  
Cellular Viability ◽  
Mouse Fibroblasts ◽  
Propidium Iodide Staining ◽  
Ic50 Value ◽  
Dose Dependent

The aim of this study is evaluate to the cellular viability of elution from the newly developed resin and Osteobond® in vitro. The basis of the newly developed resin are methacryloyloxyethyl methyl succinate and 1,6-Hexanediol dimethacrylate. The basis of Osteobond is methyl methacrylate. The concentrations of basis in each elution were determined by high-performance liquid chromatography (HPLC). Cellular viabilities of L-929 mouse fibroblasts were evaluated by direct cells counting, and then, each IC50 value was calculated. Moreover, patterns of cell death were analyzed using annexin V/propidium iodide staining with the phase-contrast microscope and flow cytometry. The concentration of Osteobond elution was 2.16 mM of MMA, and the newly developed resin elution was 1.02 mM of TA and 1.87 x 10-2 mM of HX. Until 72 hours of incubation, treatment with each elution impaired the viability of L-929 cells in a dose-dependent manner. IC50 value of Osteobond was 6.48 x 10-4 mM of MMA. However, IC50 of the newly developed resin was not calculated. Treatment with Osteobond elution showed more necrotic cells than with the newly developed resin elution. In conclusion, the results demonstrated much more excellent cellular viability of the newly developed resin than that of MMA resin. Thus, it is suggested that the newly developed resin will be more useful as an implantation material for dentistry and orthopaedics.

Metabolism of 25-hydroxyvitamin D3 to 24,25-dihydroxyvitamin D3 and its sensitivity to ketoconazole in 1α,25-dihydroxyvitamin D3-differentiated HL60 cells

1989 ◽  
Vol 3 (3) ◽  
pp. 199-205 ◽  
Author(s):  
M. E. Hayes ◽  
D. Bayley ◽  
E. B. Mawer
Keyword(s):  
High Performance ◽  
Cell Number ◽  
Dependent Manner ◽  
Macrophage Phenotype ◽  
Dihydroxyvitamin D3 ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Dose Dependent

ABSTRACT Regulation of the metabolism of [3H]25-hydroxyvitamin D3 ([3H]25-(OH)D3) in vitro to material with the characteristics of [3H]24,25-dihydroxyvitamin D3 ([3H]24,25-(OH)2D3) has been studied in the human promyelocytic cell line HL60. Synthesis of 24,25-(OH)2D3 was induced in a dose-dependent manner in cells pretreated with 0·1–100 nm 1α,25-dihydroxyvitamin D3 (1α,25-(OH)2D3) for 4 days. This treatment also inhibited cell proliferation and stimulated differentiation to a macrophage phenotype that was characterized by staining for non-specific esterase (NSE) activity. The ability to synthesize [3H]24,25-(OH)2D3 from [3H]25-(OH)D3 and the expression of NSE activity both responded to changes in concentration of 1α,25-(OH)2D3 in the culture medium in a parallel manner. Synthesis of [3H]24,25-(OH)2D3 was linear when the incubation time was between 1 and 8 h and the cell number between 1 and 12×106 cells/incubation. The optimum substrate concentration for its synthesis was 125 nm, giving an apparent Michaelis constant of 360 nm. The identity of the [3H]24,25-(OH)2D3 synthesized by these cells was confirmed by co-chromatography with authentic 24,25-(OH)2D3 on normal-phase and reverse-phase high-performance liquid chromatography systems and by its reaction to sodium-m-periodate. Cells that had been exposed to 100 nm 1α,25-(OH)2D3 for 4 days synthesized 2·17±0·07 (s.e.m.) pmol 24,25-(OH)2D3/106 cells per h. This synthesis was inhibited in a dose-dependent manner over a concentration range of 0·01–1 μm by the drug ketoconazole, an antimycotic imidazole which is a known inhibitor of certain cytochrome P-450 enzyme systems, suggesting that the HL60 25-(OH)D3-24-hydroxylase is also a P-450-dependent enzyme system.

In vitro stimulation of Na-K-ATPase in rat thick ascending limb by dexamethasone

1986 ◽  
Vol 251 (5) ◽  
pp. F851-F857 ◽  
Author(s):  
A. Doucet ◽  
A. Hus-Citharel ◽  
F. Morel
Keyword(s):  
Atpase Activity ◽  
Sodium Reabsorption ◽  
Thick Ascending Limb ◽  
Dependent Manner ◽  
Short Term ◽  
Medullary Thick Ascending Limb ◽  
Dose Dependent ◽  
Stimulation Of

Dexamethasone has been reported to stimulate Na-K-ATPase activity in the medullary thick ascending limb of adrenalectomized animals within a few hours. The present study was aimed at characterizing the mechanism of this action by investigating the stimulatory effect of the hormone in vitro. Dexamethasone (10(-8) M) added in vitro to segments of the medullary thick ascending limb of Henle's loop, which were microdissected from adrenalectomized rats, restored in a dose-dependent manner the depressed Na-K-ATPase activity within one h of incubation. This stimulation of Na-K-ATPase was inhibited by cycloheximide and actinomycin D. Dexamethasone also stimulated the component of oxidative metabolism coupled to sodium transport. These results, which confirm previous in vivo observations, demonstrate that dexamethasone-induced stimulation of Na-K-ATPase is a direct tubular action of the hormone mediated by protein synthesis. They suggest that this short-term effect of dexamethasone corresponds to the stimulation of sodium reabsorption by the dilution segment.

Oxygenation of 18-hydroxycorticosterone as the final reaction for aldosterone biosynthesis

1984 ◽  
Vol 107 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Itaru Kojima ◽  
Etsuro Ogata ◽  
Hiroshi Inano ◽  
Bun-ichi Tamaoki
Keyword(s):  
Carbon Monoxide ◽  
Hydroxysteroid Dehydrogenase ◽  
Dependent Manner ◽  
In Vitro Production ◽  
Mitochondrial Preparation ◽  
Final Reaction ◽  
Vitro Production ◽  
Dose Dependent ◽  
Cytochrome P 450

Abstract. Incubation of 18-hydroxycorticosterone with the sonicated mitochondrial preparation of bovine adrenal glomerulosa tissue leads to the production of aldosterone, as measured by radioimmunoassay. The in vitro production of aldosterone from 18-hydroxycorticosterone requires both molecular oxygen and NADPH, and is inhibited by carbon monoxide. Cytochrome P-450 inhibitors such as metyrapone, SU 8000. SU 10603, SKF 525A, amphenone B and spironolactone decrease the biosynthesis of aldosterone from 18-hydroxycorticosterone. These results support the conclusion that the final reaction in aldosterone synthesis from 18-hydroxycorticosterone is catalyzed by an oxygenase, but not by 18-hydroxysteroid dehydrogenase. By the same preparation, the production of [3H]aldosterone but not [3H]18-hydroxycorticosterone from [1,2-3H ]corticosterone is decreased in a dose-dependent manner by addition of non-radioactive 18-hydroxycorticosterone.

Appraisal of Immunological Impacts of Melaleuca leucadendra Extract over Macrophage Performance in Vitro

2020 ◽  
Keyword(s):  
Nitric Oxide ◽  
Interleukin 2 ◽  
Dependent Manner ◽  
Reduced Pressure ◽  
Medical Plant ◽  
Dose Dependent ◽  
Level Production ◽  
Melaleuca Leucadendra ◽  
Phagocytic Killing

This trial research was performed to discuss the immune-influence of Melaleuca leucadendra ‘paper-bark tree’ dried leaves which is an important medical plant known in many regions in the world. The leaves were dissolved in a mixture of (ethanol + water) (3:1) mixture, then filtered, evaporated and dried under reduced pressure to obtain leaves extract. The macrophages of blood derived origin were provided from rats and mixed with three different leaves extracts doses in tissue culture plates and incubated then stained with fluorescent acridine orange and examined under fluorescent microscope to assess the phagocytic and killing potency. The wells contents were aspirated and assayed for nitric oxide and interleukin-2 levels. The results displayed an obvious increase in phagocytic, killing performance as well as nitric oxide and IL-2 level production than control in a dose dependent manner. The obtained results suggested the immune-stimulant impact of the paper-bark tree leaves.

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