Effects of oestradiol-17β and 5α-dihydrotestosterone on guinea-pig prostate smooth muscle cell proliferation and steroid receptor expression in vitro

1994 ◽  
Vol 140 (3) ◽  
pp. 373-383 ◽  
Author(s):  
C Ricciardelli ◽  
D J Horsfall ◽  
P J Sykes ◽  
V R Marshall ◽  
W D Tilley
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Dna Synthesis ◽  
Steroid Receptor ◽  
Inhibitory Effect ◽  
Cell Number ◽  
Mrna Levels ◽  
Plating Density ◽  
Stimulation Of

Abstract Smooth muscle cells (SMCs) are the major cellular component of the prostatic stroma. The aim of this study was to examine the effects of oestradiol-17β (OE2) and 5α-dihydrotestosterone (DHT) on the proliferation of guinea-pig prostate SMCs in vitro. OE2 stimulated SMC DNA synthesis at all concentrations examined. At a plating density of 3·0 × 104 cells/cm2, maximal incorporation of [3H]thymidine (136% of control) was observed after 36 h of treatment with 1 nmol OE2/l. At the same plating density, DHT had an inhibitory effect on SMC DNA synthesis, with maximal effects (73% of control) being observed 24 h after treatment with 1 nmol DHT/l. These effects of OE2 and DHT were prevented by co-incubation with specific steroid receptor antagonists. At a threefold lower plating density (1·0 × 104 cells/cm2), the maximal stimulatory and inhibitory effects of OE2 and DHT were delayed by approximately 24 and 12 h respectively. At the lower plating density, a biphasic effect of DHT was observed on DNA synthesis; DHT was both inhibitory and stimulatory. Maximal inhibition (71% of control) and maximal stimulation (168% of control) were observed after 36 and 134 h treatment with DHT respectively. At the lower plating density, longer term treatment of SMC cultures with OE2 and DHT also resulted in an increase in cell number. After 7 days of treatment with OE2 and DHT, cell number increased by 13% and 12% respectively. When OE, and DHT were added in combination, the short-term inhibitory effect of DHT on SMC DNA synthesis was dominant over the stimulatory effect of OE2. Treatment with DHT for 24 h significantly inhibited OE2-induced stimulation of [3H] thymidine incorporation, irrespective of the prior duration of OE2 treatment. At the lower plating density, OE2 also decreased oestrogen receptor (ER) mRNA levels to 38% of control levels after 24 h of treatment. ER mRNA levels remained repressed until 72 h after treatment with OE2, and returned to control values following 96 h of treatment. Both the androgen-induced inhibition and stimulation of DNA synthesis observed following treatment of SMCs with 1 nmol DHT/l were associated with a reduction in androgen receptor (AR) mRNA levels. At an intermediate time (i.e. 48 h after commencement of treatment with DHT) AR mRNA levels were increased more than twofold over control levels. The increase in AR mRNA levels at 48 h after DHT treatment only occurred in cells plated at the lower density, suggesting that this is an essential requirement for the longer term stimulation of prostatic SMC proliferation by DHT. Journal of Endocrinology (1994) 140, 373–383

Effects of ACTH and ACTH fragments on DNA synthesis in guinea-pig adrenal segments kept in organ culture

1987 ◽  
Vol 115 (3) ◽  
pp. 505-510 ◽  
Author(s):  
N. M. Wulffraat ◽  
H. A. Drexhage ◽  
P. Jeucken ◽  
R. D. van der Gaag ◽  
W. M. Wiersinga
Keyword(s):  
Guinea Pig ◽  
Organ Culture ◽  
Dna Synthesis ◽  
Intermediate Lobe ◽  
Terminal Part ◽  
Terminal Fragment ◽  
Acth Fragments ◽  
Epidermal Growth ◽  
Stimulation Of

ABSTRACT Stimulation of adrenal DNA synthesis by ACTH(1–39) and its fragments ACTH(1–24) (Synacthen) and ACTH(18–39) was investigated. Synthesis of DNA was measured as the increase in the percentage of cells in S-phase (Feulgen densitometry) in guinea-pig adrenal explants kept in organ culture and exposed to the peptides for 5 h at 37 °C. ACTH(1–39) and its C-terminal fragment ACTH(18–39) (corticotrophin-like intermediate lobe peptide) were found to be potent stimulators of in-vitro adrenal DNA synthesis. The dose–response kinetics were biphasic and optimal responsiveness was reached in both instances at 1 fmol/1–10 pmol/l (this biological effect of ACTH(18–39) has hitherto not been described). The N-terminal fragment ACTH(1–24) gave only minimal responses. Thyrotrophin and LH, tested as controls, did not induce adrenal DNA synthesis. Epidermal growth factor was a potent stimulator of adrenal DNA synthesis in vitro. Our data suggest a trophic action of the C-terminal part (ACTH(18–39)) of the corticotrophic molecule. Clear trophic effects were also found for the N-terminal part of the pro-opiomelanocortin molecule N-POC(1–76) (optimum 0·1 nmol/l) and N-POC(51– 62) (optimum 0·1 pmol/l). The latter observations support earlier concepts that this part of the proopiomelanocortin molecule has a stimulatory effect on adrenal DNA synthesis. J. Endocr. (1987) 115, 505–510

Selectlve desensitization of 5-hydroxytryptamine 2A receptor mediated contraction in guinea pig trachea

1994 ◽  
Vol 72 (5) ◽  
pp. 463-470 ◽  
Author(s):  
Stephanie W. Watts ◽  
Kathryn W. Schenck ◽  
Marlene L. Cohen
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Jugular Vein ◽  
Rat Aorta ◽  
Receptor Desensitization ◽  
Maximal Contraction ◽  
High Concentrations ◽  
Over Time ◽  
Stimulation Of

5-Hydroxytryptamine (serotonin, 5-HT) contracts the guinea pig trachea through stimulation of 5-HT2A receptors, an effect previously reported to rapidly desensitize. The present studies were designed to examine further the putative desensitization to serotonin. In vitro studies investigating functional desensitization of the guinea pig tracheal 5-HT2A receptor documented that 5-HT (3 × 10−7 M) significantly (50%) but incompletely reduced subsequent tracheal maximal contraction to 5-HT. In contrast, an equieffective concentration of carbamylcholine (3 × 10−8 M) did not reduce guinea pig tracheal contraction to 5-HT. Furthermore, 5-HT (3 × 10−7 M) did not diminish tracheal contraction to carbamylcholine. These data indicate that 5-HT can selectively desensitize guinea pig tracheal contraction to 5-HT. In addition, 5-HT-induced contraction but not carbamylcholine-induced contraction in guinea pig trachea declined over time, an effect that was more pronounced at high concentrations of 5-HT (1 × 10−6 and 1 × 10−5 M). Inhibitors of mechanisms that oppose contractility to 5-HT (5-HT-induced relaxation, uptake of 5-HT, or metabolism of 5-HT) did not reverse the decline in contraction to 5-HT (1 × 10−5 M). The decline in 5-HT-induced contraction was most rapid in the guinea pig trachea and less so in the rat jugular vein and rat aorta, two preparations in which 5-HT induced contraction also occurred via activation of 5-HT2A receptors. These studies suggest that 5-HT can functionally and selectively desensitize the 5-HT2A receptor in guinea pig trachea, an effect not likely to be related to opposing actions of 5-HT or reduction in concentration of 5-HT.Key words: phosphatidylinositol hydrolysis, receptor desensitization, smooth muscle.

Catecholamines Abrogate the Anti-Mitogenic Effects of 2-Hydroxy Metabolite of Estradiol on Vascular Smooth Muscle Cells by Inhibiting Catechol-O-Methyltransferase (COMT) Activity and 2-Methoxyestradiol Formation

Hypertension ◽  
2000 ◽  
Vol 36 (suppl_1) ◽  
pp. 705-706
Author(s):  
Lefteris C Zacharia ◽  
Edwin K Jackson ◽  
Delbert G Gillespie ◽  
Raghvendra K Dubey
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Dna Synthesis ◽  
Angiogenesis Inhibitor ◽  
Inhibitory Effect ◽  
Cell Number ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Local Synthesis ◽  
The Right

P70 Methylation of 2-hydroxyestradiol(2OHE; endogenous estradiol metabolite) to 2-methoxyestradiol (2MeOE; angiogenesis inhibitor)by COMT plays a key role in mediating the anti-mitogenic effects of 2OHE on vascular smooth muscle cell (SMC)growth. Catecholamines such as norepinephrine (NE) are also substrates for COMT and increased levels of NE are associated with vasoocclusive disorders. We hypothesize that increased endogenous synthesis/levels of NE under pathophysiological conditions may abrogate the vasoprotective effects of 2OHE by competing for COMT and inhibiting 2MeOE formation. To test this hypothesis we investigated the anti-mitogenic effects of .001-10μM 2OHE on 2.5% FCS-induced SMC growth (cell number, DNA synthesis [thymidine incorporation], collagen synthesis [proline incorporatio])in rat and human aortic SMCs in the presence and absence of NE (0.1-40μM). NE concentration-dependently abrogated the inhibitory effects of 2OHE on SMC growth and in the presence of 10μM NE the inhibitory curve of 2OHE on SMC growth was shifted to the right(P<.05). In the presence of 10μM NE, the inhibitory effect of 1μM 2OHE on DNA synthesis was reduced from 70±3% to 24±2% (P<.05), and this effect of NE was mimicked by isoproterenol (ISO) and epinephrine (EPI). Additionally, NE (0.5-2.5mM) inhibited the metabolism of 10μM 2OHE to 2MeOE in a concentration-dependent manner and the effects of NE were mimicked by ISO, EPI, metanephrine, normetanephrine and 3,4-dihydroxymandelic acid. At 0.5 mM ISO, NE and EPI inhibited 2MeoE formation by 70±4%,20±2% and 40±2%, respectively. Our findings suggest that increases in local synthesis of catecholamines within the vasculature may abrogate the anti-vasoocclusive effects of estradiol and 2OHE by blocking 2MeOE formation. In conclusion, the interaction between catecholamines and 2OHE may play a key role in the biology of vascular SMC growth.

Inhibition of Human and Animal Platelet Adhesiveness to Glass Bead Columns by Adenosine, Dipyridamole, Chlorpromazine and Acetylsalicylic Acid

1976 ◽  
Vol 36 (02) ◽  
pp. 401-410 ◽  
Author(s):  
Buichi Fujttani ◽  
Toshimichi Tsuboi ◽  
Kazuko Takeno ◽  
Kouichi Yoshida ◽  
Masanao Shimizu
Keyword(s):  
Guinea Pig ◽  
Acetylsalicylic Acid ◽  
Guinea Pigs ◽  
Glass Bead ◽  
Animal Species ◽  
Inhibitory Effect ◽  
Rabbit Platelet ◽  
Platelet Adhesiveness

SummaryThe differences among human, rabbit and guinea-pig platelet adhesiveness as for inhibitions by adenosine, dipyridamole, chlorpromazine and acetylsalicylic acid are described, and the influence of measurement conditions on platelet adhesiveness is also reported. Platelet adhesiveness of human and animal species decreased with an increase of heparin concentrations and an increase of flow rate of blood passing through a glass bead column. Human and rabbit platelet adhesiveness was inhibited in vitro by adenosine, dipyridamole and chlorpromazine, but not by acetylsalicylic acid. On the other hand, guinea-pig platelet adhesiveness was inhibited by the four drugs including acetylsalicylic acid. In in vivo study, adenosine, dipyridamole and chlorpromazine inhibited platelet adhesiveness in rabbits and guinea-pigs. Acetylsalicylic acid showed the inhibitory effect in guinea-pigs, but not in rabbits.

Thrombopoietin-Induced Stimulation of Megakaryocyte- Enriched Bone Marrow Cultures

1979 ◽  
Author(s):  
K. L. Kellar ◽  
B. L. Evatt ◽  
C. R. McGrath ◽  
R. B. Ramsey
Keyword(s):  
Bone Marrow ◽  
Dna Synthesis ◽  
Bone Marrow Cells ◽  
Rabbit Plasma ◽  
Bone Marrow Cultures ◽  
Plasma Fractions ◽  
Marrow Cultures ◽  
Stimulation Of

Liquid cultures of bone marrow cells enriched for megakaryocytes were assayed for incorporation of 3H-thymidine (3H-TdR) into acid-precipitable cell digests to determine the effect of thrombopoietin on DNA synthesis. As previously described, thrombopoietin was prepared by ammonium sulfate fractionation of pooled plasma obtained from thrombocytopenic rabbits. A control fraction was prepared from normal rabbit plasma. The thrombopoietic activity of these fractions was determined in vivo with normal rabbits as assay animals and the rate of incorporation of 75Se-selenomethionine into newly formed platelets as an index of thrombopoietic activity of the infused material. Guinea pig megakaryocytes were purified using bovine serum albumin gradients. Bone marrow cultures containing 1.5-3.0x104 cells and 31%-71% megakaryocytes were incubated 18 h in modified Dulbecco’s MEM containing 10% of the concentrated plasma fractions from either thrombocytopenic or normal rabbits. In other control cultures, 0.9% NaCl was substituted for the plasma fractions. 3H-TdR incorporation was measured after cells were incubated for 3 h with 1 μCi/ml. The protein fraction containing thrombopoietin-stimulating activity caused a 25%-31% increase in 3H-TdR incorporation over that in cultures which were incubated with the similar fraction from normal plasma and a 29% increase over the activity in control cultures to which 0.9% NaCl had been added. These data suggest that thrombopoietin stimulates DNA synthesis in megakaryocytes and that this tecnique may be useful in assaying thrombopoietin in vitro.

scholarly journals Contractile and Endothelium-Dependent Dilatory Responses of Cerebral Arteries at Various Extracellular Magnesium Concentrations

1991 ◽  
Vol 11 (1) ◽  
pp. 161-164 ◽  
Author(s):  
Mária Faragó ◽  
Csaba Szabó ◽  
Eörs Dóra ◽  
Ildikó Horváth ◽  
Arisztid G. B. Kovách
Keyword(s):  
Smooth Muscle ◽  
Vascular Reactivity ◽  
Calcium Influx ◽  
Cerebral Arteries ◽  
Inhibitory Effect ◽  
Contractile Responses ◽  
Middle Cerebral Arteries ◽  
The Right ◽  
Endothelial Receptor

To clarify the effect of extracellular magnesium (Mg2+) on the vascular reactivity of feline isolated middle cerebral arteries, the effects of slight alterations in the Mg2+ concentration on the contractile and endothelium-dependent dilatory responses were investigated in vitro. The contractions, induced by 10−8-10−5 M norepinephrine, were significantly potentiated at low Mg2+ (0.8 m M v. the normal, 1.2 m M). High (1.6 and 2.0 m M) Mg2+ exhibited an inhibitory effect on the contractile responses. No significant changes, however, in the EC50 values for norepinephrine were found. The endothelium-dependent relaxations induced by 108–10−5 M acetylcholine were inhibited by high (1.6 and 2.0 m M) Mg2+. Lowering of the Mg2+ concentration to 0.8 m M or total withdrawal of this ion from the medium failed to alter the dilatory potency of acetylcholine. The changes in the dilatory responses also shifted the EC50 values for acetylcholine to the right. The present results show that the contractile responses of the cerebral arteries are extremely susceptible to the changes of Mg2+ concentrations. In response to contractile and endothelium-dependent dilatory agonists, Mg2+ probably affects both the calcium influx into the endothelial and smooth muscle cells as well as the binding of acetylcholine to its endothelial receptor. Since Mg2+ deficiency might facilitate the contractile but not the endothelium-dependent relaxant responses, the present study supports a role for Mg2+ deficiency in the development of the cerebral vasospasm.

scholarly journals Regulation of interleukin 6 receptor expression in human monocytes and monocyte-derived macrophages. Comparison with the expression in human hepatocytes.

1989 ◽  
Vol 170 (5) ◽  
pp. 1537-1549 ◽  
Author(s):  
J Bauer ◽  
T M Bauer ◽  
T Kalb ◽  
T Taga ◽  
G Lengyel ◽  
...  
Keyword(s):  
Plasma Cells ◽  
Human Peripheral Blood ◽  
Receptor Expression ◽  
Mrna Levels ◽  
Blood Monocytes ◽  
Inflammatory Conditions ◽  
High Concentrations ◽  
Human Primary Hepatocytes ◽  
Stimulation Of

IL-6 is a cytokine with pleiotropic biological functions, including induction of the hepatic acute phase response and differentiation of activated B cells into Ig-secreting plasma cells. We found that human peripheral blood monocytes express the IL-6-R, which is undetectable on the large majority of lymphocytes of healthy individuals. Stimulation of monocytes by endotoxin or IL-1 causes a rapid downregulation of IL-6-R mRNA levels and a concomitant enhancement of IL-6 mRNA expression. IL-6 itself was found to suppress the IL-6-R at high concentrations. A gradual decrease of IL-6-R mRNA levels was observed along in vitro maturation of monocytes into macrophages. We show that downregulation of IL-6-R mRNA levels by IL-1 and IL-6 is monocyte specific, since IL-6-R expression is stimulated by both IL-1 and IL-6 in cultured human primary hepatocytes. Our data indicate that under noninflammatory conditions, monocytes may play a role in binding of trace amounts of circulating IL-6. Repression of monocytic IL-6-R and stimulation of hepatocytic IL-6-R synthesis may represent a shift of the IL-6 tissue targets under inflammatory conditions.

scholarly journals A Newly Authenticated Compound from Traditional Chinese Medicine Decoction Induces Melanogenesis in B16-F10 Cells by Increasing Tyrosinase Activity

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Xiu Juan Xin ◽  
Jiahong Zou ◽  
Tao Zou ◽  
Huoli Shang ◽  
Li Yun Sun
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Cell Number ◽  
Tyrosinase Activity ◽  
Chinese Traditional Medicine ◽  
Inhibition Rate ◽  
Disease Treatment ◽  
Protein Levels ◽  
Stimulation Of

Vitiligo is a kind of skin dysfunction on melanogenesis. The highly prevalent, chronic, and distinctive complexion changes on patients have imposed enormous psychic and economic burden on both individuals and society. Traditional Chinese Medicine (TCM) is a kind of precious source on chronic disease treatment, including skin dysfunctional diseases. In our previous study, a new compound named apigenin-7-butylene glucoside has been authenticated and purified from a prescription of Chinese traditional medicine formula which has been used clinically in vitiligo treatment. The aim of this work is to evaluate the effects of this compound on melanogenesis using melanoma cell B16-F10 in vitro. The results showed that apigenin-7-butylene glucoside had almost no cytotoxicity on B16-F10 cells within a lower dose of 5.0 μg ml-1 and enhanced the melanin level to about 41% and tyrosinase activity to 1.32-fold when compared with controls. The compound showed minor cytotoxicity to B16-F10 cells at the higher concentration of 10 μg ml-1 and 50 μg ml-1, the inhibition rate was 8.4% and 11.8%, and the melanin level and tyrosinase activity showed a decreased trend because of the lower cell number at the higher concentrations. The results indicated that apigenin-7-butylene glucoside was safe to B16-F10 cells within a lower concentration, <5.0 μg ml-1. Incubated with 5.0 ug ml-1of apigenin-7-butylene glucoside for 48 hours, the mRNA and protein levels of Tyr, Trp-1, and Trp-2 genes were all increased except Mitf in B16-F10 cells. The stimulation of apigenin-7-butylene glucoside on melanogenesis of B16-F10 cells through Tyr, Trp-1, and Trp-2 pathway highlighted the potential usage of the compound in vitiligo treatment.

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