Estrogenic Modulation of Ionic Channels, Pumps and Exchangers in Airway Smooth Muscle.

To preserve ionic homeostasis (primarily Ca2+, K+, Na+, and Cl-), in the airway smooth muscle (ASM) numerous transporters (channels, exchangers, and pumps) regulate the influx and efflux of these ions. Many of intracellular processes depend on continuous ionic permeation, including exocytosis, contraction, metabolism, transcription, fecundation, proliferation, and apoptosis. These mechanisms are precisely regulated, for instance, through hormonal activity. The lipophilic nature of steroidal hormones allows their free transit into the cell where, in most cases, they occupy their cognate receptor to generate genomic actions. In the sense, estrogens can stimulate development, proliferation, migration, and survival of target cells, including in lung physiology. Non-genomic actions on the other hand do not imply estrogen's intracellular receptor occupation, nor do they initiate transcription and are mostly immediate to the stimulus. Among estrogen's non genomic responses regulation of calcium homeostasis and contraction and relaxation processes play paramount roles in ASM. On the other hand, disruption of calcium homeostasis has been closely associated with some ASM pathological mechanism. Thus, this paper intends to summarize the effects of estrogen on ionic handling proteins in ASM. The considerable diversity, range and power of estrogens regulates ionic homeostasis through genomic and non-genomic mechanisms.

Antinociceptive effect of LMH-2, a new sigma-1 receptor antagonist analog of haloperidol, on the neuropathic pain of diabetic mice.

This study evaluates the antiallodynic and antihyperalgesic effects of LMH-2, a new haloperidol (HAL) analog that acts as sigma-1 receptor (σ1 R) antagonist, in diabetic mice using a model of neuropathic pain induced by chronic hyperglycemia. Additionally, we compared its effects with those of HAL. Hyperglycemia was induced in mice by nicotinamide-streptozotocin administration (NA-STZ, 50-130 mg/kg). Four weeks later, mechanical allodynia was assessed using the up-down method, and hyperalgesia was evoked with formalin 0.5%. We evaluated antiallodynic and antihyperalgesic effects of LMH-2 (5.6-56.2 mg/kg), HAL (0.018-0.18 mg/kg) and gabapentin (GBP, 5.6-56.2 mg/kg). The results showed that LMH-2 had a more significant antiallodynic effect compared to HAL and GBP (90.4±8.7 vs 75.1±3.1 and 41.9±2.3%, respectively; P<0.05), as well as an antihyperalgesic effect (96.3±1.2 vs 86.9±7.41 and 86.9±4.8%, respectively; P<0.05). Moreover, the antiallodynic and antihyperalgesic effect of both LMH-2 and HAL were completely abolished by PRE-084 (σ1 R agonist); and partially by pramipexole (a D2-like receptor agonist). Finally, the effect of all treatments on the rotarod test, barra, open field and exploratory behaviors showed that LMH-2 did not alter the animals' balance or the exploratory behavior, unlike as HAL or GBP. The molecular docking included indicate that LMH-2 has lower affinity to the D2R than HAL. These results provide evidence that LMH-2 exerts its antinociceptive effects as a σ1 R antagonist without the adverse effects induced by HAL or GBP. Consequently, LMH-2 can be considered a good and safe strategy for treating neuropathic pain caused by hyperglycemia in patients with diabetes.

Hemostatic Effects of Raloxifene in Ovariectomized Rats.

This study aimed to explore the effects of raloxifene (Rx) and estradiol (E2) on prothrombin time (PT), partial thromboplastin time (APTT), coagulation factors (VII, X, XI), and fibrinogen concentrations in rats. Female rats were ovariectomized 11 days prior to starting the treatment. Afterward, they received Rx or E2 (1, 10, 100, and 1000 µg/kg) or propylene glycol (0.3 mL; vehicle, V) subcutaneously for 3 consecutive days. Plasma was collected to measure the hemostatic parameters. Rx significantly increased PT (8%, at 1000 µg/kg; p < 0.05) and APTT at all doses evaluated (32, 70, 67, 30%; p < 0.05, respectively). Rx (1, 10, 100, and 1000 µg/kg) decreased the activity of factor VII by -20, -40, -37, and -17% (p < 0.05), respectively, and E2 increased it by 9, 34, 52, and 29%. Rx reduced factor X activity at 10 and 100 µg/kg doses (-30, and -30% p < 0.05), and E2 showed an increment of 24% with 1000 µg/kg dose only. Additionally, Rx (1, 10, 100 µg/kg) diminished FXI activity (-71, -62, -66; p < 0.05), E2 (1 and 10 µg/kg) in -60 and -38, respectively (p < 0.05), and Rx (1000 µg/kg) produced an increment of 29% (p < 0.05) in fibrinogen concentration, but not E2. Our findings suggest that raloxifene has a protective effect on hemostasis in rats.

Hypoxia Induces Alterations in the Circadian Rhythm in Patients with Chronic Respiratory Diseases.

The function of the circadian cycle is to determine the natural 24 h biological rhythm, which includes physiological, metabolic, and hormonal changes that occur daily in the body. This cycle is controlled by an internal biological clock that is present in the body's tissues and helps regulate various processes such as sleeping, eating, and others. Interestingly, animal models have provided enough evidence to assume that the alteration in the circadian system leads to the appearance of numerous diseases. Alterations in breathing patterns in lung diseases can modify oxygenation and the circadian cycles; however, the response mechanisms to hypoxia and their relationship with the clock genes are not fully understood. Hypoxia is a condition in which the lack of adequate oxygenation promotes adaptation mechanisms and is related to several genes that regulate the circadian cycles, the latter because hypoxia alters the production of melatonin and brain physiology. Additionally, the lack of oxygen alters the expression of clock genes, leading to an alteration in the regularity and precision of the circadian cycle. In this sense, hypoxia is a hallmark of a wide variety of lung diseases. In the present work, we intended to review the functional repercussions of hypoxia in the presence of asthma, chronic obstructive sleep apnea, lung cancer, idiopathic pulmonary fibrosis, obstructive sleep apnea, influenza, and COVID-19 and its repercussions on the circadian cycles.

Ceftriaxone and clavulanic acid induce antiallodynia and anti-inflammatory effects in rats using the carrageenan model.

INTRODUCTION: Ceftriaxone (CFX) and clavulanic acid (CA) are 2 ß-lactam molecules widely used as antibiotics. However, several reports of their antiallodynic properties have been published in recent years. Although this effect has been considered mostly due to a GLT1 overexpression, these molecules have also been proven to induce direct immunomodulation. In this work, we determine the acute analgesic effect of CFX and CA in an inflammatory pain model and assess if their administration may induce anti-inflammatory effects. METHODS: The carrageenan (Carr) test was used as an inflammatory pain model. Both mechanical and thermal responses were analyzed after CFX and CA administration at different times. A plethysmometer was used to determine inflammation. Also, TNF-α and IL-10 serum concentrations were determined by enzyme-linked immunosorbent assay. RESULTS: Both CFX and CA induced a significant thermal antiallodynic effect 3 and 24 h after administration. Furthermore, CA induced a mechanical antiallodynic effect 30, 60, and 90 min after administration. Moreover, a significant anti-inflammatory effect was found for both molecules 24 h after Carr injection. Also, both CA and CFX modulated TNF-α and IL-10 serum concentrations at different times. CONCLUSION: Our results provide evidence that both CFX and CA cause an analgesic effect on a Carr inflammatory pain model and that said analgesic effect differs between each ß-lactam molecule. Furthermore, this effect may be related to an anti-inflammatory effect of both molecules and a direct TNF-α and IL-10 serum concentration modulation.

Gender and inter-species influence on coagulation tests of rats and mice.

INTRODUCTION: Rats and mice have been used to evaluate effects of natural and synthetic oestrogens. However, data about oestrogen's effects on haemostasis in rodents is very limited. The aim of this work was to standardize blood coagulation screening tests in adult male, female, and ovariectomized (Ovx) Wistar rats and CD1 mice in an effort to evaluate the influence of gender and species differences on haemostasis. MATERIALS AND METHODS: Values were obtained for the following haemostatic parameters: prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin clotting time (TT), and fibrinogen (FIB), through modifications of the conventional techniques used for human blood coagulation analysis. RESULTS: Both rats and mice showed gender intra-species and inter-species differences of high significance in PT, aPTT, TT, and FIB values. Intra-species differences were found in TT (+10% p<0.01) and FIB concentration (-21% p<0.001) between male and Ovx rats. Male vs. Ovx mice showed a TT difference of -20% (p<0.001). The main inter-species differences found were PT values of male rats vs. male mice (-39%) and female rats vs. female mice (-35%, both p<0.001). Female rats and mice aPTT values vs. those corresponding to Ovx animals showed differences of +15% and +32% (p<0.001), respectively. CONCLUSIONS: These data reveal the great importance of gender intra- and inter-species differences on the values of haemostatic screening tests, which should be taken into consideration when evaluating the effects of oestrogens and other drugs on the coagulation system.

Inhibitory effect of ethinylestradiol on coagulation factors in rats.

Epidemiological and experimental data have indicated the beneficial and adverse effects of estrogenic replacement therapy. In the present study, we explored the effect of ethinylestradiol (EE) and 17ß-estradiol (E2) on screening tests, prothrombin time (PT) and activated partial thromboplastin time (APTT), as well as the activity of coagulation factors (FVII, FX, FXI, and FXII) in male Wistar rats. Animals were injected subcutaneously during three consecutive days with EE or E2 (1, 3, 10, and 30 mg/kg) and propylene glycol (0.3 ml; vehicle, V). EE produced significant increments (P<0.05) on PT (8, 13, 15, and 10%) and APTT (32, 35, and 28%), whereas E2 did not show any effect. EE diminished the activity of factors VII (-10, -13, and -10%) and X (-10, -9, -15, and -14%; P<0.05), and E2 (1 mg/kg) produced a modest increment (8%; P<0.05) on FX only. E2 (10 mg/kg) showed a diminution of 9% (P<0.05), while EE did not produce any response on factor XII. EE diminished (-15, -14, -19, and -17%) but E2 augmented (10, 14, 24, and 24%) factor XI activity (P<0.05). Our findings suggest that EE and E2 produce different effects on coagulation and that EE seems to act across an inhibitory mechanism of coagulation factor activity in the present experimental model.

Contrasting effects of estradiol and 17 beta-aminoestrogens on blood clotting time in rats and mice.

Estrogens have been associated with thromboembolic events. Our group has described the anticoagulant effect of 17 beta-aminoestrogens in rodents, potentially new alternative estrogenic agents without thrombogenic risk. This work compares the contrasting effects of estradiol and the 17 beta-aminoestrogens (prolame, butolame, and pentolame) on blood clotting time. Ovariectomized CD1 mice received a single injection of 17beta-aminoestrogens, estradiol (20 to 80 mg/kg), or vehicle. Estradiol decreased blood clotting time from -10% to -25% (48 h; P<0.01) and 17 beta-aminoestrogens increased it, differing in latency (approximately 12 h; +48%, P<0.01) and duration (approximately 72 h +58%, P<0.01). In male Wistar rats, similar effects (pentolame +45%; estradiol -31%; P<0.01) were observed 48 h after five consecutive daily injections of 1000 microg/animal/day. The maximum procoagulant effect of estradiol was obtained after 72 h with 10 microg/animal/day (-45%; P<0.01). 17 Beta-aminoestrogens always produced opposite effects to those of estradiol on blood coagulation.

Estrogenic effects of 17 beta-aminoestrogens assessed in uteri of rats and mice.

Administration of exogenous estrogens has been associated with an increase of thromboembolic events. The 17 beta-aminoestrogens produce anticoagulant effects contrasting with the procoagulant effects of the natural occurring estradiol in rodents. This work compares the estrogenic effects induced by 17 beta-aminoestrogens prolame, butolame, pentolame, and estradiol in vivo models. Dose-response curves were performed using immature CD1 mice and Wistar rats. The animals were injected with estradiol or 17 beta-aminoestrogens (0.01 to 1000 microg/kg), or vehicle. The uterine wet and dry weights were determined. The 17 beta-aminoestrogens increased uterine weight in a dose-dependent manner. The uterotrophic effect produced by estradiol induced lower ED50 (6.5 and 4 microg/kg) and higher E(max) values (+523-350%) in mice as compared with those from the rat, indicating more susceptibility of the mice model. The 17 beta-aminoestrogens are partial estrogenic agonists with a relative uterotrophic effect of estradiol (100%) from 9-86%. Only the ED50 values of 17 beta-aminoestrogens in CD1 mice showed a direct correlation to the length of the amine group substitution in C-17 since their efficacy and potency were in the order: prolame>butolame>pentolame.

Ovariectomy differential influence on some hemostatic markers of mice and rats.

Rodent ovariectomy is an experimental method to eliminate the main source of sexual steroids. This work explored for the first time the ovariectomy temporal changes induced in the hemostatic coagulation markers: prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen concentration (FIB) along with uterine weight on adult female CD1 mice and Wistar rats. Uterine weight (Uw) was assessed before ovariectomy (control), and 1, 3, 5, 7, 9, 16, and 21 days after surgery. PT, aPTT, TT and FIB were estimated the same days, using reported standard techniques. Ovariectomy decreased Uw, since day 1; and from day 10 to 21 reached the lowest values for both species. After day 1, mice hemostatic parameters changed (PT +10%, P<0.05; aPTT +53%, P<0.05; TT -24%, P<0.05; FIB +67%, P<0.05). Rats showed significant changes only in TT and FIB (TT -13%, P<0.001; FIB +65%, P<0.001). Neither mice PT, aPTT and TT, recovered control values after 21 days. In the rats from day 5 to 16 aPTT diminished (18-23%, P<0.05) recovering to control values on day 21, TT after 9 days and PT on day 16. In both species, FIB returned to its control values after 9 days. Ovariectomy differentially altered the PT hemostatic parameter of mice and rats indicating a non-equivalence among both species behaviour for experimental studies of blood coagulation.

In vivo and in vitro estrogenic profile of 17ß-amino-1,3,5(10)estratrien-3-ol.

17ß-amino-1,3,5(10)estratrien-3-ol (17ßAE2), is the 17ß-aminoestrogens prototype possessing anticoagulant activity, contrasting with the procoagulant effects of 17ß-estradiol (17ßE2). Its estrogenicity profile has not been reported, and it was evaluated by uterotrophic assay, estrogen receptor binding affinity and its ability to induce gene transcription of the human estrogen receptor (hER)α mediated in a Saccharomyces cerevisiae yeast expression system. Additionally, 17ßAE2 and 17αAE2 were compared with 17ßE2 in HeLa cells co-transfected with expression vectors for hERα or hERß subtypes and for an estrogen-responsive reporter gene. Immature female CD1 mice and Wistar rats (21 days old) were treated for three days with 17ßAE2 (10-5000 µg/kg), 17ßE2 (0.001-1000 µg/kg) or vehicle (propylenglycol 10 ml/kg) and uterine weights were estimated. 17ßAE2 increased uterine weight in a dose-dependent manner. The effective dose (ED)50 uterine weight values: 17ßAE2=552 and 764 µg/kg (17ßE2=4.8 and 16 µg/kg) and their relative uterotrophic potency were 0.86 and 2.1 (17ßE2=100) in mice and rats, respectively. 17ßAE2 competed with [(3)H]E2 for the estrogen receptor. The 17ßAE2 relative binding affinities (RBAs) were: 0.074; Ki=2.2×10(-6)M (17ßE2=100; Ki=1.6×10(-9)M); 0.029 and Ki=3.8×10(-6)M (17ßE2=100; Ki=1.1×10(-9)M) for mice and rats uteri respectively. 17ßAE2 activated hERα-mediated ß-galactosidase transcription activity in the yeast system co-transfected with hERα gene. 17ßAE2 effective concentration (EC)50=1.82 µM (17ßE2=2.14 nM) with a relative potency of 0.12 (17ßE2=100). These transactivation effects were abolished by the antagonist fulvestrant (ICI 182,780), similarly to 17ßE2. 17ßAE2 and 17αAE2 bind with low relative affinity to hERα and hERß. Both induced hER-mediated reporter gene transactivation in a dose-response manner. The overall results provide evidence that 17ßAE2 has a weak agonist estrogenic action greatly mediated through the hERß and to a lesser extent the hERα at genomic level.

Changes on hemostatic parameters induced by 17beta-estradiol, ethinylestradiol, and the 17beta-aminoestrogen pentolame in the male Wistar rat.

Oral contraceptives containing estrogens increases the incidence of thromboembolic events. In contrast, administration of 17beta-aminoestrogens prolonged blood clotting time (BCT) in rodents. We studied the effect of estradiol (E(2)), ethinylestradiol (EE) and pentolame on some screening hemostatic tests. BCT was evaluated 24, 48, 72 and 96 h post-treatment. Rats received subcutaneously (s.c.) for five consecutive days E(2) (0.1-1000 microg), EE (1-1000 microg), pentolame (0.1-1000 microg), or vehicle (propyleneglycol 0.3 ml). At 48 h post-treatment E(2) (1000 microg) diminished BCT (32%, P<0.01), in contrast pentolame (1000 microg) augmented BCT by 41% (P<0.01). After 72 h, E(2) showed procoagulant effects with 10, 100 and 1000 microg doses (-45, -30, and -21%, respectively). Significant effects on BCT of EE were observed 72 h after with 1000 microg (-12%, P<0.05). Animals were treated s.c. for two consecutive days with E(2) (3mg/100g), pentolame (4 mg), or vehicle (0.1 ml). BCT, bleeding time (BT), platelet aggregation (PA), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen concentration were determined. E(2) produced a significant diminution on BCT (-20%) after 72 h whereas pentolame increased BCT from 24 to 96 h (62%, maximal response at 48 h). APTT and PT coagulation times of the groups treated with E(2) and pentolame were lengthened (33 and 29%; 16 and 24%, respectively; P<0.05). Fibrinogen concentration increased (115%, P<0.01) only in the pentolame-treated group. Pentolame and E(2) produced any effects on BT and PA compared with control groups, indicating that platelet function was not modified. Our results indicate that E(2), EE and pentolame affects the plasmatic phase of the hemostatic mechanism.

In vivo profile of the anticoagulant effect of 17ß-amino-1,3,5(10)estratrien-3-ol.

The anticoagulant activity of 17ß-amino-1,3,5(10)estratrien-3-ol (AE(2)) was established for the first time. Experiment 1: mice groups were treated with a single subcutaneous (s.c.) AE(2) injection (0.5, 1, 2, 4, and 8 mg/100 g BW) or vehicle (propylenglycol; 0.5 ml/100 g). After 24 h, AE(2) produced dose-dependent blood clotting time increases related to control, Emax=+121% (P<0.01) finishing the sixth day. Experiment 2: four groups received a single s.c. administration of AE(2) (4 or 8 mg/100g BW) or 17ß-estradiol (E(2); 3mg/100g BW) or vehicle. After 24 and 48 h post-administration, the times of blood clotting, prothrombin, thrombin, and activated partial thromboplastin and fibrinogen concentrations were assessed. Both AE(2) doses increased blood clotting and fibrinogen similarly, blood clotting time: 64, 94%; fibrinogen: 71, 107% (P<0.01). Prothrombin, activated partial thromboplastin and thrombin times, increased 13-15%, 27-55%, and 15-29%, respectively (P<0.01). Meanwhile E(2) decreased blood clotting 20% (P<0.01) and thrombin 23% (P<0.01) after 48 h. Experiment 3: for five consecutive days, mice received AE(2) or E(2) (0.1, 1, 10, 100, and 1000 µg/kg/day), or vehicle. Blood clotting time was assessed at 1, 2, 3, 4, 5, 8, and 11 days after treatment. AE(2) at all doses were anticoagulant for 2-3 days after administration whereas E(2) was procoagulant for 8-11 days. These opposite effects were: AE(2) Emax=+29%; E(2) Emax=-30%; (P<0.01). AE(2) is the parent compound of the 17ß-aminoestrogens, with the largest and longest anticoagulant effect until now reported.

Gender differences in response to chronic treatment with 17ß-oestradiol and 17ß-aminoestrogen pentolame on hemostasis in rats.

OBJECTIVES: This work evaluated chronic treatment with 17ß-oestradiol (E2) and 17ß-aminoestrogen pentolame (AEP) on prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen concentration (FIB). Male (M) and ovariectomized (Ovx) Wistar rats were used to explore gender differences in the pharmacological response. MATERIALS AND METHODS: Rats (n=12-18) were treated every third day during three months with E2 (1, 10, 100 µg/kg), AEP (1, 10, 100, 500 µg/kg) or vehicle (propylenglycol 1 ml/ kg). PT, aPTT, TT, and FIB were measured using standardized techniques. RESULTS: Chronic treatment with E2 in male rats increased PT (4-7%; P<0.05), decreased aPTT (9%; 100 µg/kg; P<0.05) and decreased TT (5% at 100 µg/Kg; P<0.05). Chronic treatment with E2 in ovariectomized female rats decreased PT (3-4%; P<0.05), did not induce significant changes on aPTT and decreased TT in a dose dependent manner (12-27%; P<0.05). Chronic treatment with AEP in male rats did not alter PT, increased aPTT in a dose dependent manner (5-16%; P<0.05), and decreased TT (5%; 500 µg/Kg; P<0.05) while in female ovariectomized rats it decreased PT (5-9%; P<0.05), increased aPTT (8-13%; P<0.05) and decreased TT (6-13%; P<0.05). E2 and AEP decreased FIB in M and Ovx animals. Decreases in FIB by E2 were more pronounced in male (15-18% P<0.05) than in ovariectomized rats (10-14% P<0.05). E2 showed more potency than AEP, lowering FIB at 1 and 10 µg/kg doses. Both estrogens decreased FIB in ovariectomized animals (E2, 10-14%, P<0.05; AEP, 9% P<0.05) and were reverted by increasing dosage. CONCLUSIONS: Gender influenced response to chronic treatment with E2 and AEP on hemostatic parameters. PT and aPTT were the most affected parameters, demonstrating non-equivalence in the pharmacological response of M and Ovx rats.

Spag16, an axonemal central apparatus gene, encodes a male germ cell nuclear speckle protein that regulates SPAG16 mRNA expression.

Spag16 is the murine orthologue of Chlamydomonas reinhardtii PF20, a protein known to be essential to the structure and function of the "9+2" axoneme. In Chlamydomonas, the PF20 gene encodes a single protein present in the central pair of the axoneme. Loss of PF20 prevents central pair assembly/integrity and results in flagellar paralysis. Here we demonstrate that the murine Spag16 gene encodes two proteins: 71 kDa SPAG16L, which is found in all murine cells with motile cilia or flagella, and 35 kDa SPAG16S, representing the C terminus of SPAG16L, which is expressed only in male germ cells, and is predominantly found in specific regions within the nucleus that also contain SC35, a known marker of nuclear speckles enriched in pre-mRNA splicing factors. SPAG16S expression precedes expression of SPAG16L. Mice homozygous for a knockout of SPAG16L alone are infertile, but show no abnormalities in spermatogenesis. Mice chimeric for a mutation deleting the transcripts for both SPAG16L and SPAG16S have a profound defect in spermatogenesis. We show here that transduction of SPAG16S into cultured dispersed mouse male germ cells and BEAS-2B human bronchial epithelial cells increases SPAG16L expression, but has no effect on the expression of several other axoneme components. We also demonstrate that the Spag16L promoter shows increased activity in the presence of SPAG16S. The distinct nuclear localization of SPAG16S and its ability to modulate Spag16L mRNA expression suggest that SPAG16S plays an important role in the gene expression machinery of male germ cells. This is a unique example of a highly conserved axonemal protein gene that encodes two protein products with different functions.

Antimetastatic, antineoplastic, and toxic effects of 4-hydroxycoumarin in a preclinical mouse melanoma model.

PURPOSE: We have previously reported that in vitro treatment of B16-F10 melanoma cells with 4-hydroxycoumarin (4-HC) decreases their metastatic potential. However, the antimetastatic efficacy of 4-HC in vivo is unknown; therefore, we investigated the antimetastatic and antineoplastic effects of 4-HC in a mouse melanoma model. Based on the findings, the immunomodulatory and toxic effects of 4-HC were also studied. METHODS: Experimental metastasis assay was performed in C57BL/6 mice that received 4-HC before intravenous injection of B16-F10 cells. Antitumor and antimetastatic efficacy of 4-HC was assessed in mice implanted subcutaneously with melanoma cells. Possible immunostimulant and toxic effects of 4-HC were studied in healthy mice. RESULTS: 4-HC reduced the number of experimental lung metastases. Moreover, 4-HC diminished primary tumor growth and increased survival time in mice bearing melanoma tumors. Treatments also decrease spontaneous lung metastases in the same animals. Different to other coumarins, the antitumor effect of 4-HC seems to be unrelated to immunostimulation, since plasma concentrations of cytokines remained unchanged. In contrast, toxic histological changes in nephrons and bronchiolar epithelium and a pronounced anticoagulant effect were found in 4-HC treated animals. CONCLUSIONS: These results show that 4-HC not only exhibit antimetastatic effect in vivo, but also effectively reduces tumor growth and improves survival, even when it produce toxic effects. Although the molecular mechanism of 4-HC actions needs to be further defined, our data suggest that 4-HC may lead to the development of agents that could be used as adjuvants in the therapy of melanoma.

In vivo and in vitro estrogen bioactivities of alkyl parabens.

The alkyl esters of p-hydroxybenzoic acid known as parabens (Pbens) are used as preservatives in food, pharmaceutical and cosmetic formulations. They have been reported as estrogenic. Here, we present evidence for the in vivo and in vitro bioactivities and receptor binding affinities of methylparaben (MePben), ethylparaben (EtPben), propylparaben (PrPben), and butylparaben (BuPben) compared with those of estradiol (E2). Estrogenicity was studied using the uterotrophic assay in immature (Im) and adult ovariectomized (Ovx) CD1 mice, and in immature female Wistar rats (IW). Animals were subcutaneously (sc) treated for three consecutive days with different molar equivalent doses ranging from 3.62 to 1086 micromol/kg body weight of Pbens, E2 (0.036 micromol/kg), or vehicle. Pbens increased uterine weight in Im and Ovx animals and their relative uterotrophic effect to E2 (100) (RUEE2) were from 34 to 91. The relative uterotrophic potencies related to E2 (100) (RUPE2) of these compounds were from 0.003 to 0.007. The E2 ED50 for CD1 animals able to increase the uterine weight was 7 microg/kg (0.9-55 confidence limits); and that of Pbens ranged from 18 to 74 mg/kg. In IW rats, the ED50 were from 33 to 338 mg/kg. All Pbens, except MePb, competed with [3H]E2 for the estrogen receptor binding sites. The uterotrophic effects of Pbens in Im mice have a positive correlation with the side-chain length of the ester group of these compounds. The E2 and Pbens relative binding affinities (RBA) and Ki values correlated to their estrogenic activity. The NOELs values for Pbens uterotrophic activity in Im were from 0.6 to 6.5 mg/kg per day; and Ovx from 6 to 55 mg/kg. The NOELs IW ranged from 16.5 to 70 mg/kg indicating that Im were more susceptible than Ovx and IW to these effects. The data shown here confirm the estrogenicity of Pbens.