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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Vienna, Austria, health workers took blood samples from 16 healthy, nonsmoking 19-35 year old women before and after they began using a combined oral contraceptive (OC) (Gynovin) (30 mcg ethinyl estradiol and 75 mcg gestodene) to assess the OC's effects on blood coagulation and fibrinolysis and the effect of the estrogen component on endothelial cells. Fibrinogen levels increased significantly after OC use (283 mg/dl vs. 342 mg/dl after the 1st treatment cycle; p .005). These levels remained significantly higher (326 mg/dl and 339 mg/dl after the 2nd and 3rd treatment cycles; p .005 and .05, respectively). Thrombin antithrombin III complex (TAT) and prothrombin fragment F1+2 levels increased just minimally during OC treatment. Levels of fibrin split-product D-dimer, plasma tissue plasminogen activator (t-PA) activity, and plasmin-antiplasmin (PAP) complexes were significantly higher during all OC treatment cycles than they were before treatment. Active plasminogen activator inhibitor (PAI-1) antigen, t-PA, and urokinase plasminogen activator antigen levels fell significantly after OC treatment and remained low during OC treatment. Experiments with the culture of human umbilical vein endothelial cells showed that ethinyl estradiol did not significantly affect the tissue factor content or surface thrombomodulin activity of these endothelial cells (i.e., hemostatic regulatory activities). It also did not change the secretion of the fibrinolytic components t-PA and PAI-1. None of the women developed thrombosis. Even though these findings did not clearly show OC-induced hemostatic activation in this relatively small group of women, clinical researchers should still determine activation markers to monitor the activation state of blood coagulation in certain OC users, such as obese women and those who smoke cigarettes.
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PMID:Studies on oral contraceptive-induced changes in blood coagulation and fibrinolysis and the estrogen effect on endothelial cells. 839 73

In healthy nondiabetic women, oral contraceptives (OCs) affect hemostatic function. In diabetic women, there is concern that they may also increase the risk of diabetic vascular complications. This study was designed to examine the balance between coagulation activity and fibrinolytic activity--an indirect measure of endothelial cell function--in women with insulin-dependent diabetes mellitus (IDDM) during long-term use of OCs. The study group included 11 young women with uncomplicated IDDM who were prescribed ethinyl estradiol 30 micrograms and gestodene 75 micrograms. Twelve other diabetic women not taking OCs constituted the control group. Hemostatic function was evaluated at entry and after 1,3,6, and 12 months. In women taking OCs, plasma levels of factor VII(c) increased, while fibrinogen levels did not change. Inhibition of coagulation was affected by increased levels of protein C, although plasma levels of antithrombin III and protein S remained stable. The antigen concentrations of tissue-type plasminogen activator and plasminogen activator levels themselves were unchanged. There was a proportionate increase in the concentrations of thrombin-antithrombin III complexes and D-dimer. None of the hemostatic variables changed significantly in the control group. We conclude that the balance between coagulation activity and fibrnolysis does not change during use of this OC. Our findings suggest that low-dose OCs induce a procoagulatory state that is compensated for by enhanced fibrinolytic activity.
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PMID:Balance of coagulation activity with fibrinolysis during use of oral contraceptives in women with insulin-dependent diabetes mellitus. 857 52

In Denmark, clinicians conducted clinical and metabolic evaluations on 17 healthy women, 21-26 years old, within the last 10 days of their menstrual cycle preceding intake with a triphasic oral contraceptive (OC) (ethinyl estradiol + norgestimate) and during the last 7 days of the sixth period of OC treatment. They aimed to examine the effect of proinsulin and insulin on fasting secretion of plasminogen activator inhibitor type 1 (PAI-1) and tissue plasminogen activator (t-PA). OCs have a well-defined effect on plasma levels of PAI-1 and t-PA. The clinical researchers also studied the antigen concentrations of PAI-1 and t-PA during slow and fast changes in proinsulin and insulin levels induced by oral and intravenous glucose tolerance tests. They did not find consistent correlations between fasting values of proinsulin, insulin, PAI-1, and t-PA either before or during OC treatment. During the glucose tolerance test induced hyperproinsulinemia and hyperinsulinemia and before OC treatment, PAI-1 and t-PA antigen levels fell (p 0.05). After 6 months of OC treatment, t-PA levels fell only during the oral glucose tolerance test (p 0.05) even though proinsulin and insulin responded similarly to the glucose loads. These findings suggest that neither proinsulin nor insulin regulate plasma levels of PAI-1 and t-PA in young healthy women regardless of OC use status.
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PMID:No influence of proinsulin and insulin on plasma levels of plasminogen activator inhibitor type 1 and tissue plasminogen activator in young women before and during intake of contraceptive steroids. 869 17

In Germany, 40 healthy women aged 18-30 with no contraindications to combined oral contraceptives (OCs) participated in a comparative study (2 pre-treatment cycles, 6 treatment cycles, and 1 post-treatment follow-up cycle). It aimed to assess the effect of the new low-dose monophasic OCs containing 20 mcg ethinyl estradiol (EE) and 75 mcg gestodene on the hemostatic system, the effect of reducing the EE dose from 30 mcg to 20 mcg, and the effect of this OC and another combined OC with 30 mcg EE on the fibrinolytic capacity at the vessel wall. Both OCs increased coagulatory and fibrinolytic parameters, except for isolated measurements, which remained within their normal ranges. The effect occurred as early as four days after beginning OC treatment. There was a general trend towards increased change during treatment. Within 14 days after stopping OC treatment, most parameters returned to baseline values. Protein C activity increased somewhat in both groups. Protein S activity was reduced in both groups, but the reduction was less in the 20 mcg EE group than in the 30 mcg EE group. There was a tendency towards greater plasminogen activator activity and lower plasminogen activator inhibitor activity in the 20 mcg EE group than in the 30 mcg EE group, suggesting increased fibrinolytic activity in the 20 mcg EE group. In both groups, an increase in the threshold of fibrinolytic inhibition occurred, but the increase was lower in the 20 mcg EE group. These findings suggest that both OC preparations have a balance effect on hemostasis, stimulating both pro-coagulant, anti-coagulant, and fibrinolytic activity. The 20 mcg EE OC tended to have a greater fibrinolytic activity than the 30 mcg EE OC, however.
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PMID:A comparative study of the effects of the hemostatic system of two monophasic gestodene oral contraceptives containing 20 micrograms and 30 micrograms ethinylestradiol. 883 83

Several clinical studies have demonstrated an inverse relationship between circulating levels of estrogen and tissue-type plasminogen activator (t-PA). The present study was designed to test the hypothesis that estrogens lower plasma levels of t-PA by increasing its clearance from the bloodstream. 17alpha-Ethinyl estradiol (EE) treatment resulted in a significant increase in the clearance rate of recombinant human t-PA in mice (0.46 mL/min in treated mice v 0. 32 mL/min in controls; P <.01). The clearance of endogenous, bradykinin-released t-PA in rats was also significantly increased after EE treatment (area under the curve [AUC], 24.9 ng/mL. min in treated animals v 31.9 ng/mL. min in controls; P <.05). Two distinct t-PA clearance systems exist in vivo: the low-density lipoprotein receptor-related protein (LRP) on liver parenchymal cells and the mannose receptor on mainly liver endothelial cells. Inhibition of LRP by intravenous injection of receptor-associated protein (RAP) as a recombinant fusion protein with Salmonella japonicum glutathione S-transferase (GST) significantly retarded t-PA clearance in control mice (from 0.41 to 0.25 mL/min; n = 5, P <.001) and EE-treated mice (from 0.66 to 0.35 mL/min; n = 5, P <.005), but did not eliminate the difference in clearance capacity between the 2 experimental groups. Similar results were obtained in mice in which LRP was inhibited via overexpression of the RAP gene in liver by adenoviral gene transduction. In contrast, administration of mannan, a mannose receptor antagonist, resulted in identical clearances (0.22 mL/min in controls and 0.24 mL/min in EE-treated mice). Northern blot analysis showed a 6-fold increase in mannose receptor mRNA expression in the nonparenchymal liver cells of EE-treated mice, whereas the parenchymal LRP mRNA levels remained unchanged. These findings were confirmed at the protein level by ligand blotting and Western blotting analysis. Our results demonstrate that EE treatment results in increased plasma clearance rate of t-PA via induction of the mannose receptor and could explain for the inverse relationship between estrogen status and plasma t-PA concentrations as observed in humans.
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PMID:Increased clearance explains lower plasma levels of tissue-type plasminogen activator by estradiol: evidence for potently enhanced mannose receptor expression in mice. 1043 21

The fundamental role of insulin resistance for metabolic changes linked to cardiovascular disease and type 2 diabetes is increasingly recognized. Oral contraceptives (OC) may affect insulin sensitivity, and a detailed characterization hereof, as well as the secondary effects on related metabolic systems, are relevant in the evaluation of the risk of developing vascular disorders or diabetes in OC users. We studied insulin sensitivity index (S(I)), glucose effectiveness (S(g)), and insulin response in young, healthy women by frequently sampled intravenous glucose tolerance tests before and after randomization to 6 months of treatment with ethinyl estradiol in triphasic combination with norgestimate (n = 17) or gestodene (n = 20). Measurements of fasting triglycerides and antigen concentrations of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) were also included. Both compounds increased fasting plasma insulin and reduced S(i) but did not affect S(g). The relationships between S(i) and insulin response were unchanged. No consistent correlation between insulin sensitivity and triglycerides, t-PA, or PAI-1 were demonstrated before or during treatment. We conclude that the treatments were followed by a compensated decrease in insulin sensitivity that was unrelated to changes in triglycerides, t-PA, or PAI-1 antigen.
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PMID:Metabolic and fibrinolytic response to changed insulin sensitivity in users of oral contraceptives. 1071 68

Oral estrogen administration decreases plasma levels of tissue-type plasminogen activator (tPA), which may be explained by a decrease in endothelial tPA synthesis, an increase in its hepatic clearance, or both. In the present study, we determined (1) differences between oral (ie, via the liver) ethinyl estradiol and transdermal (ie, systemic) 17beta-estradiol administration on plasma antigen levels of tPA and plasminogen activator inhibitor type-1 before and after 4 months of hormone administration and (2) effects on endothelial tPA synthesis, by measuring the local increase in plasma tPA during venous occlusion of the upper extremity. Thirty transsexual males (median age 32 years, range 20 to 44 years ) were randomly assigned to either oral ethinyl estradiol (n=15) or transdermal 17beta-estradiol (n=15); both treatments included the antiandrogen cyproterone acetate (CA). Ten males were treated with CA alone. Seventeen transsexual females (median age 27 years, range 18 to 37 years) were treated with intramuscular testosterone esters. Only oral ethinyl estradiol plus CA but neither transdermal 17beta-estradiol plus CA, nor oral CA, nor parenteral testosterone lowered plasma tPA and plasminogen activator inhibitor-1 (P<0.001 for both). tPA release during venous occlusion was not affected by oral ethinyl estradiol plus CA in males (P=0.52) or by parenteral testosterone in females (P=0.89). These data are consistent with a previous observation, in rodents, that the decrease in tPA after oral estrogen administration can be explained by an increase in hepatic tPA clearance, leaving endothelial tPA synthesis unchanged, and suggest that these mechanisms also explain the decrease in tPA in humans.
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PMID:Oral, but not transdermal, administration of estrogens lowers tissue-type plasminogen activator levels in humans without affecting endothelial synthesis. 1080 60

We have recently shown that the net release of tissue-type plasminogen activator (t-PA) antigen can be rapidly enhanced by the muscarinic receptor stimulation in healthy males. Since diabetes mellitus has been associated with endothelial dysfunction, the aim of the present study was to compare the endothelium-derived local net release of t-PA with vasodilation in response to muscarinic receptor stimulation by metacholine (Mch) and fluid shear stress in a group of postmenopausal women with non-insulin-dependent diabetes mellitus (NIDDM), and to elucidate the influence of estrogen on this process. Six postmenopausal women with NIDDM were in randomized order exposed to step-wise intra-arterial infusions of Mch (0.1-0. 8-4.0 microg/min) and nitroprusside (SNP; 0.5-2.5-10.0 microg/min). Forearm blood flow (FBF) was assessed by plethysmography. The infusions with Mch and SNP were repeated during simultaneous intra-arterial infusion of 17-beta estradiol (E; 20 ng/min). During placebo infusion, FBF increased significantly in response to Mch and SNP (p<0.001), but no differences between Mch and SNP were found. In parallel to the blood flow increase in response to Mch stimulation, the t-PA net release was increased over 30 times (p<0.001). Estrogen did not produce any change in blood flow or net release of t-PA at baseline or in response to either drug (Mch or SNP). The present study demonstrates a preserved endothelium-dependent vasodilation and stimulated tissue-type plasminogen activator release in NIDDM postmenopausal women in response to Mch stimulation. Acute intra-arterial infusion of 17-beta estradiol did not affect the vasodilation or the t-PA net release.
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PMID:Preserved tissue-type plasminogen activator release and endothelium-dependent vasodilation in postmenopausal women with NIDDM. 1098 20

Estrogen replacement therapy (ERT) has been found to be associated with increased cardiovascular risk in the first year after initiation of ERT. We compared the effects of oral and transdermal estradiol (E2) replacement therapy on markers of inflammation, coagulation and fibrinolysis in a randomized double-blind trial. Forty-three healthy women were randomized 6 weeks after surgically induced menopause to receive treatment with either oral or transdermal E2 over a period of 28 weeks. At baseline and after 28 weeks, levels of serum lipids and lipoproteins, and markers of coagulation, fibrinolysis and inflammation were determined. Among fibrinolytic parameters, oral E2 shortened euglobulin clot lysis time (P<0.05) and reduced tissue type plasminogen activator antigen (P=0.01) and plasminogen activator inhibitor activity (P<0.05). Among coagulation parameters, both routes of E2 replacement decreased fibrinogen levels (P=0.002 for oral and P=0.007 for transdermal E2). Oral E2 resulted in an increase in C-reactive protein (CRP) from 2.15 (0.71-4.05) to 3.41 (1.12-5.92) mg/l (P=0.04), while transdermal E2 showed no effect. Levels of serum amyloid A (SAA), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) did not change significantly after oral and transdermal E2. Oral E2 significantly improved the lipid profile, while transdermal E2 had a less pronounced effect. Both oral and transdermal E2 significantly reduced fasting glucose. Oral E2 was associated with a pro-inflammatory response, but at the same time improved fibrinolytic capacity, showed no pro-coagulatory effects, and acted beneficially on lipids and lipoproteins. There was no influence of transdermal E2 on markers of coagulation activation, fibrinolysis and inflammation, but it decreased fibrinogen levels significantly. Further studies are needed to explore the clinical relevance of these observations.
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PMID:Double blind, randomized study of estradiol replacement therapy on markers of inflammation, coagulation and fibrinolysis. 1273 95

We evaluated the association of hemostatic factors with insulin resistance in relation to reproductive hormones including FSH, estradiol, testosterone, and SHBG. SHBG was used to calculate the free estradiol index and free androgen index. We studied 3,200 women, aged 42-52 yr, in the Study of Women's Health Across the Nation, a prospective multiethnic study of the menopausal transition. We measured the hemostatic factors, fibrinogen, factor VIIc, tissue plasminogen activator (t-PA), and plasminogen activator inhibitor type 1 (PAI-1), as well as glucose and insulin to calculate insulin resistance. After adjustment for body mass index, site, and ethnicity, SHBG was correlated with PAI-1 (partial r = -0.30) and t-PA (partial r = -0.12). Although testosterone was associated with t-PA (partial r = 0.13) and PAI-1 (partial r = 0.07), free androgen index was strongly correlated with t-PA (partial r = 0.18) and PAI-1 (partial r = 0.26). SHBG modified the association of hemostatic factors with insulin resistance. Women with greater insulin resistance had lower SHBG and higher PAI-1. Estrogen measures were not associated with insulin resistance. The influence of sex hormones on hemostatic factors and insulin resistance is poorly understood. SHBG, which influences the amount of bioavailable hormone, significantly modified the association of PAI-1 and t-PA with insulin resistance. The longitudinal Study of Women's Health Across the Nation will help us discern whether this interaction contributes to heart disease and diabetes among postmenopausal women.
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PMID:Insulin resistance, hemostatic factors, and hormone interactions in pre- and perimenopausal women: SWAN. 1455 72


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