Discovery of varlaxins, new aeruginosin-type inhibitors of human trypsins.

Low-molecular weight natural products display vast structural diversity and have played a key role in the development of novel therapeutics. Here we report the discovery of novel members of the aeruginosin family of natural products, which we named varlaxins. The chemical structures of varlaxins 1046A and 1022A were determined using a combination of mass spectrometry, analysis of one- and two-dimensional NMR spectra, and HPLC analysis of Marfey's derivatives. These analyses revealed that varlaxins 1046A and 1022A are composed of the following moieties: 2-O-methylglyceric acid 3-O-sulfate, isoleucine, 2-carboxy-6-hydroxyoctahydroindole (Choi), and a terminal arginine derivative. Varlaxins 1046A and 1022A differ in the cyclization of this arginine moiety. Interestingly, an unusual α-D-glucopyranose moiety derivatized with two 4-hydroxyphenylacetic acid residues was bound to Choi, a structure not previously reported for other members of the aeruginosin family. We sequenced the complete genome of Nostoc sp. UHCC 0870 and identified the putative 36 kb varlaxin biosynthetic gene cluster. Bioinformatics analysis confirmed that varlaxins belong to the aeruginosin family of natural products. Varlaxins 1046A and 1022A strongly inhibited the three human trypsin isoenzymes with IC50 of 0.62-3.6 nM and 97-230 nM, respectively, including a prometastatic trypsin-3, which is a therapeutically relevant target in several types of cancer. These results substantially broaden the genetic and chemical diversity of the aeruginosin family and provide evidence that the aeruginosin family is a source of strong inhibitors of human serine proteases.

Acute exposure to resveratrol inhibits AMPK activity in human skeletal muscle cells.

AIMS/HYPOTHESIS: Recent studies have suggested resveratrol (RSV) as a new natural therapeutic agent to treat type 2 diabetes and lipid-induced insulin resistance. Here, we investigated whether RSV could reverse palmitate-induced insulin resistance in human primary muscle cells. METHODS: Myotubes obtained from six healthy men (54 ± 3 years (mean ± SE), BMI 25.0 ± 1.7 kg/m(2), fasting plasma glucose concentration (fP-glucose) 5.47 ± 0.09 mmol/l) were treated for 4 h with 100 µmol/l RSV and/or 0.2 mmol/l palmitate, and stimulated with or without 100 nmol/l insulin. Assays of glucose uptake, glycogen synthesis, palmitate oxidation, intracellular signalling and AMP-activated protein kinase (AMPK) activity were performed. RESULTS: RSV did not reverse palmitate-induced impairment of glucose metabolism. Surprisingly, RSV decreased glucose uptake and glycogen synthesis in human skeletal muscle cells. Palmitate oxidation and phosphorylation of AMPK and its downstream target acetyl-CoA carboxylase ß (ACCß) were inhibited by RSV, and RSV completely blocked the activity of AMPK isoform complexes α1/ß2/γ1 and α2/ß2/γ1 in in-vitro kinase activity assays. Endoplasmic reticulum (ER) stress was increased in response to RSV, as indicated by increased phosphorylation of eukaryotic initiation factor 2α (eIF2α) and increased expression of CCAAT/enhancer binding protein homologous protein (CHOP). CONCLUSIONS/INTERPRETATION: Acute exposure to RSV inhibits AMPK activity, fatty-acid oxidation and glucose metabolism in human myotubes.

Nitric oxide increases cyclic GMP levels, AMP-activated protein kinase (AMPK)alpha1-specific activity and glucose transport in human skeletal muscle.

AIMS/HYPOTHESIS: We investigated the direct effect of a nitric oxide donor (spermine NONOate) on glucose transport in isolated human skeletal muscle and L6 skeletal muscle cells. We hypothesised that pharmacological treatment of human skeletal muscle with N-(2-aminoethyl)-N-(2-hydroxy-2-nitrosohydrazino)-1,2-ethylenediamine (spermine NONOate) would increase intracellular cyclic GMP (cGMP) levels and promote glucose transport. METHODS: Skeletal muscle strips were prepared from vastus lateralis muscle biopsies obtained from seven healthy men. Muscle strips were incubated in the absence or presence of 5 mmol/l spermine NONOate or 120 nmol/l insulin. The L6 muscle cells were treated with spermine NONOate (20 micromol/l) and incubated in the absence or presence of insulin (120 nmol/l). The direct effect of spermine NONOate and insulin on glucose transport, cGMP levels and signal transduction was determined. RESULTS: In human skeletal muscle, spermine NONOate increased glucose transport 2.4-fold (p < 0.05), concomitant with increased cGMP levels (80-fold, p < 0.001). Phosphorylation of components of the canonical insulin signalling cascade was unaltered by spermine NONOate exposure, implicating an insulin-independent signalling mechanism. Consistent with this, spermine NONOate increased AMP-activated protein kinase (AMPK)-alpha1-associated activity (1.7-fold, p < 0.05). In L6 muscle cells, spermine NONOate increased glucose uptake (p < 0.01) and glycogen synthesis (p < 0.001), an effect that was in addition to that of insulin. Spermine NONOate also elicited a concomitant increase in AMPK and acetyl-CoA carboxylase phosphorylation. In the presence of the guanylate cyclase inhibitor LY-83583 (10 micromol/l), spermine NONOate had no effect on glycogen synthesis and AMPK-alpha1 phosphorylation. CONCLUSIONS/INTERPRETATION: Pharmacological treatment of skeletal muscle with spermine NONOate increases glucose transport via insulin-independent signalling pathways involving increased intracellular cGMP levels and AMPK-alpha1-associated activity.

Genetic and environmental components of interindividual variation in circulating levels of IGF-I, IGF-II, IGFBP-1, and IGFBP-3.

We assessed the magnitude of the genetic component in the variation of circulating levels of insulin-like growth factors I and II (IGF-I and IGF-II), and their binding proteins IGFBP-1 and IGFBP-3 by measuring their serum concentrations in 32 monozygotic and 47 dizygotic adult twin pairs of the same sex. The intrapair correlation for the IGF-I levels was r = 0.41 (P < 0.009) for monozygotic twins and r = 0.12 (P < 0.22) for dizygotic twins. For the IGF-II concentration the intrapair correlations were r = 0.66 (P < 0.0001) for the monozygotic and r = 0.34 (P < 0.01) for the dizygotic twins. No significant intrapair correlation was found for IGFBP-1 levels in either group. The correlations for IGFBP-3 concentration were r = 0.65 (P < 0.0001) and r = 0.23 (P < 0.06) for monozygotic and dizygotic twins, respectively. Women had higher IGF-II levels than men (635+/-175 vs. 522+/-144 microg/liter; P < 0.0001) and IGFBP-3 levels were also higher in women compared with men (5441+/-1018 vs. 4496+/-1084 microg/liter; P < 0.001). The proportion of variance attributable to genetic effects was 38% for the IGF-I concentration, 66% for the IGF-II concentration, and 60% for the IGFBP-3 concentration. No significant heritability was found for the IGFBP-1 concentrations. Our results show that, in adults, there is a substantial genetic contribution responsible for interindividual variation of the circulating levels of IGF-I, IGF-II, and IGFBP-3, but not for the IGFBP-1 levels.

Glycodelin: a reproduction-related lipocalin.

Glycodelin, a human lipocalin, is a major endometrial protein with at least two differentially glycosylated isoforms. Glycodelin-A (GdA) is purified from human mid-trimester amniotic fluid, where it is secreted from the decidualized endometrium. Glycodelin-S (GdS) is synthesized in the male reproductive tract, mainly in the seminal vesicles, and secreted into seminal plasma. These two glycodelin isoforms, glycosylated in a completely different manner, serve as a good model for studying the effects of glycosylation on protein function and physicochemical properties. We have reviewed here the structure, expression and biological functions of glycodelin.

Plasma acylation stimulating protein concentration and subcutaneous adipose tissue C3 mRNA expression in nondiabetic and type 2 diabetic men.

We studied the effect of an oral fat load on plasma acylation stimulating protein (ASP) concentrations in 9 lean healthy (age 59+/-2 years, body mass index [BMI] 23.2+/-0.4 kg/m(2); both mean+/-SEM), 9 obese nondiabetic (58+/-2 years, BMI 29.4+/-0.5 kg/m(2)), and 12 type 2 diabetic (60+/-2 years, BMI 29.6+/-1.0 kg/m(2)) men. Because ASP is a cleavage product of complement protein C3 (C3adesArg) and its secretion is regulated by insulin, we also examined the subcutaneous adipose tissue expression of C3 mRNA before and after a 240-minute euglycemic hyperinsulinemic clamp in a subgroup of these men. Plasma ASP concentration and adipose tissue C3 mRNA expression were higher in the obese groups than in the lean men. Plasma ASP concentration did not change significantly after the fat load. Fasting plasma ASP concentration and C3 mRNA expression were correlated negatively with insulin sensitivity and positively with the magnitude of postprandial lipemia in nondiabetic but not in type 2 diabetic men. The expression of C3 mRNA was not regulated by insulin. These data suggest that ASP is associated with whole-body glucose and lipid metabolism in nondiabetic individuals, whereas metabolic disturbances in diabetes may overcome the regulatory role of ASP in lipid and glucose metabolism.

Glycodelins.

Glycodelin is a major glycoprotein that is synthesized in the endometrium in response to progesterone and relaxin exposure. Endometrium-derived glycodelin-A has contraceptive and immunosuppressive properties. Glycodelin is absent from the endometrium during the fertile periovulatory phase, but is synthesized in this tissue during the peri-implantation phase and is abundant during the last week of the luteal phase. Changes in local and/or circulating glycodelin concentrations have been observed in women with reproductive disorders. The chemical modification of glycodelins has resulted in compounds with antiviral activity.

Insulin reduction with metformin increases luteal phase serum glycodelin and insulin-like growth factor-binding protein 1 concentrations and enhances uterine vascularity and blood flow in the polycystic ovary syndrome.

We hypothesized that hyperinsulinemia contributes to early pregnancy loss in the polycystic ovary syndrome by adversely affecting endometrial function and environment. Serum glycodelin, a putative biomarker of endometrial function, is decreased in women with early pregnancy loss. Insulin-like growth factor-binding protein-1 may also play an important role in pregnancy by facilitating adhesion processes at the feto-maternal interface. We studied 48 women with polycystic ovary syndrome before and after 4 weeks of administration of 500 mg metformin (n = 26) or placebo (n = 22) 3 times daily. Oral glucose tolerance tests were performed, and serum glycodelin and insulin-like growth factor-binding protein-1 were measured during the follicular and clomiphene-induced luteal phases of menses. In the metformin group, the mean (+/-SE) area under the serum insulin curve after glucose administration decreased from 62 +/- 6 to 19 +/- 2 nmol/L.min (P < 0.001). Follicular phase serum glycodelin concentrations increased 20-fold from 150 +/- 46 to 2813 +/- 1192 pmol/L (P < 0.001), and serum insulin-like-growth factor-binding protein-1 concentrations increased from 936 +/- 152 to 2396 +/- 300 pmol/L (P < 0.001). Similarly, luteal phase serum glycodelin concentrations increased 3-fold from 3434 +/- 1299 to 10624 +/- 1803 pmol/L (P < 0.001), and serum insulin-like growth factor-binding protein-1 concentrations increased from 1220 +/- 136 to 4916 +/- 596 pmol/L (P < 0.001). Uterine vascular penetration also increased in the metformin group, as did blood flow of spiral arteries, as demonstrated by a 20% decrease in the resistance index from 0.71 +/- 0.02 to 0.57 +/- 0.03 (P < 0.001). These variables did not change in the placebo group. We conclude that insulin reduction with metformin increases follicular and luteal phase serum glycodelin and insulin-like growth factor-binding protein-1 concentrations and enhances luteal phase uterine vascularity and blood flow in the polycystic ovary syndrome. These changes may reflect an improved endometrial milieu for the establishment and maintenance of pregnancy.

Insulin-like growth factor I is not a useful marker of prostate cancer in men with elevated levels of prostate-specific antigen.

High serum levels of insulin-like growth factor I (IGF-I) and low levels of IGF-binding protein-3 (IGFBP-3) have been shown to correlate with increased prostate cancer risk. To evaluate this, IGF-I, IGFBP-3, and prostate-specific antigen (PSA) were measured in serum from 665 consecutive men (179 with prostate cancer), aged 55-67 yr, with elevated serum prostate-specific antigen (PSA; > or = 4 microg/L) in a screening trial. Men in the highest quartile of IGF-I levels had an odds ratio (OR) for prostate cancer of 0.50 [95% confidence interval (CI) 0.26-0.97] when adjusting for serum IGFBP-3. IGFBP-3 itself was not significantly associated with prostate cancer risk (OR, 1.24; 95% CI, 0.68-2.24). Prostate volume was larger in men without than in those with prostate cancer (P < 0.001), and after adjustment for prostate volume, the negative association between serum IGF-I and prostate cancer risk was no longer significant (OR, 0.57; 95% CI, 0.28-1.16). In screen-positive men with elevated serum PSA, serum IGF-I is not a useful diagnostic test for prostate cancer, but it may be associated with benign prostatic hyperplasia and enlargement.

Leptin concentration in cord blood correlates with intrauterine growth.

Leptin is an adipocyte-derived peptide hormone regulating energy balance in experimental animals. Although the physiological function of leptin in humans is still unclear, its secretion is closely related to fat mass in adult humans. To examine how fetal growth correlates with leptin levels at birth, an umbilical cord venous blood sample was obtained at the delivery from 50 term newborn infants. Twenty-eight of the newborn infants had birth weights appropriate for gestational age (AGA; mean +/- SEM, 3362 +/- 90 g; relative birth weight, -0.08 +/- 0.2 SD), 9 were large for gestational age (birth weight, 4655 +/- 165 g; relative birth weight, 3.2 +/- 0.3 SD; P < 0.001 vs. AGA newborn infants), and 13 were small for gestational age (SGA; birth weight, 2385 +/- 69 g; relative birth weight, -2.2 +/- 0.08 SD; P < 0.001 vs. AGA newborn infants). Leptin concentrations were higher in large for gestational age (35.7 +/- 8.0 micrograms/L; P < 0.005), but lower in SGA (3.3 +/- 0.5 micrograms/L; P < 0.001) than in AGA infants (14.5 +/- 2.8 micrograms/L). When adjusted for differences in body weight, mean leptin levels were similar in the three newborn groups. Leptin concentration correlated closely with both absolute and relative birth weights (r = 0.71; P < 0.001 in both), with cord blood insulin concentration (r = 0.67; P < 0.001), and with placental weight (r = 0.60; P < 0.001). These data suggest that leptin is synthesized in utero, and that the circulating leptin concentration relates to the intrauterine growth pattern.

Insulin-independent glucose transport regulates insulin sensitivity.

The glucose transport proteins (GLUT1 and GLUT4) facilitate glucose transport into insulin-sensitive cells. GLUT1 is insulin-independent and is widely distributed in different tissues. GLUT4 is insulin-dependent and is responsible for the majority of glucose transport into muscle and adipose cells in anabolic conditions. We suggest the hypothesis that insulin resistance is dependent on whether glucose is entering through GLUT1 or GLUT4 and on the two functional compartments of glucose 6-phosphate formation within the cell. Glucose entering the muscle cell through GLUT4 and phosphorylated by hexokinase II is mainly directed to glycogen synthesis and glycolysis. If glucose is entering through GLUT1 and phosphorylated by hexokinase I, the glucose 6-phosphate so formed is available for all metabolic pathways, including the hexosamine pathway. Hexosamines have a negative feedback effect on GLUT4, and reduced GLUT4 activity decreases insulin-mediated glucose uptake. Thus, insulin-independent glucose transport through GLUT1 can meet the basal needs of the muscle cell. If glucose entrance through GLUT1 and the activation of the hexosamine pathway is abundant, it can decrease the insulin-mediated glucose transport through GLUT4 leading to insulin resistance.

Glycodelin and beta-lactoglobulin, lipocalins with a high structural similarity, differ in ligand binding properties.

Human glycodelin, a lipocalin with a high amino acid similarity to beta-lactoglobulins, appears as various glycoforms with different biological activities in endometrium (glycodelin-A) and seminal plasma (glycodelin-S). We found that the structures of these glycodelins and beta-lactoglobulin are similar. Despite this structural similarity, unlike beta-lactoglobulin, glycodelin-A binds neither retinoic acid nor retinol. It was impossible to detect any endogenous retinoids or steroids in any of the two purified glycodelins. Both their glycoforms share similar thermodynamic parameters of reversible denaturation suggesting that native folding of glycodelin-A and glycodelin-S is not influenced by the differences in glycosylation or by ligand binding.

Collagen formation and degradation increase during growth hormone therapy in children.

A comprehensive set of serum markers of collagen turnover and growth was investigated in a longitudinal study of short children during growth induced by growth hormone (hGH) treatment. The study comprised 18 prepubertal children with short stature who had no other current illness or continuous medication. The growth rates and endogenous GH secretions covered a continuum from subnormal to normal. Before treatment, the concentrations of carboxyterminal propeptide of type I procollagen (PICP), reflecting type I collagen formation, of carboxyterminal telopeptide of type I collagen (ICTP), a degradation product of type I collagen, of amino-terminal propeptide of type III procollagen (PIIINP), a marker for type III collagen formation, of alkaline phosphatase (AP), and of insulin-like growth factor binding protein-3 (IGFBP-3) were within the lower limits of normal. The median IGF-I concentration was lower than the reference. One week after the start of treatment, the serum concentrations of ICTP, PIIINP, and osteocalcin (OC), and the increments in ICTP, PIIINP, and IGF binding protein-3 (IGFBP-3) correlated with the subsequent height velocity. During the 12-month treatment, all markers were higher than those of age-matched references, but only the three collagen markers paralleled the changes in height velocity. In molar concentrations, ICTP increased less than PICP. Throughout the study period, the serum level of ICTP correlated with that of PIIINP, but not with that of PICP. The findings suggest that during hGH treatment, linear body growth is closely associated with collagen formation and degradation.

Comparative studies on the regulation of insulin-like growth factor-binding protein-1 (IGFBP-1) and sex hormone-binding globulin (SHBG) production by insulin and insulin-like growth factors in human hepatoma cells.

Production of insulin-like growth factor-binding protein-1 (IGFBP-1) by the liver is efficiently inhibited by insulin both in vivo and in vitro. Consequently, serum IGFBP-1 concentration reflects insulin bioactivity in portal vein. Sex hormone-binding globulin (SHBG) is another insulin-regulated liver-derived protein that has appeared promising in detecting individuals with portal hyperinsulinemia. We compared the regulation of IGFBP-1 and SHBG production by insulin and insulin-like growth factors (IGF-I and IGF-II) in human hepatoma cell cultures. Insulin equipotently inhibited IGFBP-1 and SHBG production, with maximal decrease in culture medium concentrations being about 35% for both proteins during 48 h of culture in serum-free medium. IGF-I and IGF-II also inhibited the IGFBP-1 and SHBG levels. We conclude that IGFBP-1 and SHBG are equally sensitive to ambient insulin concentrations in human hepatoma cell cultures, and the production of both proteins is also attenuated by the IGFs.

Factors regulating insulin-like growth factor binding protein-3 secretion from human hepatoma (HepG2) cells.

Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) is a growth hormone (GH) dependent carrier of the IGFs in human serum. Apart from GH regulation the hormonal control of IGFBP-3 production is not well established and although the liver is considered to be the main source of circulating IGFBP-3, there are no in vitro studies of the effect of both insulin and IGFs on the IGFBP-3 produced in human hepatoma cells. The effect of sex hormones as well as cortisol has not been studied. To elucidate this we performed cell culture studies on HepG2 cells in the presence of various effectors. Insulin, IGF-I and IGF-II brought about a 1.5-2-fold enhancement of IGFBP-3 release at 7.5-30 nM concentrations. In contrast, cortisol decreased IGFBP-3 secretion by 30-40% whereas estradiol, tamoxifen and testosterone had no effect at physiological concentrations. We conclude that, in addition to GH, also insulin, IGF-I and IGF-II and glucocorticoids can modulate IGFBP-3 secretion by human hepatoma cells.

Concentration of the complement activation product, acylation-stimulating protein, is related to C-reactive protein in patients with type 2 diabetes.

Type 2 diabetes is characterized by increased acute phase serum proteins. We wanted to study how these proteins are related to complement activation in type 2 diabetes and how improvement of glycemic control affects them or complement activation. A total of 29 type 2 diabetic patients (age, 55.2 +/- 1.8 years, glycosylated hemoglobin [HbA(1c)] 8.9% +/- 0.2%, body mass index [BMI] 30.9 +/- 0.8 kg/m(2), duration 5.9 +/- 1.3 years) participated in the study. They were previously treated either with diet alone or in combination with 1 oral antihyperglycemic medication. After a period of at least 4 weeks run-in on diet only, the patients were randomized to pioglitazone, glibenclamide, or placebo. Blood samples were taken before the treatments and at the end of the 6-month therapy. Basal C-reactive protein (CRP) level was related to acylation-stimulating protein (ASP) concentration (r =.55, P <.01), and many acute phase serum protein concentrations were associated with each other. The treatment reduced HbA(1c) level in the pioglitazone (from 9.1 +/- 0.3% to 8.0 +/- 0.5%, P <.05) and glibenclamide (from 8.9 % +/- 0.3% to 7.7% +/- 0.2%, P <.05) groups. Glibenclamide treatment was associated with a reduction in alpha-1-antitrypsin (P <.05), ceruloplasmin (P <.01), and complement C3 protein (C3) (P <.05). Although ASP did not change significantly in any of the treatment subgroups, in the whole patient population, the change in HbA(1c) during the treatments correlated positively with the change in ASP, (r =.43, P <.05). The changes in many acute phase serum proteins and ASP were related to each other. In conclusion, (1) inflammatory factors and complement activation are associated in patients with type 2 diabetes, and (2) changes in hyperglycemia are related to changes in the concentration of the complement activation product, ASP.

Leptin during and after preeclamptic or normal pregnancy: its relation to serum insulin and insulin sensitivity.

Hyperleptinemia may be part of the insulin resistance syndrome. We studied serum leptin in preeclampsia, which is an insulin-resistant state, and sought associations between leptin and insulin or insulin sensitivity during and after pregnancy. Twenty-two proteinuric preeclamptic women and 16 normotensive controls were studied during the third trimester. Leptin was higher in preeclampsia (mean +/- SE, 34.6 +/- 3.9 v 20.0 +/- 3.3 microg/L, P = .002) and correlated directly with the level of proteinuria (r = .47, P = .03) and normal pregnancy (r = .52, P = .04), whereas insulin sensitivity as assessed by an intravenous glucose tolerance test showed no relationship to leptin. Leptin was 19.0 +/- 3.6 microg/L in 14 preeclamptic women and 10.1 +/- 2.0 microg/L (P = .11) in 11 controls 3 months after delivery. Leptin correlated directly with insulin both in preeclamptic puerperal women (r = .63, P = .02) and in controls (r = .81, P = .003). Leptin and insulin sensitivity correlated only in preeclamptic puerperal women (r = -.59, P = .02). In conclusion, (1) serum leptin is elevated in preeclampsia, (2) insulin is an important determinant of serum leptin in preeclamptic and normotensive women both during pregnancy and in the puerperium, and (3) hyperleptinemia may be part of the insulin resistance syndrome also in women with prior preeclampsia.

Effect of marathon run on serum IGF-I and IGF-binding protein 1 and 3 levels.

Acute physical exercise increases growth hormone (GH) secretion, and GH regulates the expression of insulin-like growth factor I (IGF-I) and IGF-binding protein (IGFBP) 3. IGFBP-1 is a local modulator of IGF activity with rapid dynamic regulation that is downregulated by insulin. The IGF system mediates the metabolic actions of GH, and possibly it regulates glucose metabolism. We hypothesize that strenuous exercise causes changes in the IGF system. We studied the effects of the marathon run on the circulating levels of IGF-I, IGFBP-1, IGFBP-3, and insulin in 23 participants. Immediately after the run, the most striking change was an 11.6-fold median increase in serum IGFBP-1 level (from 63.7 +/- 50.5 to 736 +/- 408 micrograms/l; P < 0.001). Because the insulin level remained unchanged, the elevation of serum IGFBP-1 level cannot be explained by changes in insulin. One day after the run, the IGFBP-1 level had returned to baseline. The physiological role of this increment could be the inhibition of hypoglycemic effects of IGF-I and/or regulation of glucose availability to the muscles. The changes in IGF-I and IGFBP-3 levels were less dramatic: the IGF-I and IGFBP-3 levels were lower 1 and 3 days after the run. This report provides an important basis for authentic effects of strenuous exercise on the IGF-system.

Endometrial expression of glycodelin in women with levonorgestrel-releasing subdermal implants.

OBJECTIVE: To determine whether subdermal levonorgestrel implants induce endometrial expression of glycodelin. DESIGN: Cross-sectional, blinded study. SETTING: University clinic. PATIENT(S): One hundred and eight women with subdermal implants and 19 postmenopausal women. INTERVENTION(S): Endometrial biopsies, curettages, and hysterectomies. MAIN OUTCOME MEASURE(S): Endometrial glycodelin expression was examined through immunohistochemistry, in situ hybridization, and morphologic endometrial dating. RESULT(S): Overall, 80% of the endometrial specimens obtained from women with subdermal levonorgestrel implants stained positive for glycodelin. Endometrial morphology of these women showed proliferative (71%), inactive/weakly proliferative (19%), menstrual or regenerating (6.5%), and other patterns (2.8%). Of these, 79%, 71%, 100%, and 100% were glycodelin positive, respectively. Nineteen specimens were obtained during the midcycle when glycodelin is not normally expressed: of these, 89% stained positive for glycodelin. Implant-related amenorrhea was associated with endometrial glycodelin expression in 58% of the women, whereas the endometrium specimens obtained from women with postmenopausal hypoestrogenic amenorrhea contained no detectable glycodelin. CONCLUSION(S): Subdermal levonorgestrel implant use is often associated with endometrial expression of glycodelin. Because glycodelin has been shown to inhibit sperm-egg binding, the induction of glycodelin may contribute to the contraceptive activity of the implant.

Estradiol increases the production of sex hormone-binding globulin but not insulin-like growth factor binding protein-1 in cultured human hepatoma cells.

OBJECTIVE: To study the effects of E2 on insulin-like growth factor binding protein-1 (IGFBP-1) and sex hormone-binding globulin (SHBG) production with cultured human HepG2 hepatoma cells. DESIGN: Experimental cell culture. SETTING: Academic medical center. PATIENT(S): None. INTERVENTION(S): Addition of E2 to cell culture medium. MAIN OUTCOME MEASURE(S): Intracellular and released concentrations of IGFBP-1 and SHBG. RESULT(S): Estradiol did not affect the intracellular or extracellular IGFBP-1 concentration, whereas the intracellular SHBG concentration increased significantly in response to 0.5-2.5 microM of E2. CONCLUSION(S): Whereas the two binding proteins share a number of regulatory factors, their regulation by E2 is dissimilar in human hepatoma cells. Estradiol does not affect the intracellular or secreted IGFBP-1 concentration, but it does increase the production of SHBG.