The effect of high-dose vitamin D on bone mineral density and bone turnover markers in postmenopausal women with low bone mass--a randomized controlled 1-year trial.

UNLABELLED: Vitamin D is widely used in osteoporosis treatment, although the optimal dose is not known. This 1-year clinical study among 297 women aged 50-80 years old showed that a vitamin D(3) dose of 6,500 IU/day was not better than the standard dose of 800 IU/day in improving bone mineral density (BMD) in the hip and spine. INTRODUCTION: The purpose of this study was to determine whether a high dose of vitamin D(3) was better than the standard dose in improving BMD and reducing bone turnover in postmenopausal women with reduced bone mass. METHODS: The study was a 1-year randomized double-blind controlled trial comparing high-dose vitamin D(3) with the standard dose. Postmenopausal women (n = 297) with a BMD T-score ≤ -2.0 in either lumbar spine (L2-4) or total hip were included and randomized to 6,500 IU vitamin D(3)/day (20,000 IU twice per week + 800 IU/day) or 800 IU vitamin D(3)/day (placebo twice per week + 800 IU/day). Both groups were given 1,000 mg elemental calcium/day. The primary endpoint was a change in BMD in total hip and lumbar spine (L2-4). RESULTS: After 1 year, serum 25-hydroxyvitamin D (25(OH)D) increased [mean (SD)] from 71 (23) to 185 (34) nmol/l and from 71 (22) to 89 (17) nmol/l in the high- and standard-dose vitamin D groups, respectively. BMD at all measurement sites was unchanged or slightly improved with no significant differences between the groups. Although bone turnover was reduced in both groups, the more pronounced reduction in serum levels of the bone formation marker P1NP in the standard-dose group may indicate that this treatment was more efficient. Adverse events did not differ between the groups. CONCLUSIONS: One year treatment with 6,500 IU vitamin D(3)/day was not better than 800 IU/day regarding BMD in vitamin D-replete postmenopausal women with reduced bone mass and was less efficient in reducing bone turnover.

Glycated hemoglobin in diagnosis of diabetes mellitus and pre-diabetes; validation by oral glucose tolerance test. The Tromsø OGTT Study.

BACKGROUND: Glycated hemoglobin (HbA(1c)) 6.5% has recently been recommended by the World Health Organization (WHO) and the American Diabetes Association (ADA) as an alternative diagnostic criterion for diabetes mellitus (DM). AIM: To evaluate HbA(1c) as an alternative to oral glucose tolerance test (OGTT) for diagnosis of DM and pre-diabetes and to find the optimal HbA(1c) cut-off points for DM and pre-diabetes in our population. SUBJECTS AND METHODS: The subjects were recruited from the Tromsø Study, performed for the 6th time in 2007-2008 with 12,984 participants. All subjects with HbA(1c) in the range 5.8-6.9% and a random sample of subjects with levels 5.3-5.7% were invited to an OGTT. RESULTS: Among 3476 subjects who completed the OGTT, 199 were diagnosed with DM. The best sensitivity (69.8%) and specificity (81.8%) were found at HbA(1c) 6.2%. For HbA(1c) 6.5% we found a sensitivity of 34.7% and specificity 97.1%. The best cut-off points for impaired fasting glucose (no.=314) and impaired glucose tolerance (no.=404) were found at HbA(1c) 5.9% and 6.0%, respectively. Pre-diabetes detected only by OGTT was associated with worse metabolic characteristics than pre-diabetes detected only by HbA(1c). CONCLUSIONS: The optimum HbA(1c) cutoff point for DM in our population was lower than that proposed by WHO and ADA. To establish more precisely the HbA(1c) levels predictive of micro- and macro-vascular complications, long-term prospective studies are needed. Population- specific optimum cut-off points may be necessary.

High serum 25-hydroxyvitamin D concentrations are associated with a favorable serum lipid profile.

BACKGROUND/OBJECTIVES: Low serum 25-hydroxyvitamin D (25(OH)D) concentrations are related to increased mortality. One possible explanation could be an association between serum 25(OH)D and serum lipids. SUBJECTS/METHODS: The study was performed at the University of Tromsø, Northern Norway. In total, 8018 nonsmoking and 2087 smoking subjects were included in a cross-sectional study performed in 2008, and 1762 nonsmoking and 397 smoking subjects in a longitudinal study from 1994/1995 to 2008. Nonfasting serum 25(OH)D, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C ratio and triacylglycerol (TAG) were measured. RESULTS: After adjustment for gender, age, sample month and body mass index in the cross-sectional study, there was a significant increase in serum TC, HDL-C and LDL-C, and a significant decrease in serum LDL-C/HDL-C ratio and TAG across increasing serum 25(OH)D quartiles. For serum HDL-C and TAG in nonsmokers the differences between the means for the highest and lowest serum 25(OH)D quartiles were 6.0 and 18.5%, respectively. In the longitudinal study, an increase in serum 25(OH)D was associated with a significant decrease in serum TAG. CONCLUSIONS: There is a cross-sectional association between serum 25(OH)D and serum lipids, and a longitudinal association over 14 years between serum 25(OH)D and TAG, which may contribute to explain the relation between low serum 25(OH)D concentrations and mortality.

Baseline serum 25-hydroxyvitamin D concentrations in the Tromsø Study 1994-95 and risk of developing type 2 diabetes mellitus during 11 years of follow-up.

AIMS: We wanted to test the hypothesis that low serum 25-hydroxyvitamin D (25(OH)D) concentrations are associated with increased risk of developing Type 2 diabetes mellitus (DM) in a population-based cohort during 11 years of follow-up. METHODS: The analyses included 4157 non-smokers and 1962 smokers from the Tromsø Study 1994-95 without diabetes at baseline. Subsequent Type 2 DM was defined using a hospital journal-based end-point registry, completed through the year 2005. Participants were allocated into quartiles of serum 25(OH)D within each month to account for seasonal variation, and serum 25(OH)D values both as a continuous variable and in quartiles were used in Cox regression models. The analyses were stratified by smoking. Adjustments were made for age, sex, body mass index (BMI), physical activity and, in non-smokers, former smoking. RESULTS: Type 2 DM was registered in 183 non-smoking and 64 smoking participants. Using the fourth (highest) quartile of serum 25(OH)D as the reference, non-smoking participants in the third, second and first quartiles had age- and sex-adjusted hazard ratios (95% confidence intervals) of incident Type 2 DM of 1.00 (0.62-1.61), 1.50 (0.97-2.31) and 1.89 (1.25-2.88), respectively, whereas the corresponding values for smokers were 1.79 (0.77-4.19), 2.33 (1.02-5.35) and 2.68 (1.18-6.08). Adjustment for BMI attenuated the hazard ratios, and they were no longer significant. CONCLUSIONS: Baseline serum 25(OH)D was inversely associated with subsequent Type 2 DM in a population-based 11 year follow-up study, but not after adjustment for BMI. Randomized trials are needed to define the possible role of serum 25(OH)D status, and thereby the role of supplementation, in the prevention of Type 2 DM.

No improvement in cardiovascular risk factors in overweight and obese subjects after supplementation with vitamin D3 for 1 year.

BACKGROUND AND AIM: Cross-sectional studies indicate vitamin D to be of importance for glucose tolerance, blood pressure and serum lipids, but whether supplementation with vitamin D would improve cardio-vascular risk factors is not known. DESIGN AND SETTING: The study was a 1 year, double blind placebo-controlled intervention trial performed at the University Hospital of North Norway from November 2005 to October 2007. Subjects. A total of 438 overweight or obese subjects, 21-70 years old, were included and 330 completed the study. INTERVENTIONS: The subjects were randomized to vitamin D (cholecalciferol, vitamin D(3)) 40 000 IU per week (DD group), vitamin D 20 000 IU per week (DP group), or placebo (PP group). All subjects were given 500 mg calcium daily. MAIN OUTCOME MEASURES: Fasting serum lipids and blood pressure were measured and an oral glucose tolerance test performed at start and end of the study. RESULTS: At baseline the mean serum 25(OH)D levels were 58 nmol L(-1) (all subjects) and increased to 140 and 101 nmol L(-1) in the DD and DP groups, respectively. No significant differences were found between the three groups regarding change in measures of glucose metabolism or serum lipids. In the DP group, there was a slight but significant increase in systolic blood pressure compared with the placebo group. CONCLUSIONS: Our results do not support a positive effect of vitamin D on glucose tolerance, blood pressure or serum lipids. Further studies in subjects with low serum 25(OH)D levels combined with impaired glucose tolerance, hypertension or dyslipidaemia are needed.

Supplementation with cholecalciferol does not result in weight reduction in overweight and obese subjects.

OBJECTIVE: Investigate whether cholecalciferol supplementation leads to weight loss in overweight and obese adults. DESIGN: Randomized double blind clinical trial with 20,000 IU cholecalciferol twice a week, or 20,000 IU once a week plus placebo, or placebo twice a week, for 12 months. All subjects were given 500 mg calcium supplementation. METHODS: Four hundred and forty five healthy, overweight, and obese men and women (age 21-70 years, body mass index (BMI) 28.0-47.0 kg/m(2)). Body weight, fatness, and fat distribution parameters were measured by dual-energy X-ray absorptiometry and anthropometry, blood samples and 24-h urinary samples were collected. RESULTS: At baseline, there were no significant differences between the groups, but there was a significant inverse relation between serum 25-hydroxyvitamin D (25(OH)D) levels and BMI, and a significant positive association between calorie intake and BMI. Three hundred and thirty four subjects completed the study. During the study, there was no significant change in weight, waist-to-hip ratio (WHR) or percentage body fat in any of the groups, nor between them. Parathyroid hormone decreased and 25(OH)D increased significantly in both groups receiving cholecalciferol, and serum levels of 25(OH)D stabilized after 3 months. Serum calcium was unchanged in all groups. Urinary calcium excretion increased in all groups, but there was no significant difference between the groups. Weekly dosage of 20,000-40,000 IU cholecalciferol for 12 months was associated with a low risk of adverse effects, at least in overweight and obese adults living at latitude 70 degrees N. CONCLUSION: Significant weight reduction in overweight and obese subjects is unlikely to occur with cholecalciferol supplementation.

Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial.

OBJECTIVES: The objective of the present study was to examine the cross-sectional relation between serum 25-hydroxyvitamin D [25-(OH) D] levels and depression in overweight and obese subjects and to assess the effect of vitamin D supplementation on depressive symptoms. DESIGN: Cross-sectional study and randomized double blind controlled trial of 20,000 or 40,000 IU vitamin D per week versus placebo for 1 year. SETTING: A total of 441 subjects (body mass index 28-47 kg m(-2), 159 men and 282 women, aged 21-70 years) recruited by advertisements or from the out-patient clinic at the University Hospital of North Norway. MAIN OUTCOME MEASURES: Beck Depression Inventory (BDI) score with subscales 1-13 and 14-21. RESULTS: Subjects with serum 25(OH)D levels < 40 nmol L(-1) scored significantly higher (more depressive traits) than those with serum 25(OH)D levels > or = 40 nmol L(-1) on the BDI total [6.0 (0-23) versus 4.5 (0-28) (median and range)] and the BDI subscale 1-13 [2.0 (0-15) versus 1.0 (0-29.5)] (P < 0.05). In the two groups given vitamin D, but not in the placebo group, there was a significant improvement in BDI scores after 1 year. There was a significant decrease in serum parathyroid hormone in the two vitamin D groups without a concomitant increase in serum calcium. CONCLUSIONS: It appears to be a relation between serum levels of 25(OH)D and symptoms of depression. Supplementation with high doses of vitamin D seems to ameliorate these symptoms indicating a possible causal relationship.

Testosterone treatment in elderly men with subnormal testosterone levels improves body composition and BMD in the hip.

Our intention was to examine if subnormal testosterone levels in older men were associated with a reduction in quality of life and physical and mental health, and secondly to examine if testosterone treatment could improve these conditions. We performed a nested case-control study and a 1-year testosterone intervention study. Men with subnormal testosterone had significantly higher weight, fat mass and abdominal adipose tissue. They also had significantly higher glucose and insulin levels, and they had higher triglyceride levels. Testosterone treatment had a large impact on body composition with reduced fat mass and abdominal adipose tissue and increased fat-free mass, but it did not affect weight and glucose and lipid metabolism. Bone mineral density in the hip was significantly higher after the testosterone treatment. Older men with subnormal testosterone levels had an unfavorable metabolic profile. Testosterone treatment improved body composition, but it did not reverse the unfavorable metabolic profile.

Insulin sensitivity in subjects with secondary hyperparathyroidism and the effect of a low serum 25-hydroxyvitamin D level on insulin sensitivity.

To investigate the relation between secondary hyperparathyroidism (SHPT) and insulin sensitivity, 15 subjects with SHPT (serum PTH >6.4 pmol/l, serum calcium <2.40 mmol/l, and normal serum creatinine) and 15 control subjects were investigated with an oral glucose tolerance test (OGTT) and a 3-h hyperglycemic clamp. Body composition was measured with dual-energy X-ray absorptiometry. No differences were found between the SHPT and control groups on any indices of glucose or insulin metabolism. However, when dividing the 30 subjects in the upper and lower halves according to serum 25-hydroxyvitamin D levels (<59 and >58 nmol/l), those in the lower half had significantly higher 2-h serum insulin value at the OGTT, significantly higher insulin secretion during the last hour of the clamp, and significantly lower insulin sensitivity index (ISI; glucose infusion rate/insulin secretion during the last hour of the clamp). In a multiple linear regression analysis correcting for age, gender, and body mass index (BMI), the serum 25-hydroxyvitamin D level was significantly and positively associated with the ISI. The amounts of total body and truncal fat were negatively and significantly associated with the ISI, whereas no association between measures of lean body mass were associated with insulin secretion or sensitivity.

Blood pressure in relation to serum thyrotropin: The Tromsø study.

It appears to be an association between hypothyroidism and hypertension. However, the relation between thyroid function and blood pressure within the normal serum thyrotropin (TSH) range is uncertain. In the fifth Tromsø study, which is a population-based health survey, serum TSH and blood pressure were measured. This gave us the opportunity to test the hypothesis of a relation between serum TSH and blood pressure within the normal serum TSH range. In all 5872 subjects (2623 male subjects) not using blood pressure or thyroxine medication were included in the present study. Within the normal serum TSH range (0.20-4.00 mIU/l), there was a significant and positive relation between serum TSH and both systolic and diastolic blood pressure. Within this range, and adjusted for age, body mass index and smoking status, the systolic blood pressure was 1.4 mm Hg and the diastolic 1.6 mm Hg higher in male subjects in the highest versus those in the lowest serum TSH quartile. The corresponding differences in the female subjects were 4.0 and 2.7 mm Hg, respectively. When dividing this cohort in those with systolic (>160 mm Hg) and diastolic (>95 mm Hg) hypertension, serum TSH was higher in the hypertensive subjects, but the differences were only statistically significant for diastolic hypertension (serum TSH 1.88+/-0.82 versus 1.69+/-0.74 mIU/l for male subjects, and 1.79+/-0.78 versus 1.63+/-0.75 mIU/l for female subjects, P < 0.05). In conclusion, there is a modest, but significant positive association between serum TSH and blood pressure within the normal serum TSH range.

Serum lipid levels in relation to serum thyroid-stimulating hormone and the effect of thyroxine treatment on serum lipid levels in subjects with subclinical hypothyroidism: the Tromsø Study.

OBJECTIVE: To evaluate the relation between serum thyroid-stimulating hormone (TSH) and lipids. DESIGN: Cross-sectional epidemiological study, nested case-control study, and a placebo-controlled double-blind intervention study. METHODS: In the 5th Tromsø study serum TSH, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were measured. Subjects with subclinical hypothyroidism (SHT) and a matching control group were re-examined and apolipoprotein A1 (Apo A1) and apolipoprotein B (Apo B) were also measured. Subjects with SHT were included in an intervention study with thyroxine supplementation for 1 year. RESULTS: A total of 5143 subjects from the 5th Tromsø study were included. A significant and positive correlation between serum TSH levels and serum TC and LDL-C levels were found in both genders. However, in the females this did not reach statistical significance after adjusting for age and BMI. The serum LDL-C were significantly higher and the Apo A1 levels significantly lower in 84 SHT subjects compared with 145 controls, and in the SHT females the TC levels were also significantly elevated. In the intervention study (32 subjects given thyroxine and 32 subjects given placebo), we observed a significant reduction in the Apo B levels after thyroxine medication. In those that at the end of the study had serum TSH levels in the range 0.2-2.0 mIU L(-1), the serum TC and LDL-C levels were also significantly reduced. CONCLUSIONS: There is a positive association between serum TSH levels and TC and LDL-C levels. These lipid levels are reduced with thyroxine treatment in subjects with SHT.

Serum parathyroid hormone (PTH) levels in smokers and non-smokers. The fifth Tromsø study.

OBJECTIVE: Smoking is associated with reduced bone density and calcium absorption, and reduced serum levels of vitamin D. A compensatory increase in serum parathyroid hormone (PTH) would therefore be expected as a result of an altered calcium balance. However, reports on PTH levels in smokers are conflicting. As serum PTH levels give important information on the calcium balance, the PTH levels in smokers are of interest. SUBJECTS AND METHODS: In the fifth Tromsø study, smoking status was recorded and serum PTH measured in 7896 subjects. Intakes of calcium and vitamin D were evaluated with a food-frequency questionnaire. In a follow-up study on 205 subjects, serum 25-hydroxyvitamin D, calcium absorption, and renal excretion of calcium were measured in addition. RESULTS: The serum PTH levels were significantly lower in smokers than non-smokers (3.1+/-1.4 vs 3.6+/-1.9 pmol/l in males; 3.1+/-1.5 vs 3.6+/-1.8 pmol/l in females (P < 0.001) after correcting for confounding variables, linear regression). In the smokers, there was no association between number of cigarettes smoked and serum PTH. One year after quitting smoking, serum PTH levels were similar to those of people who had never smoked. The smokers had significantly lower intake of vitamin D, lower serum levels of 25-hydroxyvitamin D and lower calcium absorption. The intake of calcium and the renal excretion of calcium were similar to that in non-smokers. CONCLUSIONS: Smokers have lower serum PTH levels than non-smokers. This cannot be explained by the predictors of serum PTH measured in our study.

Anti-dsDNA antibodies and disease classification in antinuclear antibody positive patients: the role of analytical diversity.

BACKGROUND: The presence of "anti-DNA antibodies in abnormal titres" is a well established criterion for SLE classification, but there is no agreement on the performance of this test. OBJECTIVE: To study the correlation between clinical findings and five different solid and solution phase anti-DNA antibody assays. METHODS: 158 consecutively collected ANA positive sera were studied in a double blind fashion. Anti-DNA antibodies were determined by different solid phase assays (ssDNA-, dsDNA- specific ELISA, EliA anti-dsDNA assay, Crithidia luciliae assay), and by an experimental solution phase anti-DNA assay using biotinylated pUC18 plasmid, human, calf thymus, and E coli DNA. Antibody affinity was determined by surface plasmon resonance. Clinical data were obtained independently of the laboratory analyses and later related to the anti-dsDNA findings. RESULTS: Anti-dsDNA antibodies were most frequently detected by ELISA, but were not specific for SLE as they were present in up to 30% of other disease groups. Those detected by the Crithidia luciliae assay were predictive for SLE, while antibodies binding in solution phase ELISA using the pUC18 correlated strongly with the Crithidia luciliae assay. Surface plasmon resonance analysis showed that antibody binding to pUC18 was not due to higher relative affinity for dsDNA in general, but apparently to specificity for that plasmid DNA. Serum samples from three patients with lupus nephritis were positive in both pUC18 solution phase and Crithidia luciliae assays. CONCLUSIONS: Assay principle selection is decisive for the detection of clinically significant anti-DNA antibodies. Revision of the anti-DNA antibody criterion in the SLE classification may be needed.

Tumor necrosis factor-related apoptosis-inducing ligand induces apoptosis in human articular chondrocytes in vitro.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is produced by immune cells and by mediating apoptosis, TRAIL plays an important role in tumor surveillance. TRAIL binds four different membrane-bound receptors: DR4, DR5, DcR1, and DcR2. The DR4- and DR5-receptors mediate apoptosis, whereas the others do not. We demonstrated by reverse transcriptase-polymerase chain reaction and flow cytometry that, in vitro, normal human articular chondrocytes express the receptors mediating apoptosis (DR4 and DR5) and one of the decoy receptors (DcR2). Also, we demonstrated that chondrocytes were subjected to cell death within few hours after challenge with TRAIL and that cytotoxicity was dose-dependent. Treated cells had apoptotic morphology accompanied by active caspase-3 immunoreactivity. These data indicate that normal human articular chondrocytes are susceptible to TRAIL-mediated apoptosis, which otherwise is typical for transformed cells, and also that death receptors and their respective ligands may have a crucial role in cartilage generation and destruction.

Human articular chondrocytes express functional leptin receptors.

The effects of leptin hormone are mediated by interactions with several physiological regulatory systems and the cytokine network, and by targeting cells directly. The leptin receptor is a member of the class I cytokine receptor family, and its signal transduction resembles that induced by many cytokines. We demonstrated that serially cultured human articular chondrocytes possess the leptin receptor (Ob-R), and that this receptor was present on chondrocytes in native human cartilage. In cultured chondrocytes we detected mRNA for the functional isoform of leptin receptor (Ob-Rb or Ob-R(L)), and it was revealed that ligand binding resulted in phosphorylation of signal transducers and activators of transcription, namely STAT1 and STAT5. Chondrocytes stimulated with leptin exhibited an increased proliferation and an enhanced synthesis of extracellular matrix (proteoglycans and collagen). These results indicate that leptin affects cartilage generation directly, which is a novel role for leptin in skeletal growth and development.

Enzymatic treatment of spermatozoa with a trypsin solution, SpermSolute: improved motility and enhanced ATP concentration.

We have developed a solution, fully described in this report, that can be used in a pretreatment procedure to promote liquefaction and to enhance motility during preparation of spermatozoa. It was applied to native ejaculates prior to swim-up and, in parallel investigations, motility and adenosine triphosphate concentration were compared in treated and untreated samples, which revealed that the solution significantly improved both parameters. The solution, named SpermSolute, is based on a proteinase (trypsin), which previously has been shown to stimulate the activity of a glycolytic key-enzyme. We speculate that our findings reflect intracellular enzyme activation and we suggest that our formula can be used in sperm preparation to prevent cell aggregates and to promote liquefaction, in addition to promotion of motility.

Improvement of a cytokine (TNF-α) bioassay by serum-free target cell (WEHI 164) cultivation.

The elaboration of a sensitive bioassay for assessment of tumour necrosis factor alpha (TNF-α) in a defined medium is described. The assay is based on the cytotoxic effect of TNF-α on a target cell line, the murine fibrosarcoma WEHI 164 clone 13. Cytotoxicity was assessed by detecting the rate of tetrazolium salt reduction employing a spectrophotometer (ELISA-reader). A similar bioassay was used previously to assess TNF-α, though this was dependent on cell growth in a medium containing serum. By employing a synthetic serum replacement, the WEHI cells were adapted to growth in a defined medium which allowed both the propagation of the cell line and the assay to be performed under completely defined conditions. Thus, factors in serum that may influence the TNF-α assessment, such as growth factors, cytokines, soluble cytokine-receptors and macroglobulin, were avoided. The only protein required in this bioassay was insulin, while albumin was added as a carrier protein and to protect the cytokine against loss of biological activity during multiple freeze and thaw cycles. The present assay was optimised to achieve a high sensitivity and, by testing endogenous TNF-α originating from the macrophage-like cell line RAW in both the serum-free and serum-based assay, we found the highest sensitivity in the assay based on defined medium. The LC50 of recombinant mouse and human TNF-α were in the serum-free and serum-based assays considered to be 25 and 50 pg mL-1, respectively. The demonstration of a culture condition that enables long-term cultivation of target cells and a bioassay in a completely defined medium is in our opinion a substantial contribution to more reliable cytokine assessment.

A sensitive serum-free colorimetric assay for the detection of cytotoxic effects of pesticides.

A new method of cell quantification in the Hybritest bioassay is described. This test is based on culturing the hybridoma cell line 1E6 in the serum-free medium RPMI-SR3 and determination of cytotoxicity by growth inhibition. By employing a tetrazolium salt (MTT), the cell number were quantified colorimetrically using an ELISA reader. This assay carried out in microtiter plates saved time, labour and expenses. It was demonstrated that the sensitivity of 1E6 to pesticide toxicity (glyphosate and cypermethrine) was considerably higher in serum-free medium than in serum-containing medium. Furthermore, it is suggested that this assay may represent an alternative to the use of living animals in toxicological experiments.

A new sensitive cell culture test for the assessment of pesticide toxicity.

A new, simple and sensitive cell culture test for the determination of cytotoxicity of pesticides is described. This test is based on assessment of the growth inhibitory effect of pesticides on the rapidly growing mouse hybridoma cell line 1E6 cultivated in a defined serum-free medium (RPMI-SR3). In addition the cytotoxicity in serum-containing medium was investigated. The results showed that the sensitivity of 1E6 cell towards the toxicity of the pesticides; carbofuran, cypermethrin, lindane, glyphosate and 2,4-D was considerably higher in the serum-free medium than in serum-containing medium. Also IC50 values of these pesticides were compared with LD50 values obtained from the literature. The ratio between the in vitro IC50 and the in vivo LD50 showed that the present cell culture test determine the toxicity of low levels of pesticides with much higher sensitivity than tests based on using animals.