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Biomedical subjects

L Hellström

Publications and source records attributed to L Hellström.

At least 19 recordsLinked to original sources

Integration of lucid individuals and agitated individuals with dementia in different care units.

The purpose of this study was to illuminate how the integration of lucid individuals and agitated cognitively impaired individuals affects aspects of perceived quality of care. A questionnaire was mailed to hospital wards, nursing home wards and residential homes in Sweden. Nursing staff replied to the questionnaire on behalf of each care unit. Integration of cognitively impaired and lucid patients/residents was identified as a problem, regardless of whether the care unit was a hospital ward, nursing home or residential home. Agitated behaviours in people who were cognitively impaired could result in lucid residents becoming anxious, afraid and irritated. This in turn could lead to an exacerbation of behaviour in residents who were already agitated. Sometimes a lucid patient/resident was required to share a room with an agitated individual. There is a need for staff training specific to the needs of people with dementia. Findings suggest that there is a shortage of units designed specifically for the care of agitated cognitively impaired patients/residents. The findings of this study support the need for healthcare providers in long-term care settings to maintain the rights and well being of all patients/residents.

Adult↗

Cadmium exposure and end-stage renal disease.

Environmental exposure to cadmium may cause kidney damage and tubular proteinuria. We investigated the relationship between low-level cadmium exposure and end-stage renal disease (ESRD), indicated by renal replacement therapy (RRT), in a Swedish population environmentally or occupationally exposed to cadmium. Based on records of all persons in the population previously or presently employed in cadmium-battery production or residing in cadmium-polluted areas near the battery plants, we defined exposure as high (occupational), moderate (domicile < 2 km from a plant), low (domicile 2 to 10 km from a plant), or no exposure (domicile > 10 km from a plant). Comprehensive data were available for all individuals undergoing RRT since 1978. The annual incidence of RRT increased from 41 per million in the age group 20 to 29 years to 243 per million in the age group 70 to 79 years and was greater in a priori-defined populations with cadmium exposure. Adjusting for age and sex gave an increased Mantel-Haenszel rate ratio (MH-RR) of 1.8 (95% confidence interval [CI], 1.3 to 2.3) for RRT in the cadmium-exposed population compared with the unexposed group; the MH-RR was even higher for women (MH-RR, 2.3; 95% CI, 1.5 to 3.5). Directly age-standardized rate ratios for RRT and cadmium exposure increased from 1.4 (95% CI, 0.8 to 2.0) in the low-exposure group to 1.9 (95% CI, 1.3 to 2.5) and 2.3 (95% CI, 0.6 to 6.0) in the moderate- and high-exposure groups, respectively. We conclude that exposure to occupational or relatively low environmental levels of cadmium appears to be a determinant for the development of ESRD.

Adolescent↗

Imported rocket salad partly responsible for increased incidence of hepatitis A cases in Sweden, 2000-2001.

An increased incidence of domestic hepatitis A without any obvious source of infection in Sweden and a small outbreak in late spring 2001 led to the undertaking of a case-control study. Consumption of imported rocket salad was clearly associated with disease (odds ratio 9.1, 95% confidence interval 1.5 to 69). The importation of vegetables from countries where hepatitis A is endemic to countries where this disease is not endemic continues to be a public health problem.

Adolescent↗

Excessive fat accumulation is associated with the TNF alpha-308 G/A promoter polymorphism in women but not in men.

AIMS/HYPOTHESIS: Tumour necrosis factor alpha (TNF alpha) is a candidate gene for the development of obesity, which in turn is a major risk factor for diabetes mellitus. The aim of our study was to investigate whether a previously known NcoI-sensitive polymorphism (-308 G/A) in the promoter region of the TNF alpha gene was related to body weight. METHODS: Genotyping was done in 239 male and 342 female non-diabetic subjects with a marked variation in body mass index (BMI). RESULTS: We found three genotypes; AA (n = 13), AG (n = 158) and GG (n = 410). When the material was divided according to sex, allele specific phenotypic differences were confined to women. The female subjects carrying the AA genotype were markedly more obese than both the AG and GG carriers (mean BMI = 41.4 vs 32.3 and 31.7 kg/m2, respectively, p = 0.02). The body fat content of female AA carriers was increased by one-third compared with AG/GG carriers (p = 0.02). We found no differences between genotypes with respect to waist-to-hip ratio, blood pressure or metabolic variables. Among obese female subjects (BMI > 27 kg/m2), we also found that the BMI and body fat content of AA carriers (n = 7) were also higher than for AG/GG carriers. CONCLUSION/INTERPRETATION: The AA-variant at position -308 in the promoter region of the TNF alpha gene could be an important genetic factor behind excessive fat accumulation in women.

Adipose Tissue↗

Influence of heredity for obesity on adipocyte lipolysis in lean and obese subjects.

OBJECTIVE: To evaluate a possible influence of a hereditary trait for obesity on the regulation of adipocyte metabolism in vitro in subcutaneous fat cells in obese and non-obese subjects. DESIGN: A biopsy from abdominal subcutaneous fat was obtained from consecutive subjects with or without a family trait for obesity. A positive family history of obesity was considered present if one or more of the first degree relatives had a BMI of 27 kg/m2 or more. SUBJECTS: 67 non-obese and 60 obese subjects, age 19-60 y. A family trait for overweight was present in 42 of the lean subjects and in 50 of the obese subjects. MEASUREMENTS: Fat cells were isolated and incubated in vitro with isoprenaline (a non-selective beta-adrenoceptor agonist), forskolin (activates the adenylyl cyclase) and dibutyryl cyclic AMP (stimulates the protein kinase hormone-sensitive lipase complex). Glycerol release was measured and used as lipolytic index. RESULTS: Maximal lipolytic response per g triglycerides was about 50% lower in obese subjects both with and without a positive heredity and in non-obese subjects with a family trait for obesity as compared to non-obese subjects without such trait (P=0.0001). Fat cell volume was twice as high in obese as compared to lean subjects. Drug-induced maximal glycerol release per fat cell in the obese subjects, regardless of family history of obesity, reached a similar level, but did not exceed that of the lean group without heredity. CONCLUSIONS: Obesity is associated with catecholamine resistance with a relatively ineffective lipolysis in fat cells, and presence of a family history of obesity was not associated with a further suppression of lipolysis. In the lean subjects, heredity for obesity significantly influenced lipolysis to similar low levels as in the obese subjects.

Adipocytes↗

Mechanisms behind gender differences in circulating leptin levels.

OBJECTIVES: To investigate gender differences in circulating leptin levels and adipose tissue production of leptin. DESIGN SETTING AND SUBJECTS: Thirty-two men and 63 women with a large interindividual variation in body mass index (BMI), but otherwise healthy, were investigated after an overnight fast. Body fat (bioimpedance), abdominal subcutaneous adipose tissue secretion of leptin in vitro and serum leptin were determined. RESULTS: Although there was no gender difference in mean BMI or fat cell size, mean percentage body fat was 49 in women and 36 in men (P < 0.001). At each level of BMI, serum leptin levels were about two times higher in women than in men (P < 0.001). Adipose tissue secretion rate of leptin in men was two-thirds of that in women (P < 0.05). The gender differences in body fat content, serum leptin and leptin secretion were observed in obese (BMI > 27 kg m-2) as well as non-obese subjects. Serum leptin levels (P < 0.001) and leptin secretion rate (P < 0.01) correlated positively with body fat content in either sex. However, the gender differences in serum leptin (P < 0.001) and leptin secretion rate (P < 0.01) remained statistically significantly different even when the values were adjusted for body fat. CONCLUSION: The gender difference in circulating leptin concentrations can be due to at least two different mechanisms. A higher proportion of adipose tissue and increased production rate of leptin per unit mass of adipose tissue might explain why women have higher circulating leptin levels than men.

Adipose Tissue↗

Low level exposure to cadmium and early kidney damage: the OSCAR study.

OBJECTIVES: To study the dose-response relation between cadmium dose and renal tubular damage in a population of workers and people environmentally or occupationally exposed to low concentrations of cadmium. METHODS: Early kidney damage in 1021 people, occupationally or environmentally exposed to cadmium, was assessed from cadmium in urine to estimate dose, and protein HC (alpha(1)-microglobulin) in urine to assess tubular proteinuria. RESULTS: There was an age and sex adjusted correlation between cadmium in urine and urinary protein HC. The prevalence of tubular proteinuria ranged from 5% among unexposed people to 50% in the most exposed group. The corresponding prevalence odds ratio was 6.0 (95% confidence interval (95% CI) 1.6 to 22) for the highest exposure group, adjusted for age and sex. Multiple logistic regression analysis showed an increasing prevalence of tubular proteinuria with urinary cadmium as well as with age. After adjustment to the mean age of the study population (53 years), the results show an increased prevalence of 10% tubular proteinuria (taking into account a background prevalence of 5%) at a urinary cadmium concentration of 1.0 nmol/mmol creatinine. CONCLUSION: Renal tubular damage due to exposure to cadmium develops at lower levels of cadmium body burden than previously anticipated.

Adult↗

Low-level cadmium exposure and osteoporosis.

Osteoporosis is a major cause of morbidity worldwide. A number of risk factors, such as age and gender, are well established. High cadmium exposure causes renal damage and in severe cases also causes osteoporosis and osteomalacia. We have examined whether long-term low-level cadmium exposure increases the risk of osteoporosis. Bone mineral density (BMD) in the forearm was measured in 520 men and 544 women, aged 16-81 years, environmentally or occupationally exposed to cadmium, using dual-energy X-ray absorptiometry (DXA) technique. Cadmium in urine was used as the dose estimate and protein HC was used as a marker of renal tubular damage. There was a clear dose-response relation between cadmium dose and the prevalence of tubular proteinuria. Inverse relations were found between cadmium dose, tubular proteinuria, and BMD, particularly apparent in persons over 60 years of age. There was a dose-response relation between cadmium dose and osteoporosis. The odds ratios (ORs) for men were 2.2 (95% CI, 1.0-4.8) in the dose group 0.5-3 nmol Cd/mmol creatinine and 5.3 (2.0-14) in the highest dose category (> or = 3 nmol/mmol creatinine) compared with the lowest dose group (< 0.5 nmol Cd/mmol creatinine). For women, the OR was 1.8 (0.65-5.3) in the dose group 0.5-3 nmol Cd/mmol creatinine. We conclude that exposure to low levels of cadmium is associated with an increased risk of osteoporosis.

Absorptiometry, Photon↗

The different effects of a Gln27Glu beta 2-adrenoceptor gene polymorphism on obesity in males and in females.

OBJECTIVES: To investigate the role of a polymorphism in codon 27 (Gln27Glu) of the beta 2-adrenoceptor gene for obesity in males compared to previously investigated females with an association of this polymorphism to obesity. DESIGN: Population-based study. SETTING: Medical department at a University Hospital. SUBJECTS: A total of 138 non-related Swedish males with body mass indexes (BMI) in the range 19.4-53.4 kg m-2 were recruited as: healthy volunteers, healthy obese subjects and subjects undergoing surgery for uncomplicated gallstone or abdominal hernia. In order to investigate the impact of gender, the results were compared with a subset of an earlier investigated female population of 109 Swedish females. Obesity was defined as a BMI > 27 kg m-2. MAIN OUTCOME MEASURES: Genotype examination of beta 2-adrenoceptor polymorphism in codon 27 with polymerase chain reaction and restriction fragment length polymorphism. RESULTS: The allele frequency of Gln27 and Glu27 did not differ between males and females when obese and non-obese subjects were investigated together. However, in obese males, the frequency of the Glu27 allele was significantly decreased (P = 0.034), whereas the frequency of this allele was increased in obese females (P = 0.013). No impact of the female androgen status on the distribution of the Gln27Glu polymorphism could be demonstrated in the obese females. CONCLUSION: A positive association between obesity and the Glu27 genetic variant in the beta 2-adrenoceptor exists in females, whereas in males there is a negative correlation between Glu27 and obesity. The findings suggest that different genetic factors contribute to obesity in males and females.

Adult↗

Total fibronectin in maternal plasma as a predictor for preeclampsia.

OBJECTIVE: To assess the ability of measuring total maternal plasma fibronectin in predicting the risk of developing preeclampsia. METHOD: In a cohort of 657 initially normotensive pregnant nulliparous women blood samples were collected at 26, 30 and 34 weeks of gestation. After delivery 3 groups were selected for measurement of total plasma fibronectin. The first group comprised 24 women who developed preeclampsia; the second 21 women who developed gestational hypertension, and the third 89 age-matched controls who remained normotensive. RESULTS: In women who developed preeclampsia the fibronectin levels were higher at 26 (p < 0.01), 30 (p < 0.001) and 34 weeks of gestation (p < 0.001) than in pregnant controls. In the general population of pregnant nulliparous women the estimated risk of subsequent preeclampsia correlated with the fibronectin level at each measurement. In women with fibronectin levels within the 25th percentile at the 26th week of gestation, the risk was </=1.9% and within the 90th percentile >/=6.2%. The change in fibronectin levels between 26 and 34 weeks of gestation was the only variable that remained statistically associated with preeclampsia (p = 0.0002) in multivariate analysis. In this model the risk figures for the corresponding percentiles were </=1.0 and >/=5.8%, respectively. CONCLUSION: Longitudinal assessment of the change in total fibronectin levels predicted preeclampsia slightly better than cross-sectional analysis of fibronectin at any gestational age. Nevertheless, measurement of total fibronectin in maternal plasma could not be proven to be a useful clinical predictor for preeclampsia in a general obstetric population of nulliparous women.

Adult↗

Lipolytic response during spontaneous hypoglycaemia in insulin-dependent diabetic subjects.

The adipose tissue lipolytic response to spontaneous, non-experimental hypoglycaemic episodes was investigated in patients with IDDM during ordinary life conditions. The absolute concentration of glucose and glycerol in subcutaneous adipose tissue was monitored in mobile patients with microdialysis in 16 IDDM subjects. The absolute glycerol level in adipose tissue was about five times as high as in venous plasma, whereas the glucose concentration was almost the same in the two compartments. Fourteen hypoglycaemic episodes (glucose < 3.5 mmol/l) were recorded. Adipose tissue glycerol increased markedly by 75 % in response to hypoglycaemia and remained increased during at least 4 hours following glucose nadir (F = 3.70, p = 0.003). The circulating levels of free fatty acids increased about three-fold in parallel to the in situ lipolytic response (F = 2.98, p = 0.025). The same lipolytic response was observed whether or not the hypoglycaemic event was perceived by the patient. A rapid decrease in glucose concentration above hypoglycaemic levels did not affect the adipose tissue dialysate glycerol. It is concluded that spontaneous hypoglycaemia elicits a long-term lipolytic response in adipose tissue as evidenced by increased levels of glycerol in adipose tissue with a parallel increase in serum free fatty acids. However, lipolysis is not activated by a rapid glucose decrease per se. The microdialysis method can be used to characterise the lipolytic response to hypoglycaemic episodes in every day life of IDDM patients.

Adipose Tissue↗

Human beta-2 adrenoceptor gene polymorphisms are highly frequent in obesity and associate with altered adipocyte beta-2 adrenoceptor function.

Catecholamines play a central role in the regulation of energy expenditure, in part by stimulating lipid mobilization through lipolysis in fat cells. The beta-2 adrenoceptor (BAR-2) is a major lipolytic receptor in human fat cells. To determine whether known polymorphisms in codons 16, 27, and 164 of this receptor play a role in obesity and subcutaneous adipocyte BAR-2 lipolytic function, we investigated a group of 140 women with a large variation in body fat mass. Only the polymorphisms in codons 16 and 27 were common in the study population. The Gln27Glu polymorphism was markedly associated with obesity with a relative risk for obesity of approximately 7 and an odds ratio of approximately 10. Homozygotes for Glu27 had an average fat mass excess of 20 kg and approximately 50% larger fat cells than controls. However, no significant association with changes in BAR-2 function was observed. The Arg16Gly polymorphism was associated with altered BAR-2 function with Gly16 carriers showing a fivefold increased agonist sensitivity and without any change in BAR-2 expression. However, it was not significantly linked with obesity. These findings suggest that genetic variability in the human BAR-2 gene could be of major importance for obesity, energy expenditure, and lipolytic BAR-2 function in adipose tissue, at least in women.

Adipocytes↗

Followup after 11 years--update of mortality results in the Stockholm mammographic screening trial.

Results from several randomised mammography screening trials have shown that it is possible to reduce mortality in breast cancer by mammographic screening at least for women above 50 years of age. The purpose of this article is to present data on mortality in breast cancer in study and control groups of the Stockholm trial after 11 years of followup, to analyse which age group benefits most from screening. In March 1981, 40,318 women in Stockholm, aged 40 through 64 years, entered a randomized trial of breast cancer screening by single view mammography alone, versus no intervention in a control group of 20,000 women. Two screening rounds were performed and the attendance rate was over 80% in the two rounds. During 1986 the control group was invited once to screening. Totally 428 and 217 cases of breast cancer were diagnosed in the study and control groups respectively. After a mean follow-up of 11.4 years a nonsignificant mortality reduction of 26% was observed for the whole study group, with a relative risk (RR) of death in breast cancer of 0.74 (CI(confidence interval) = 0.5-1.1). For women aged 50-64 years a significant 38% mortality reduction was observed with a RR of 0.62 (CI = 0.38-1.0). For women aged 40-49 years no effect on mortality was found, with a RR of death in breast cancer of 1.08 (CI = 0.54-2.17). The breakpoint for benefit in this study seemed to be at 50 years of age when 5-year age groups were analysed, but this tendency is uncertain because of the low statistical power in the analysis of the younger age groups. Long screening intervals, the use of single-view mammography, and the fact that more than 50% of the women in age group 40-49 years were still below 50 years of age when the study was closed, were all facts that could have influenced the results in age group 40-49 years. Larger studies are needed to answer the question whether mammographic screening can be successful in younger age groups.

Adult↗

Lipolytic catecholamine resistance linked to alpha 2-adrenoceptor sensitivity--a metabolic predictor of weight loss in obese subjects.

OBJECTIVE: The weight loss achieved during treatment with very-low-calorie diets (VLCD) varies between individuals. The aim of this study was to investigate whether interindividual variations in catecholamine-induced lipolysis are of importance for the rate of weight loss during VLCD. DESIGN: Prospective study. SUBJECTS: Twenty-eight obese, but otherwise healthy and drug-free women aged 20-57 y with BMI 33.3-47.5 kg/m2 were investigated before entering a four week weight reduction program with a calorie-restricted diet. MEASUREMENTS: A subcutaneous adipose tissue biopsy was obtained from the abdominal area. Isolated fat cells were prepared and incubated in vitro with agents acting on lipolysis at defined steps in the lipolytic cascade. Glycerol release was measured and used as a lipolytic index. Following the biopsy, the subjects underwent a four week VLCD treatment. RESULTS: The decrease in body weight in the whole group ranged between 4.8 and 13.5 kg. Dietary compliance was ascertained by daily measurements of urine-ketones and regular interviews and was satisfactory in all subjects throughout the study. Based on percent body weight reduction, the material was divided into two equally sized groups, classified as rapid or slow weight losers. The rapid weight losers were 10-fold more sensitive to the lipolytic effect of noradrenaline (P = 0.04) and 10-fold less sensitive (P = 0.002) to the antilipolytic effect induced by the alpha 2-adrenoceptor agonist clonidine than the slow weight losers. In the whole material, weight loss was significantly correlated (adjusted r2 = 0.25) with alpha 2-adrenoceptor sensitivity. CONCLUSION: Rapid weight loss during VLCD is associated with increased adipocyte lipolytic sensitivity to catecholamines due to decreased alpha 2-adrenoceptor sensitivity, which in turn may promote lipid mobilization. It appears that variations in alpha 2-adrenoceptor sensitivity in adipocytes may be predictive of weight loss during VLCD.

Adenosine Deaminase↗

Catecholamine-induced adipocyte lipolysis in human hyperthyroidism.

Increased lipid mobilization in thyrotoxicosis is attributed to amplification of catecholamine action in fat cells by thyroid hormones. We investigated the adrenergic regulation of lipolysis in isolated sc abdominal fat cells obtained from 14 patients with thyrotoxicosis and 18 control subjects. Ten of the hyperthyroid subjects were also reinvestigated after antithyroid treatment. The thyrotoxic state was associated with a 3-fold increase in maximum norepinephrine-induced lipolysis (P < 0.005), unaltered sensitivity to dobutamine (selective beta 1-adrenoceptor agonist) and clonidine (selective alpha 2-adrenoceptor agonist), but 15 times enhanced sensitivity to terbutaline (selective beta 2-adrenoceptor agonist; P < 0.01). Moreover, thyrotoxicosis was accompanied by a 3-fold increase in beta 2-adrenoceptor number (P < 0.005), but unchanged beta 1-adrenoceptor levels. Further, the lipolytic effects of dibutyryl cAMP (activating protein kinase A and thereby hormone-sensitive lipase) and forskolin (activating adenylate cyclase) were about 60% enhanced (P < 0.005). No change in the maximum activity of the hormone-sensitive lipase could be demonstrated in the hyperthyroid state compared to that in the euthyroid state. The observed abnormalities in lipolysis and beta 2-adrenoceptor number were normalized after antithyroid treatment. It is concluded that in human hyperthyroidism, the interactions between thyroid hormone and catecholamines in adipocytes involve abnormalities at both receptor and postreceptor levels. The former mechanism seems to be a selective increase in the expression of the beta 2-adrenoceptors. The latter mechanism involves increased ability of cAMP to activate hormone-sensitive lipase, but not a change in maximum enzyme capacity.

Adipocytes↗

Adipocyte lipolysis in normal weight subjects with obesity among first-degree relatives.

In this study we investigated whether fat cell lipolysis could be involved in the aetiology of obesity by comparing non-obese subjects with (Hob) or without (Hnorm) a family trait for overweight. A family history of obesity was present when at least one of the first-degree relatives had body mass index of 27 kg/m2 or more. Twenty-seven healthy, drug-free non-obese adult subjects were investigated; 13 were Hob and the remaining 14 were Hnorm. Eleven Hob had at least one obese parent. Isolated fat cells from abdominal subcutaneous adipose tissue were incubated in vitro. Glycerol release (lipolysis index), mRNA levels and enzymatic activity of hormone-sensitive lipase and radioligand binding to beta 1- and beta 2-adrenoceptors were determined. The lipolytic effects of noradrenaline (major endogenous lipolytic agent), isoprenaline (a non-selective beta-adrenoceptor agonist), forskolin (a direct activator of adenylyl cyclase) and dibutyryl cyclic AMP (activating protein kinase and thereby hormone-sensitive lipase) were reduced by about 50% (p from 0.001 to 0.01). The maximum activity of hormone-sensitive lipase was reduced 50% in Hob (p < 0.05) and correlated with the lipolytic responsiveness of fat cells in the whole population (r = 0.71). However, there was no difference between the groups in steady-state mRNA levels for the enzyme. Beta 1-->, beta 2- and alpha 2-adrenoceptor sensitivity as well as beta 1- and beta 2-adrenoceptor numbers were normal in Hob. Fasting plasma insulin was 49.1 and 32.6 pmol/l, respectively in Hob and Hnorm (p = 0.01). There was, however, no significant correlation between lipolysis in vitro and plasma insulin. Thus, lipolytic catecholamine resistance in fat cells, at least partly due to impaired function of hormone-sensitive lipase, is an adipocyte abnormality associated with a family tendency to obesity.

Adipocytes↗

Urinary incontinence: a minor risk factor for hip fractures in elderly women.

OBJECTIVE: The aim of the study was to study the influence of urinary disorders as urinary incontinence on the prevalence of hip fracture in 85-year-old women. METHODS: A representative community-based population study was performed at the geriatric outpatient department of a university hospital in a sample consisting of 658 85-year-old women, of which 69% were living at home and 31% were living were living in institutions. The prevalence of hip fractures was registered and measurement with dual photon absorptiometry of the right calcaneum was performed. The subjects were questioned covering sociodemographic background, the occurrence, type, frequency and amount of urinary incontinence, medical examinations and investigations of the prevalence of hip fracture. RESULTS: Hip fracture was significantly associated with urinary incontinence (P < 0.001) for women and the odds ratio of hip fracture was twice that found in general population (OR = 2.42). Body mass index and weight were both significant higher (P < 0.01) among women with urinary incontinence and hip fracture. The frequency of urinary incontinence was also significant correlated to hip fracture (P < 0.001). Subjects with diabetes had a tendency to be associated with urinary incontinence (P < 0.06). In a logistic multiple regression analysis, body mass index, urinary incontinence and cancers were the only explanatory factors for hip fractures at 85 years of age. CONCLUSION: The association between postmenopausal urinary incontinence and hip fractures are multifactorial and whether this is a result of decreasing estrogen levels or a result of general aging process is still under debate. Women with urinary incontinence and earlier atrumatic multiple postmenopausal fractures should be considered a special target group for estrogen prophylaxis in order to prevent further severe fractures.

Aged↗

Gender differences in adrenergic regulation of lipid mobilization during exercise.

Gender differences in adrenergic regulation of glycerol levels in subcutaneous, abdominal adipose tissue were investigated during submaximal exercise in non-obese, healthy men and women, using microdialysis. During exercise, glycerol levels in venous plasma and venous serum concentrations of free fatty acids increased more in women and reached about two-fold higher values than in men (p < 0.005 or less). Plasma noradrenaline and insulin did not differ between the sexes, whereas plasma adrenaline was two-fold higher in men than in women during exercise (p < 0.01). The glycerol levels in adipose tissue increased during exercise and decreased in the post-exercise period in either sex. When the non-selective beta adrenoceptor blocking agent propranolol was added to the microdialysis perfusate before exercise was initiated, the subsequent increase in dialysate glycerol was significantly diminished in both sexes (p < 0.05). A similar addition of the alpha adrenoceptor blocking agent phentolamine, however, caused a significant further rise in tissue glycerol in men (p < 0.05), whereas the exercise induced increase in glycerol levels remained unaffected by phentolamine in women. Adipose tissue blood flow did not change during exercise in either men or women. In either sex, dialysate lactate levels increased during exercise. This increase was not altered if alpha- or beta-blocking agents were added to the perfusate. In summary, during short term submaximal work, women have a higher increase in circulating lipid than men. This appears, at least in part, to be due to a sex difference in the adrenergic regulation of lipid mobilization during exercise. In men exercise activates beta- as well as alpha-adrenergic receptors in adipose tissue, whereas only beta receptors are activated in adipose tissue of women. Finally, methodological investigations indicate that microdialysis is a valid method for short-term exercise experiments.

Adipose Tissue↗