PubMed Health⌕ Search

Biomedical subjects

P Mårin

Publications and source records attributed to P Mårin.

At least 19 recordsLinked to original sources
PubMed2001

No effect of the cortisol-synthesis inhibitor metyrapone on alcohol drinking: a pilot study.

Two bases for this study were the theory of stress as a provoking factor for high alcohol consumption in human being and findings that the stress hormones stimulate ethanol intake in rats. We therefore investigated whether the cortisol-synthesis inhibitor metyrapone could reduce high alcohol consumption in socially stable subjects who reported drinking mainly for relaxation purposes. Most of the investigated subjects were found to be alcohol dependent (81%), with moderately high levels of intake, yet they had not reported more severe life problems. All subjects reported their daily alcohol consumption during 2-week baseline, medication, and postmedication periods. Sixteen subjects were given 1 g of metyrapone orally daily for 14 days, and 15 subjects received placebo. Morning serum cortisol concentration was assessed four times in the course of the study period. Metyrapone treatment was not found to reduce alcohol consumption more than placebo. Serum cortisol concentrations remained within the laboratory reference interval during the study and did not differ between the study groups. In this study, we found that a cortisol-synthesis inhibitor had no effect on alcohol consumption. One reason may be that cortisol secretion has no role in the maintenance of high alcohol consumption. On the other hand, because this study is the first of its kind, further studies using other doses of treatment and treatment schedules are suggested.

Adult↗
PubMed1998

Serum leptin concentration and insulin sensitivity in men with abdominal obesity.

OBJECTIVE: We have examined the association between generalized adiposity, abdominal adiposity, insulin sensitivity, and serum levels of leptin in a cross-sectional study of abdominally obese men. RESEARCH METHODS AND PROCEDURES: Thirty men, 48 to 66 years of age with a body mass index (BMI) of between 25 kg/m2 and 35 kg/m2 and a waist hip ratio of >0.95, were included in the study. Serum leptin concentration was measured using radioimmunoassay. Total body fat percentage was determined from total body potassium, abdominal adiposity was measured by computed tomography, and the glucose disposal rate (GDR) was measured during an euglycemic, hyperinsulinemic glucose clamp. RESULTS: Significant correlations were found between serum leptin concentration and BMI, percentage body fat, abdominal subcutaneous adipose tissue, serum insulin, GDR, and 24-hour urinary-free cortisol. In a multiple regression analysis, it was shown that abdominal subcutaneous adipose tissue, GDR, and BMI explained 72% of the variability of serum leptin concentration. GDR demonstrated an independent inverse correlation with serum leptin concentration. DISCUSSION: In abdominally obese men with insulin resistance, it was demonstrated that most of the individual variability in serum leptin concentration was explained by the amount of subcutaneous abdominal adipose tissue, insulin sensitivity, and BMI.

Abdomen↗
PubMed1998

Androgens and abdominal obesity.

Central or visceral obesity is recognized as a main risk factor for cardiovascular disease and type 2 diabetes mellitus. The co-existence of visceral obesity, increased blood lipid levels, hypertension and impaired glucose tolerance defines the metabolic syndrome that today is widely recognized as one of the prime factors behind cardiovascular morbidity and mortality. Endocrine disorders such as insulinoma, hypothyroidism and hypercortisolism are known to cause obesity. However, it is only hypercortisolism that is associated with increased abdominal fat accumulation. Recently, new findings have shed light on subtle endocrinopathies that are prevalent in individuals presenting with the metabolic syndrome. Such derangements are of borderline character and often fall within the normal reference range. Intervention studies demonstrate that correction of relative hypogonadism in men with visceral obesity and other manifestations of the metabolic syndrome seem to decrease the abdominal fat mass and reverse the glucose intolerance, as well as lipoprotein abnormalities in the serum. Further analysis of the underlying mechanism has also disclosed a regulatory role for testosterone in counteracting visceral fat accumulation. Longitudinal epidemiological data demonstrates that relatively low testosterone levels are a risk factor for development of visceral obesity. The primary event that triggers the initial development of visceral obesity is not known, but it seems plausible that increased activity in the hypothalamus-pituitary-adrenal axis can be of major importance.

Abdomen↗
PubMed1998

Effects of growth hormone treatment on the leptin system and on energy expenditure in abdominally obese men.

The present study has examined the short- and long-term effects of growth hormone (GH) treatment on the leptin system and energy expenditure. Thirty male individuals with abdominal obesity were randomised to GH or placebo treatment in a 9-month, double-blind study. The dose of GH was 9.5 microg/kg, administered subcutaneously every evening. Serum leptin concentrations were measured by a human leptin RIA. Total RNA was isolated from adipose tissue biopsies and leptin mRNA levels were determined by a semi-quantitative reverse transcriptase-PCR assay. Body composition was determined by potassium-40 and the basal metabolic rate (BMR) was measured by a computerised, ventilated, open-hood system. As compared with placebo, an overall decrease in serum leptin concentrations as assessed by the area under the curve (AUC) (P < 0.05) and an increase in BMR (AUC, P < 0.05) were observed during GH treatment. The overall GH-induced changes were due to marked changes in serum leptin concentrations and BMR after 6 weeks of treatment. After 9 months of GH treatment there was a significant reduction in body fat (BF) while serum leptin concentrations and BMR did not differ from baseline values. Leptin mRNA levels did not change over the study period. We speculate that long-term GH treatment induces a new energy balance steady state with decreased BF stores. The effects of GH on the leptin system is suggested to be of importance for the maintenance of a lower BF mass.

Abdomen↗
PubMed1997

The effect of metoprolol treatment on insulin sensitivity and diurnal plasma hormone levels in hypertensive subjects.

To evaluate the effect of metoprolol on insulin sensitivity and diurnal plasma hormone levels, seven mildly hypertensive subjects were investigated (four men and three women, age 52 +/- 8, body mass index 25.4 +.- 1.9, mean +/- SD). The study had a placebo-controlled, double-blind, crossover design with 6 weeks' metoprolol treatment (100 mg b.i.d) vs. placebo. At the end of each treatment period 24-h blood samples were collected continuously for diurnal analysis of hormone levels and a hyperinsulinaemic euglycaemic clamp combined with [3-3H]-D-glucose infusion was performed. Insulin sensitivity was evaluated by means of three different methods: diurnal plasma insulin and glucose levels; glucose consumption; and insulin sensitivity index during euglycaemic clamp conditions. Fasting blood glucose and insulin concentrations as well as mean plasma diurnal levels of insulin, growth hormone, testosterone and cortisol were similar after placebo and metoprolol treatment, whereas noradrenaline and adrenaline levels were significantly increased after metoprolol. During the clamp, plasma insulin was significantly higher after metoprolol treatment than after placebo treatment (56 +/- 3 vs. 64 +/- 2 mU L(-1), P < 0.05). Consequently, the insulin sensitivity index [glucose infusion rate (GIR)/ plasma insulin] was lower after metoprolol treatment (16.1 +/- 2.6 vs. 10.2 +/- 1.2, P < 0.05), although GIR was not significantly changed. We suggest that the insulin sensitivity index may not accurately reflect the insulin effect as the plasma level of insulin was significantly increased during insulin infusion but not at 24 h, possibly because of alteration of distribution and/or degradation rate of exogenous insulin. Thus, the likelihood of metoprolol inducing insulin resistance in hypertensive subjects may be less than previously proposed.

Adult↗
PubMed1997

Estrogen replacement therapy decreases hyperandrogenicity and improves glucose homeostasis and plasma lipids in postmenopausal women with noninsulin-dependent diabetes mellitus.

Hyperandrogenicity in women is closely associated with insulin resistance and a risk factor for cardiovascular disease and noninsulin-dependent diabetes mellitus (NIDDM). Therefore, 25 postmenopausal women with NIDDM and sex hormone-binding globulin values less than 60 nmol/L, as an indicator of a moderate hyperandrogenicity, were treated with 2 mg 17-beta-estradiol orally for 3 months in a double-blind, cross-over, placebo-controlled trial. During the last 16 days of active treatment, 1 mg norethisterone acetate was added for 10 days for endometrial protection. Blood glucose, glycosylated hemoglobin, insulin, c-peptide, lipoprotein profile, sex steroid hormones, GH, and insulin-like growth factor I (IGF-I) were measured, and insulin sensitivity was determined by the euglycemic hyperinsulinemic clamp method. All metabolic measurements were taken at baseline and after 68 days of active or placebo treatment. Estradiol treatment, compared with the placebo period, was followed by a marked increase of sex hormone-binding globulin and a decrease of free testosterone. Blood glucose, glycosylated hemoglobin, c-peptide, total cholesterol, low-density lipoprotein cholesterol, and IGF-I decreased significantly (P < 0.01-P < 0.001), whereas high-density lipoprotein cholesterol rose (P < 0.001). In conclusion, estrogen replacement therapy in postmenopausal women with NIDDM ameliorated hyperandrogenicity, and this was accompanied by marked improvements in glucose homeostasis and lipoprotein profile.

Androgens↗
PubMed1997

Growth hormone treatment of abdominally obese men reduces abdominal fat mass, improves glucose and lipoprotein metabolism, and reduces diastolic blood pressure.

The most central findings in both GH deficiency in adults and the metabolic syndrome are abdominal/visceral obesity and insulin resistance. Abdominal obesity is associated with blunted GH secretion and low serum insulin-like growth factor-I concentrations. GH treatment in GH-deficient adults has demonstrated favorable effects on most of the features of GH deficiency in adults, but it is not known whether GH can improve some of the metabolic aberrations observed in abdominal/visceral obesity. Thirty men, 48-66 yr old, with abdominal/visceral obesity were treated with recombinant human GH (rhGH) in a 9-month randomized, double-blind, placebo-controlled trial. The daily dose of rhGH was 9.5 micrograms/kg. Body fat was assessed from total body potassium, and abdominal sc and visceral adipose tissue was measured using computed tomography. The glucose disposal rate (GDR) was measured during an euglycemic, hyperinsulinemic glucose clamp. In response to the rhGH treatment, total body fat and abdominal sc and visceral adipose tissue decreased by 9.2 +/- 2.4%, 6.1 +/- 3.2%, and 18.1 +/- 7.6%, respectively. After an initial decrease in the GDR at 6 weeks, the GDR increased in the rhGH-treated group as compared with the placebo-treated one (P < 0.05). The mean serum concentrations of total cholesterol (P < 0.01) and triglyceride (P < 0.05) decreased, whereas blood glucose and serum insulin concentrations were unaffected by the rhGH treatment. Furthermore, diastolic blood pressure decreased and systolic blood pressure was unchanged in response to rhGH treatment. This trial has demonstrated that GH can favorably affect some of the multiple perturbations associated with abdominal/visceral obesity. This includes a reduction in abdominal/visceral obesity, an improved insulin sensitivity, and favorable effects on lipoprotein metabolism and diastolic blood pressure.

Adipose Tissue↗
PubMed1996

Influence of smoking on hormone secretion in obese and lean female smokers.

Smoking exerts influences on the secretion of several hormones which are abnormal in obesity. Previous studies have mainly been performed in non-obese men, and data from non-obese and obese women are scarce. The aim of the present study was therefore to identify the effect of smoking on hormone secretions in obese and lean female smokers. The study was performed in 10 obese and 8 lean, premenopausal, healthy smokers. All subjects were tested once under experimental and once under control conditions (not smoking) in randomized order. The women smoked two non-filtered cigarettes during 4 minutes each. Blood pressure and heart rate were measured 30 minutes before smoking, at the start of smoking (time 0) and then after 5, 10, 20, 30, 45 and 60 minutes. Blood samples were taken for determination of serum concentrations of adrenocorticotropic hormone (ACTH), cortisol, prolactin (PRL), growth hormone (GH) and thyroid stimulating hormone (TSH) at the same time points except at 5 minutes. Heart rate rose in both groups during smoking. Systolic and diastolic blood pressure was increased only in the obese subjects. Cortisol and ACTH increased in both groups, while TSH, PRL and GH were unchanged in both groups. We conclude that lean and obese smoking women seem to respond rather similarly to smoking in the hemodynamic and endocrine variables measured in this report with the possible exception of blood pressure where the obese women tended to show more pronounced increases.

Adrenocorticotropic Hormone↗
PubMed1996

Mental distress, obesity and body fat distribution in middle-aged men.

Previous epidemiological studies have suggested that psychiatric symptoms are associated with obesity and abdominal distribution of body fat in women. The aim of the present study was to examine this in middle-aged men. In 1992 a cluster selected cohort of 1040 men born in 1944 (participation rate 79.9%) was examined. Registrations of symptoms of depression and anxiety, sleep disturbances, psychosomatic disease as well as degree of life satisfaction were analyzed in relation to body mass index (BMI) and the waist/hip circumference ratio (WHR). In univariate analyses both BMI and WHR correlated with these factors. BMI and WHR were, however, closely interrelated (p = 0.61), necessitating analyses of separate, independent relationships in multivariate analyses. When adjusted for WHR all the significant relationships with BMI disappeared. In contrast the WHR, adjusted for BMI, showed remaining significant associations with the use of anxiolytics (p = 0.018), hypnotics (p = 0.029), antidepressive drugs (p = 0.008), degree of melancholy (p = 0.002), and life satisfaction (p = 0.002, negative), difficulties to sleep (p = 0.014) and fall asleep (p = 0.047), tendency to wake up from sleep (borderline, p = 0.070) and dyspepsia (p < 0.001). Since smoking and alcohol are known to influence on the WHR, these factors were, in addition to BMI, entered into the analyses as confounding variables. The mentioned associations then remained statistical significant (use of hypnotics borderline, p = 0.074) except difficulties to fall asleep and tendency to wake up. It was concluded that in contrast to BMI, the WHR is associated with symptoms of depression and anxiety with associated sleep disturbances, as well as psychosomatic symptoms and dissatisfaction. It was hypothesized that the mechanism involved might be increased secretion of cortisol, directing storage fat to central adipose tissue depots.

Adipose Tissue↗
PubMed1996

Inhibition of cortisol secretion by dexamethasone in relation to body fat distribution: a dose-response study.

There is now evidence of a hypersensitive hypothalamo-pituitary-adrenal (HPA) axis in subjects with an elevated waist/hip circumference ratio (WHR), an indicator of the centralization of body fat stores. The activity of the HPA axis is regulated by central glucocorticoid receptors, whose activity can be tested by the administration of exogenous glucocorticoids, which normally inhibit cortisol secretion. In this study, dexamethasone (dex) was administered in random order in doses of 0.05, 0.125, 0.25 and 0.5 mg at 10 p.m. with measurements of serum cortisol in the morning (8 a.m.) of this and the following day. The test was performed on 22 apparently healthy men, 40 to 60 years of age, recruited from laboratory personnel, outpatient clinics or advertisements in a newspaper. Eight had a body mass index (BMI) (kg/m2) of < 25 and 14 of > 25. Twelve men had a waist hip ratio (WHR) of < 1.0 and 10 men had a WHR of > 1.0. Cortisol values at baseline were correlated inversely with WHR and were usually lower in men with a high (> 1.0) rather than a low than low (< 1.0) WHR after dex inhibition. There was apparently no inhibition by dex at 0.05 and 0.125 mg on average in men with a WHR of > 1.0. In addition, the inhibition at 0.5 mg dex correlated negatively with the WHR and was significantly lower (p < 0.05) in men with a WHR of > 1.0 than in men with a WHR of < 1.0. None of these differences or relationships was found to be dependent on BMI. It is concluded that men with an elevated WHR experience a decrease in the inhibition of cortisol secretion by dex. It is suggested that this could explain or contribute to the elevated sensitivity of their HPA axis. Furthermore, lower morning cortisol concentrations suggest a change in diurnal secretion patterns.

Adult↗
PubMed1996

Two weeks of daily injections and continuous infusion of recombinant human growth hormone (GH) in GH-deficient adults. II. Effects on serum lipoproteins and lipoprotein and hepatic lipase activity.

Recombinant human growth hormone (GH) administered as daily subcutaneous (SC) injections has been shown to affect serum lipoproteins in GH-deficient subjects. However, the effects of continuous infusion of GH on serum lipoproteins have not been investigated in GH-deficient adults. The aim of the present study was to compare effects of daily injections and continuous infusion of GH on lipoprotein metabolism. Recombinant human GH (0.25 U/kg/wk) was administered to nine GH-deficient adult men during a period of 14 days in two different ways, ie, as a daily SC injection at 8:00 PM and as a continuous SC infusion, with 1 month of washout between the treatments. Blood samples and tests were performed in the morning after an overnight fast before the start of GH treatment (day 0) and on day 2 and day 14 of treatment. Abdominal SC adipose tissue lipoprotein lipase (LPL), postheparin plasma LPL, and hepatic lipase (HL) activity were measured 120 minutes after the intake of 100 g glucose. Adipose tissue LPL activity decreased and postheparin plasma HL activity increased after 14 days of GH treatment irrespective of the mode of GH administration, whereas GH treatment had no effect on postheparin plasma LPL activity. Serum triglyceride and very-low-density lipoprotein (VLDL) triglyceride concentrations increased during GH treatment. However, VLDL triglyceride concentrations increased to a greater degree during treatment with daily GH injections than during continuous infusion of GH. Serum apolipoprotein (apo) B and low-density lipoprotein (LDL) cholesterol concentrations decreased during treatment with daily GH injections, but were not significantly affected by continuous GH infusion. Thus, apo B and LDL cholesterol concentrations were lower after daily GH injections versus continuous GH infusion. Serum lipoprotein(a) [Lp(a)] and apo E concentrations increased during both modes of GH treatment. However, continuous infusion of GH resulted in a more marked increase in Lp(a) and apo E concentrations than daily GH injections. Minor effects were observed on serum apo A-I concentrations but high-density lipoprotein (HDL) cholesterol concentrations were not affected. In conclusion, GH treatment of GH-deficient men influenced adipose tissue LPL and postheparin plasma HL activity, as well as serum lipoprotein concentrations. Moreover, continuous GH infusion and daily GH injections differed with respect to the magnitude of effects on several lipoprotein fractions including VLDL triglycerides, LDL cholesterol, apo B, apo E, and Lp(a) concentrations.

Adult↗
PubMed1996

Assimilation of triglycerides in subcutaneous and intraabdominal adipose tissues in vivo in men: effects of testosterone.

To determine the effects of testosterone (T) on lipid assimilation in different adipose tissue depots, T (250 mg, im) was given to 17 middle-aged men 5 days before abdominal surgery. Twenty-four hours before surgery, 10 microCi labeled oleic acid in 80 g milk fat were administered orally. Lipid radioactivity was measured in adipose tissue biopsies from abdominal ac, omental, and retroperitoneal adipose tissues. Subcutaneous, visceral (omental plus mesenteric), and retroperitoneal adipose tissue masses were determined using computerized tomography scans at 22 levels. Sixteen men who were not treated with T served as controls. T administration was followed by an increase in serum concentrations from 17.7 +/- 1.1 to 32.6 +/- 1.8 nmol/L (P < 0.001) and a marked (> 50%) reduction compared with controls in lipid radioactivity in omental and retroperitoneal adipose tissues, but not in sc adipose tissue. In controls, sc, visceral, and retroperitoneal adipose tissues assimilated 59.2 g (73.4%), 16.9 g (20.9%), and 4.6 g (5.7%), respectively, of the orally administered fat. In the T-treated men, this was changed to 73.5 g (88.8%), 6.4 g (7.7%), and 2.9 g (3.5%), respectively. It was concluded that T inhibits triglyceride assimilation in intra-abdominal depots and apparently directs this lipid to sc fat in men.

Abdomen↗
PubMed1995

Blockade of the glucocorticoid receptor with RU 486: effects in vitro and in vivo on human adipose tissue lipoprotein lipase activity.

Cortisol is known to induce lipoprotein lipase (LPL) activity in human adipose tissue in vitro and in vivo such as in Cushing's syndrome. The significance of the glucocorticoid receptor (GR) for this induction was evaluated in the present study. The synthetic steroid molecule RU 486, a potent glucocorticoid antagonist, was used as a tool to block the GR, in vitro and in vivo. In addition to LPL activity, glucose tolerance, blood pressure and plasma lipids, all variables influenced by cortisol, were studied in order to evaluate the peripheral antiglucocorticoid activity of RU 486 in vivo, in man. Addition of both cortisol and RU 486 to incubations of human adipose tissue pieces significantly inhibited the increase in LPL activity that could be induced by cortisol alone (p < 0.01). In a ten-fold molarity excess RU 486 totally abolished cortisol action (p < 0.01). With cortisol and RU 486 in equimolar concentrations the RU 486 blockade was probably incomplete and LPL activity induced (p < 0.05). The results imply that the stimulating effect of cortisol on LPL activity in human adipose tissue is mediated via the GR. Administration of 400 mg RU 486 at 2200 hours on two consecutive days to healthy men caused a significant rise in serum cortisol levels measured at 0800 hours (p < 0.05). The mean LPL activity in the subcutaneous abdominal adipose tissue remained unchanged. The mean level of serum triglycerides decreased significantly (p < 0.01) and there was a negative correlation between change in LPL activity and change in triglyceride levels (r = -0.73, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1995

Testosterone and regional fat distribution.

The effects of testosterone treatment of abdominally obese men have been assessed by evaluating the following parameters: The metabolic activity of different adipose tissue regions in vivo (using lipid label as a tracer) and in vitro (measuring lipoprotein lipase (LPL) activity), the total and visceral adipose tissue mass, insulin sensitivity, fasting blood glucose, blood lipids, and blood pressure as well as prostate volume. Middle-aged men with abdominal obesity were treated with transdermal administration of testosterone (T), dihydrotestosterone (DHT) or placebo (P) during 9 months. The study was double-blind. Treatment with T was followed by an inhibited uptake of lipid label in adipose tissue triglycerides, a decreased LPL-activity and an increased turn-over rate of lipid label in the abdominal adipose tissue region in comparisons with the DHT and P groups. These effects on adipose tissue metabolism were not detected in the femoral adipose tissue region in any of the groups. T treatment was also followed by a specific decrease of visceral fat mass (measured by CT-scan), by increased insulin sensitivity (measured with the euglycemic glucose clamp), by a decrease in fasting blood glucose, plasma cholesterol and triglycerides as well as a decrease in diastolic blood pressure. In the DHT group an increased visceral mass was detected. No other changes in these variables were found in the DHT and P groups. There were no detectable changes in prostate volume (measured by ultra-sound), prostate specific antigen concentration, genito-urinary history or urinary flow measurements in any of the groups. It is suggested that T substitution to a selected group of men results in general metabolic and circulatory improvements. The prostate area needs further careful attention.

Adipose Tissue↗
PubMed1995

Assimilation and mobilization of triglycerides in subcutaneous abdominal and femoral adipose tissue in vivo in men: effects of androgens.

Studies on regional differences of adipose tissue metabolism have mainly been performed in vitro. To allow measurements of lipid uptake in vivo in man, radioactive label from [9,10-3H]oleic acid in 80 g orally administered milk fat was measured after 4 h in abdominal and femoral sc adipose tissues in 28 middle-aged, abdominally obese men. Radioactivity was measured in adipose tissue triglycerides extracted from needle biopsies. Lipoprotein lipase (LPL) activity was also measured. Uptake of label in triglycerides and LPL activity were higher (20% and 15%, respectively; P < 0.05) in the abdominal compared to the femoral adipose tissue region. The men were then randomly assigned to three groups, receiving testosterone (T), dihydrotestosterone, or placebo, for 9 months. After 2 months of treatment, the procedure of administration of label was repeated, this time using [U-14C]oleic acid as a marker. Measurements of radioactive label was then performed after 4 h and monthly up to 7 months. Supplementation with T was followed by an inhibited uptake of label in triglycerides (34%; P < 0.05), lower LPL activity (48%; P < 0.05), and a shorter t1/2 (30%; P < 0.05) in the abdominal adipose tissue region compared with the dihydrotestosterone and placebo groups. No significant effect of T on triglyceride uptake, LPL activity, or t1/2 was found in sc femoral adipose tissue. It was concluded that the turnover rate of depot triglycerides is more rapid in abdominal compared to femoral sc adipose tissue in men. Furthermore, T supplementation inhibits triglyceride uptake and LPL activity and causes a more rapid turnover of triglycerides only in the sc abdominal adipose tissue region. These results demonstrate the marked effects of T on adipose tissue metabolism in vivo and suggest that T is an important regulator of the proportion of depot fat mass in central and peripheral adipose tissue in men.

Abdomen↗
PubMed1994

Growth hormone secretion after testosterone administration to men with visceral obesity.

Visceral obesity in men has been reported to be characterized by low testosterone (T) and insulin-like growth factor I (IGF-I) concentrations, the latter suggesting a relative growth hormone (GH) deficiency. Since T and GH-secretions are interrelated, men with visceral obesity were substituted with T for 14 days, and diurnal secretion pattern of GH as well as IGF-I concentrations, and metabolic variables were followed. Visceral obese men were characterized by a decreased total GH secretion and diminished peak amplitude, size, and number. T-substitution was followed by elevation of IGF-I levels. The IGF-I increase correlated with the elevation of T-concentration, and was most pronounced in men with the lowest concentrations of free T from the outset. There were no detectable changes in total quantity, amplitude, size or number of peaks of GH secretion. Glucose, chlolesterol and triglycerides as well as diastolic blood pressure decreased. There were no changes in thyroid or hematology variables. T-substitution of visceral obese men is followed by an elevation of IGF-I concentrations. It is suggested that this might be due either to minor, non-detectable increases in GH secretion, or to direct effects of T on IGF-I concentrations. The regulatory mechanisms by which T-administration are leading to metabolic and anthropometric improvements, might be direct effects of T, with or without mediation via GH secretion.

Abdominal Fat↗
PubMed1994

Low dose continuously infused growth hormone results in increased lipoprotein(a) and decreased low density lipoprotein cholesterol concentrations in middle-aged men.

OBJECTIVE: Animal studies have shown that slight increases in basal GH concentrations may result in changes in lipoprotein metabolism. Such changes in GH secretion have been observed in physiological and pathophysiological states such as fasting, uncontrolled diabetes and during oestrogen treatment. The aim of this study was to investigate the possible effects of increases in basal plasma GH concentrations on lipoprotein concentrations. DESIGNS: Recombinant human growth hormone (rhGH) was given as a continuous subcutaneous infusion in a low dose (0.02 U/kg/day) in an open study. PATIENTS: Eight middle-aged (42-59 years) overweight (body mass index: 26.1-33.8 kg/m2) but otherwise healthy men were studied over a period of 14 days. MEASUREMENTS: Blood samples were obtained after an over-night fast before and after 2, 7 and 14 days of treatment. Plasma and serum were separated and used for subsequent measurements of hormone and lipoprotein concentrations. On days 0, 7 and 14 of treatment, post-heparin plasma was also obtained for determinations of plasma lipoprotein lipase and hepatic lipase activities. In addition, a hyperinsulinaemic euglycaemic glucose clamp was performed on days 0 and 13 of the study. Fat biopsies from abdominal and gluteal fat depots were obtained for measurement of lipoprotein lipase activities on days 0 and 14 of the study. RESULTS: Serum GH concentrations increased to a steady level of 2-4 mU/l during treatment. Serum insulin-like growth factor-I (IGF-I) concentrations increased throughout the treatment period to twice the pretreatment levels. Plasma insulin and blood glucose concentrations increased on day 2 of treatment. After 7 and 14 days of treatment blood glucose concentrations were not different from pretreatment levels, but plasma insulin concentrations were still elevated. Serum cholesterol and low density lipoprotein (LDL) cholesterol concentrations had decreased after 7 and 14 days of treatment. High density lipoprotein (HDL) cholesterol concentrations were not affected, but very low density lipoprotein (VLDL) cholesterol and triglyceride concentrations increased transiently at day 2 of treatment. Serum apolipoprotein (apo) A-I, apoB and apoE concentrations were not significantly affected. Serum lipoprotein(a) concentrations had increased by days 7 and 14 to 147 and 142% of pretreatment concentrations, respectively. Lipoprotein lipase and hepatic lipase activities in post-heparin plasma, as well as abdominal and gluteal adipose tissue lipoprotein lipase activities, were not affected. There was no significant change in glucose disposal rate estimated from the glucose clamp studies. CONCLUSIONS: A low dose infusion of GH results in marked changes in lipoprotein concentrations with a transient increase in VLDL cholesterol and thereafter in a decrease in LDL cholesterol. In addition, this low dose of GH resulted in marked increases in lipoprotein(a) concentrations. The observed effects of GH may partly involve changes in IGF-I and insulin secretion.

Adult↗