Impact on lipoprotein profile after long-term testosterone replacement in hypogonadal men

Does Intense Endurance Workout Have an Impact on Serum Levels of Sex Hormones in Males?

The benefits of physical activity and sports are widely known and proved to be crucial for overall health and well-being. In this research, the authors decided to measure the impact of endurance training in a professional male rowing team on the serum concentration levels of testosterone, estradiol, sex hormone binding globulin (SHBG) and nitric oxide (NO) and apolipoprotein A1 (Apo-A1). Proper levels of the serum concentration are necessary in order to maintain physical effectiveness. Authors analyzed the data and reviewed the former conterminous articles to find the possible mechanisms leading to changes of serum concentration of certain hormones and molecules. The direct effect of physical activity was a decrease in testosterone serum concentration (from 7.12 ± 0.4 to 6.59 ± 0.35 (ng/mL)), sex hormone binding globulin serum concentration (from 39.50 ± 2.48 to 34.27 ± 2.33 (nmol/L)), nitric oxide serum concentration (from 440.21 ± 88.64 to 432 ± 91.89 (ng/mL)), increase in estradiol serum concentration (from 78.2 ± 11.21 to 83.01 ± 13.21 (pg/mL)) and no significant increase in Apo-A1 serum concentration (from 2.63 ± 0.2 to 2.69 ± 0.21 (mg/mL)). Low testosterone concentration in OTS may be a consequence of increased conversion to estradiol, because gonadotropic stimulation is maintained. Apo-A1 serum concentration was measured due to a strong connection with testosterone level and its possible impact of decreasing cardiovascular risk.

Effect of Selective Androgen Receptor Modulator on Cholesterol Efflux Capacity, Size and Subspecies of HDL Particles

Context

Selective androgen receptor modulators (SARMs), because of their preferential muscle vs prostate selectivity, are being developed for muscle-wasting conditions. Oral SARMs suppress high-density lipoprotein cholesterol (HDL-C) but their effects on functional capacity and atherogenic potential of HDL particles are unknown.

Objective

To determine the effects of an oral SARM (OPK-88004) on cholesterol efflux capacity, HDL particle number and size, apolipoprotein particle number and size and HDL subspecies

Methods

We measured cholesterol efflux capacity (CEC); HDL particle number and size; APOB; APOA1; and protein-defined HDL subspecies associated with coronary heart disease (CHD) risk in men, who had undergone prostatectomy for low-grade prostate cancer during 12-week treatment with placebo or 1, 5, or 15 mg of an oral SARM (OPK-88004).

Results

SARM significantly suppressed HDL-C (P < .001) but HDL particle size did not change significantly. SARM had minimal effect on CEC of HDL particles (change + 0.016, –0.036, +0.070, and –0.048%/µmol-HDL/L^–1 at 0, 1, 5, and 15 mg SARM, P = .045). SARM treatment suppressed APOAI (P < .001) but not APOB (P = .077), and reduced APOA1 in HDL subspecies associated with increased (subspecies containing α2-macroglobulin, complement C3, or plasminogen) as well as decreased (subspecies containing APOC1 or APOE) CHD risk; relative proportions of APOA1 in these HDL subspecies did not change. SARM increased hepatic triacylglycerol lipase (HTGL) (P < .001).

Conclusion

SARM treatment suppressed HDL-C but had minimal effect on its size or cholesterol efflux function. SARM reduced APOA1 in HDL subspecies associated with increased as well as decreased CHD risk. SARM-induced increase in HTGL could contribute to HDL-C suppression. These data do not support the simplistic notion that SARM-associated suppression of HDL-C is necessarily proatherogenic; randomized trials are needed to determine SARM’s effects on cardiovascular events.

Dynamic Impact of Hormone Therapy on Laboratory Values in Transgender Patients over Time

BACKGROUND

Known physiological changes occur while transgender patients are taking hormone therapy (HT). However, knowledge is limited about when laboratory values stabilize and if there are any long-term impacts, making it challenging for physicians to provide adequate gender-affirming care. We aim to analyze laboratory values with HT use over 5 years and after discontinuation of HT to define when values achieve stability.

METHODS

We performed a multicenter retrospective analysis of 126 transgender women (TW) and 91 transgender men (TM) at consecutive clinic visits. Labs included complete metabolic panel, complete blood count, lipids, and hormone levels and were monitored for 5 years. Absolute measurement and percentage change from baseline were calculated for each analyte value. We collected the laboratory studies described from patients off HT and the duration of discontinuation to determine the time to return to baseline levels.

RESULTS

During HT, red blood cell (RBC; erythrocyte) indexes reach stable levels within 6 months (P < 0.001) and are unchanged long term. Some analytes such as HDL and platelets showed increases beyond the first year of HT in TW (P = 0.001 and P < 0.001, respectively). LDL and alanine aminotransferase increased beyond 1 year in TM (P < 0.005 and P < 0.001, respectively), whereas HDL decreased beyond 1 year (P < 0.001). Time for laboratory values to return to baseline occurred around 10 weeks.

CONCLUSIONS

Most analytes reach stable levels within 6 months (RBC and creatinine), whereas others change in the long term (LDL, HDL, platelets). This information can be used to guide physicians as they monitor their transgender patients in all stages of their progress through HT.

Effect of testosterone supplementation on nitroso-redox imbalance, cardiac metabolism markers, and S100 proteins expression in the heart of castrated male rats

The aim of this study was to investigate the effects of castration and testosterone supplementation on nitroso-redox status, cardiac metabolism markers, and S100 proteins expression in the heart of male rats. 50 male Wistar rats were randomized into five groups with ten animals each: group 1: control intact (CON); group 2: sham operated (Sh-O); group 3: sesame oil-treated rats (S-oil); group 4: gonadoectomized (GDX); and group 5: gonadoectomized rats treated with testosterone (GDX-T) for 8 weeks. Our results showed myofibrillar weaving, apoptosis, inflammation, and fibrosis (as reflected by increased activity of MMP 9 and MMP 2) in the heart of gonadoectomized rats. Testosterone supplementation restored the normal structure of the heart. In addition, a state of nitroso-redox imbalance was observed in the heart of castrated rats with increased NO (425.1 ± 322.8 vs. 208 ± 67.06, p ˂ 0.05) and MDA (33.18 ± 9.45 vs. 22.04 ± 7.13, p ˂ 0.05) and decreased GSH levels (0.71 ± 0.13 vs. 1.09 ± 0.19, p = 0.001). Testosterone treatment leads to a re-establish of only NO levels (425.1 ± 322.8 vs. 210.4 ± 114.3, p > 0.05). Markers of cardiac metabolism showed an enhancement of LDH activity (12725 ± 4604 vs. 5381 ± 3122, p ˂ 0.05) in the heart of castrated rats. This was inversed by testosterone replacement (12725 ± 4604 vs. 5781 ± 5187, p ˂ 0.05). Furthermore, castration induced heart's accumulation of triglycerides (37.24 ± 6.17 vs. 27.88 ± 6.47, p ˂ 0.05) and total cholesterol (61.44 ± 3.59 vs. 54.11 ± 7.55, p ˂ 0.05), which were significantly reduced by testosterone supplementation (29.03 ± 2.47 vs. 37.24 ± 6.17, p ˂ 0.05) and (47.9 ± 4.15 vs. 61.44 ± 3.59, p ˂ 0.001). Cardiomyocytes of castrated rats showed a decreased immunoexpression of S100 proteins compared to control animals. A restoration of S100 proteins immunostaining in cardiomyocyte cytoplasm was observed after testosterone supplementation. These findings confirm the deleterious effects of testosterone deficiency on cardiac function and highlight the involvement of nitric oxide, metalloproteinases 2 and 9, and S100 proteins.

Association between testosterone levels and the metabolic syndrome in adult men

OBJECTIVE

To evaluate the relationship between testosterone levels and the metabolic syndrome (MS) in men older than 45 years.

METHODS

Six hundred and sixty men (45-70 years) selected from 2906 participants of a population screening for prostate cancer were included in this study. Testosterone and the components of MS were assessed in all men. MS was diagnosed according to NCEP-ATP III criteria. Triglycerides (TG)/HDL-cholesterol (chol) index was calculated.

RESULTS

The presence of MS was inversely associated with testosterone (χ2, p < 0.001), independently of age (OR 0.802, CI 95%: 0.724-0.887, p < 0.0001). Hypertension was the most frequent abnormality observed followed by elevated TG and waist circumference (WC). Testosterone correlated positively with HDL-chol (r: 0.14, p < 0.0001) and negatively with body mass index (BMI)(r: -0.29, p < 0.0001), WC (r: -0.26, p < 0.0001), TG (r: -0.20, p < 0.0001), TG/HDL-chol (r: -0.20, p < 0.0001), glucose (r: -0.11, p = 0.005) and MS score (r: -0.23, p < 0.0001).

CONCLUSIONS

Our results show that in men older than 45 years, as long as testosterone levels decline, the prevalence of MS increases, independently of age. The correlations found between testosterone and four of the five components of MS, as well as with BMI and TG/HDL-chol ratio, a surrogate marker of insulin resistance, suggest considering male hypogonadism as a determinant of developmental abnormalities typical of MS.

The relationship between endogenous testosterone and lipid profile in middle-aged and elderly Chinese men

OBJECTIVE

To evaluate the relationship between serum total testosterone (TT) level and lipid profile after adjusting for some traditional confounding factors, free thyroid hormones and TSH in Chinese men.

METHODS

This was a retrospective study based on an epidemiological investigation including 11 000 subjects. Bivariate and partial correlation analysis, multiple linear regression analysis, and a general linear model were used to assess the influence of TT on the lipid profile. Additionally, the odds ratios (ORs) (95% CIs) for hypertriglyceridemia and low HDL-C in relation to TT categories were calculated using logistic regression analysis.

RESULTS

A total of 4114 subjects whose mean age was 56.04±8.75 years were finally analyzed. There was a significant linear trend toward lower total cholesterol (TC), lower triglycerides (TG), and higher HDL-C with increasing serum TT, which remained significant after adjusting for age, BMI, fasting blood glucose, systolic blood pressure, free triiodothyronine, free thyroxine, and TSH. Compared with the bottom quartile of TT, the adjusted OR (95% CI) for hypertriglyceridemia and low HDL-C was 0.082 (0.048-0.138, P=0.000) and 0.669 (0.503-0.891, P=0.006) respectively in the top quartile of TT.

CONCLUSIONS

TT was correlated negatively and linearly with TC, TG, and LDL-C and positively and linearly with HDL-C. Low TT might have adverse effects on the lipid profile and thus represent a risk factor for hypercholesterolemia, hypertriglyceridemia, high LDL-C, and low HDL-C, suggesting the importance of maintaining an appropriate TT level in men.

Independent effects of testosterone on lipid oxidation and VLDL-TG production: a randomized, double-blind, placebo-controlled, crossover study

Low testosterone (T) levels in men have been shown to predict development of the metabolic syndrome, but the effects of T on lipid metabolism are incompletely understood. In a randomized, double-blind, placebo-controlled, crossover study, 12 healthy, young males received gonadotropin-releasing hormone agonist treatment 1 month prior to 3 of 4 trial days to induce castrate levels of T. On trial days, T gel was applied to the body containing either high or low physiological T dose or placebo. On the 4th trial day, participants constituted their own eugonadal controls. Each study comprised a 5-h basal period and a 3-h hyperinsulinemic-euglycemic clamp. Short-term hypogonadism did not affect VLDL triglyceride (TG) secretion, nor did it affect VLDL-TG concentrations. It was, however, characterized by lower total lipid oxidation. In addition, acute rescue with high physiological T increased VLDL-TG secretion during both basal and clamp conditions. These data show that T can act through fast nongenomic pathways in the liver. In addition, the early hypogonadal state is characterized by decreased total lipid oxidation, but whether these changes represent early hypogonadal metabolic dysfunction warrants further investigations. T is not a major determinant of resting VLDL-TG kinetics in men.

Dihydrotestosterone regulating apolipoprotein M expression mediates via protein kinase C in HepG2 cells

Background

Administration of androgens decreases plasma concentrations of high-density lipid cholesterol (HDL-C). However, the mechanisms by which androgens mediate lipid metabolism remain unknown. This present study used HepG2 cell cultures and ovariectomized C57BL/6 J mice to determine whether apolipoprotein M (ApoM), a constituent of HDL, was affected by dihydrotestosterone (DHT).

Methods

HepG2 cells were cultured in the presence of either DHT, agonist of protein kinase C (PKC), phorbol-12-myristate-13-acetate (PMA), blocker of androgen receptor flutamide together with different concentrations of DHT, or DHT together with staurosporine at different concentrations for 24 hrs. Ovariectomized C57BL/6 J mice were treated with DHT or vehicle for 7d or 14d and the levels of plasma ApoM and livers ApoM mRNA were measured. The mRNA levels of ApoM, ApoAI were determined by real-time RT-PCR. ApoM and ApoAI were determined by western blotting analysis.

Results

Addition of DHT to cell culture medium selectively down-regulated ApoM mRNA expression and ApoM secretion in a dose-dependent manner. At 10 nM DHT, the ApoM mRNA levels were about 20% lower than in untreated cells and about 40% lower at 1000 nM DHT than in the control cells. The secretion of ApoM into the medium was reduced to a similar extent. The inhibitory effect of DHT on ApoM secretion was not blocked by the classical androgen receptor blocker flutamide but by an antagonist of PKC, Staurosporine. Agonist of PKC, PMA, also reduced ApoM. At 0.5 μM PMA, the ApoM mRNA levels and the secretion of ApoM into the medium were about 30% lower than in the control cells. The mRNA expression levels and secretion of another HDL-associated apolipoprotein AI (ApoAI) were not affected by DHT. The levels of plasma ApoM and liver ApoM mRNA of DHT-treated C57BL/6 J mice were lower than those of vehicle-treated mice.

Conclusions

DHT directly and selectively down-regulated the level of ApoM mRNA and the secretion of ApoM by protein kinase C but independently of the classical androgen receptor.

Long-term Safety of Testosterone and Growth Hormone Supplementation: A Retrospective Study of Metabolic, Cardiovascular, and Oncologic Outcomes

Background

Clinical research into the effects of hormonal supplementation has tended to focus on beneficial changes in anthropometric measures. There are fewer data on long-term safety with extended hormonal supplementation.

Methods

As part of a retrospective database survey, clinical outcomes were tabulated among patients who received at least 1 year of testosterone and/or growth hormone (GH) supplementation. In patients who were treated for at least 2 years, changes in markers of glucose and lipid metabolism were analyzed with and without concomitant use of oral hypoglycemics and statins.

Results

In 263 patients (mean age 56) treated for at least 2 years, the only statistically significant effect on markers of glucose metabolism was an increase in glycated hemoglobin (still within normal limits) in patients receiving GH alone or in combination with testosterone but without oral hypoglycemics; with or without hypoglycemics, insulin levels showed no significant change. The only significant effects on markers of lipid metabolism were decreases in total cholesterol and low-density lipoprotein (LDL) in patients receiving combined testosterone and GH without statins. Decreases in LDL were significant in both the statin and non-statin groups; decreases in triglycerides were significant only in the statin group. In 531 patients treated for at least 1 year (mean age 54), the overall incidence of adverse clinical outcomes (prostate disease, diabetes, cardiovascular disease, cancer) was 1.3%.

Conclusions

In this retrospective survey, extended testosterone and/or GH supplementation did not adversely affect metabolic markers or clinical outcomes.

Keywords

Safety; Testosterone; Growth hormone; Supplementation

A higher burden of small low-density lipoprotein particles is associated with profound changes in the free androgen index in male adolescents

From a young age, males are at higher cardiovascular risk than females. Dyslipidemia, including a higher burden related to small low-density lipoproteins (LDL), plays an important role in precipitating atherosclerosis in both males and females. We investigated sex differences in atherogenic lipoprotein burden and the independent predictors of LDL particle size in children and adolescents. We measured the concentrations of total testosterone, sex hormone-binding globulin, estradiol, total cholesterol, triglyceride, LDL cholesterol, HDL cholesterol, and LDL particle size in 135 children and adolescents (67 boys, 68 girls). The free androgen index was significantly and negatively correlated with LDL particle size (r = -0.273, P = 0.026) in boys, but estrogen and LDL particle size were not related. In a stepwise multiple regression analysis adjusted for body mass index, age, and homeostasis model assessment for insulin resistance, free androgen index was still an independent predictor of LDL particle size in boys (R(2) = 0.075, P = 0.026). The prominent decrease in LDL particle size along with increased testosterone concentrations in males might explain why they are more likely to display atherogenic dyslipidemia from adolescence.

Gender differences in lipid metabolism and the effect of obesity

There are many differences between men and women, and between lean and obese subjects, in fatty acid and very low-density lipoprotein triglyceride and apolipoprotein B-100 metabolism. Currently, observations in this area are predominantly descriptive. The mechanisms responsible for sexual dimorphism in lipid metabolism are largely unknown.

Partial androgen deficiency, depression and testosterone treatment in aging men

This study provides a critical review of the literature on depressive symptoms of partial androgen deficiency (PADAM) and their treatment with Testosterone (T). PADAM in aging males is responsible for a variety of behavioral symptoms, such as weakness, decreased libido and erectile dysfunction, lower psychological vitality, depressive mood, anxiety, insomnia, difficulty in concentrating, and memory impairment. The psychological and behavioural aspects of PADAM may overlap with signs and symptoms of major depression. Evidence of the relationship between androgen deficiency and male depression comes from studies that have assessed depression in hypogonadal subjects, the association between low T level and male depressive illness, and the antidepressant action of androgen replacement. The etiology of depressive symptoms of PADAM is multifactorial, and results from the interaction of the biological and psychosocial changes that take place during the mid-life transition. Although data derived from androgen treatment trials and androgen replacement do not support T treatment or replacement as more efficacious than placebo for major depressive disorder (MDD), the clinical impression is that, in some sub-threshold depressive syndromes, T may lead to antidepressant benefits.

Gene expression analyses in cynomolgus monkeys provides mechanistic insight into high-density lipoprotein-cholesterol reduction by androgens in primates

Androgens increase muscle mass, decrease fat mass, and reduce high-density lipoprotein cholesterol (HDL), but the relationship between body composition, lipoprotein metabolism, and androgens has not been explained. Here we treated ovariectomized cynomolgus monkeys with 5alpha-dihydrotestosterone (DHT) or vehicle for 14 d and measured lipoprotein and triglycerides. Nuclear magnetic resonance analysis revealed that DHT dose-dependently reduced the cholesterol content of large HDL particles and decreased mean HDL particle size (P < 0.01) and also tended to lower low-density lipoprotein cholesterol without altering other lipoprotein particles. Liver and visceral fat biopsies taken before and after DHT treatment for 1 or 14 d were analyzed by genome-wide microarrays. In liver, DHT did not alter the expression of most genes involved in cholesterol synthesis or uptake but rapidly increased small heterodimer partner (SHP) RNA, along with concomitant repression of CYP7A1, a target of SHP transcriptional repression and the rate-limiting enzyme in bile acid synthesis. DHT regulation of SHP and CYP7A1 also occurs in rats, indicating a conserved mechanism. In adipose tissue, pathway analyses suggested coordinate regulation of adipogenesis, tissue remodeling, and lipid homeostasis. Genes encoding IGF-I and beta-catenin were induced, as were extracellular matrix, cell adhesion, and cytoskeletal components, whereas there was consistent down-regulation of genes involved in triacylglycerol metabolism. Interestingly, cholesterol ester transfer protein RNA was induced rapidly in monkey adipose tissue, whereas its inhibitor apolipoprotein CI was repressed. These data provide insight into the androgenic regulation of lipoprotein homeostasis and suggest that changes in adipose lipoprotein metabolism could contribute to HDL cholesterol reduction.

Physiological Basis of Fatigue

This work summarizes our knowledge of the physiological basis of fatigue and the effects of exercise and pharmacological interventions on fatigue. Fatigue may be defined as physical and/or mental weariness resulting from exertion, that is, an inability to continue exercise at the same intensity with a resultant deterioration in performance. The concept of deconditioning in patients is discussed as well as the implications for their rehabilitation and exercise. Because fatigue may result from a number of causes, including loss of muscle mass, deconditioning, nutritional deficiencies, oxygen delivery, and anemia, it should be treated comprehensively. Antifatigue therapy should be the standard of care for most chronic conditions associated with fatigue.

Atherosclerosis is enhanced by testosterone deficiency and attenuated by CETP expression in transgenic mice

In this work, we investigated the impact of testosterone deficiency and cholesteryl ester transfer protein (CETP) expression on lipoprotein metabolism and diet-induced atherosclerosis. CETP transgenic mice and nontransgenic (nTg) littermates were studied 4 weeks after bilateral orchidectomy or sham operation. Castrated mice had an increase in the LDL fraction (+36% for CETP and +79% for nTg mice), whereas the HDL fraction was reduced (-30% for CETP and -11% for nTg mice). Castrated mice presented 1.7-fold higher titers of anti-oxidized LDL (Ox-LDL) antibodies than sham-operated controls. Plasma levels of CETP, lipoprotein lipase, and hepatic lipase were not changed by castration. Kinetic studies showed no differences in VLDL secretion rate, VLDL-LDL conversion rate, or number of LDL and HDL receptors. Competition experiments showed lower affinity of LDL from castrated mice for tissue receptors. Diet-induced atherosclerosis studies showed that testosterone deficiency increased by 100%, and CETP expression reduced by 44%, the size of aortic lesion area in castrated mice. In summary, testosterone deficiency increased plasma levels of apolipoprotein B-containing lipoproteins (apoB-LPs) and anti-OxLDL antibodies, decreased LDL receptor affinity, and doubled the size of diet-induced atherosclerotic lesions. The expression of CETP led to a milder increase of apoB-LPs and reduced atherosclerotic lesion size in testosterone-deficient mice.

Testosterone replacement in hypogonadal men with angina improves ischaemic threshold and quality of life

BACKGROUND

Low serum testosterone is associated with several cardiovascular risk factors including dyslipidaemia, adverse clotting profiles, obesity, and insulin resistance. Testosterone has been reported to improve symptoms of angina and delay time to ischaemic threshold in unselected men with coronary disease.

OBJECTIVE

This randomised single blind placebo controlled crossover study compared testosterone replacement therapy (Sustanon 100) with placebo in 10 men with ischaemic heart disease and hypogonadism.

RESULTS

Baseline total testosterone and bioavailable testosterone were respectively 4.2 (0.5) nmol/l and 1.7 (0.4) nmol/l. After a month of testosterone, delta value analysis between testosterone and placebo phase showed that mean (SD) trough testosterone concentrations increased significantly by 4.8 (6.6) nmol/l (total testosterone) (p = 0.05) and 3.8 (4.5) nmol/l (bioavailable testosterone) (p = 0.025), time to 1 mm ST segment depression assessed by Bruce protocol exercise treadmill testing increased by 74 (54) seconds (p = 0.002), and mood scores assessed with validated questionnaires all improved. Compared with placebo, testosterone therapy was also associated with a significant reduction of total cholesterol and serum tumour necrosis factor alpha with delta values of -0.41 (0.54) mmol/l (p = 0.04) and -1.8 (2.4) pg/ml (p = 0.05) respectively.

CONCLUSION

Testosterone replacement therapy in hypogonadal men delays time to ischaemia, improves mood, and is associated with potentially beneficial reductions of total cholesterol and serum tumour necrosis factor alpha.

Serum lipids and estrogen receptor gene polymorphisms in male-to-female transsexuals: effects of estrogen treatment

The effects of chronic administration of estrogens on the lipid profile in males are not fully understood. We have studied the effect of chronic administration of estrogens on the lipid profile in a group of transsexual (TS) Canarian men who were taking estrogens and anti-androgens for a minimum of 3 years. In this cross-sectional study of cases (n=27) and controls (n=26), plasma lipid profile and selected biochemical and hormonal features were studied. TS subjects had shorter stature than controls, and, after adjusting for height and weight, we found that they had lower values of serum free testosterone (FT) and higher estradiol (E2) levels than controls. The TS group had lower total and low-density lipoprotein (LDL) cholesterol and lower apoprotein B (Apo B) levels than the control group. Biochemistry was similar in both groups. The distribution of estrogen receptor gene polymorphisms (ER-Pvu and ER-Xba) was also similar in both groups. Serum Apo B concentration was related to ER-Xba polymorphism. No other association between lipid profile and the distribution of ER-Pvu and ER-Xba was found. We conclude that the chronic administration of estrogens in men could produce an increase in serum estradiol, a decrease in free testosterone levels, and a reduction in total cholesterol, LDL-cholesterol, and Apo B levels. The ER-Xba polymorphism may influence the Apo B response to exogenous estrogen in males.

Testosterone administration to men increases hepatic lipase activity and decreases HDL and LDL size in 3 wk

Testosterone administration to men is known to decrease high-density lipoprotein cholesterol (HDL-C) and the subclasses HDL(2) and HDL(3). It also might increase the number of small, dense, low-density lipoprotein cholesterol (LDL-C) particles in hypogonadal men. The decrease in HDL-C and in LDL-C size is potentially mediated by hepatic lipase activity, which hydrolyzes lipoprotein phospholipids and triacylglycerol. To determine how HDL-C and LDL-C particles are affected by testosterone administration to eugonadal men, testosterone was administered as a supraphysiological dose (600 mg/wk) for 3 wk to elderly, obese, eugonadal men before elective hip or knee surgery, and lipids were measured by routine methods and by density gradient ultracentrifugation. Hepatic lipase activity increased >60% above baseline levels, and HDL-C, HDL(2), and HDL(3) significantly declined in 3 wk. In addition, the LDL-C peak particle density and the amount of LDL-C significantly increased. Testosterone is therefore a potent stimulator of hepatic lipase activity, decreasing HDL-C, HDL(2), and HDL(3) as well as increasing LDL particle density changes, all associated with increased cardiovascular risk.