Obesity: Wu FC

Wang C, Nieschlag E, Swerdloff R, Behre HM, Hellstrom WJ, Gooren LJ, Kaufman JM, Legros JJ, Lunenfeld B, Morales A, Morley JE, Schulman C, Thompson IM, Weidner W, Wu FC, Anonymous00084, Anonymous00085, Anonymous00086, Anonymous00087, Anonymous00088. · Division of Endocrinology, Department of Medicine, Harbor-UCLA Medical Center, and Los Angeles BioMedical Research Institute, Torrance, CA 90509, USA. · J Androl. · Pubmed #18772485 No free full text.

This publication has no abstract.

Eckardstein A, Wu FC. · Institute of Clinical Chemistry, University Hospital of Zurich, Raemistrasse 100, CH-8091, Zurich, Switzerland. · Growth Horm IGF Res. · Pubmed #12914731 No free full text.

Abstract: Hypoandrogenemia in men and hyperandrogenemia in women are associated with increased risk of coronary artery disease but also with visceral obesity, insulin resistance, low high-density lipoprotein (HDL) cholesterol, elevated triglycerides, low-density lipoprotein (LDL) cholesterol and plasminogen activator inhibitor (PAI-1). These gender differences and confounders render the precise role of endogenous androgens in atherosclerosis unclear.Exogenous androgens, on the other hand, induce both apparently beneficial and deleterious effects on cardiovascular risk factors by decreasing serum levels of HDL-C, PAI-1 (apparently deleterious), Lp(a), fibrinogen, insulin, leptin and visceral fat mass (apparently beneficial) in men as well as women. However, androgen-induced declines in circulating HDL-C should not automatically be assumed to be pro-atherogenic, since it may reflect accelerated reverse cholesterol transport instead.Short-term application of supraphysiological doses of exogenous T can reduce the severity and frequency of angina pectoris and improve the electrocardiographic signs of myocardial ischaemia; long-term effects have not been investigated. Nonetheless, interpretations of the effects of pharmacological doses of androgens on arterial compliance and flow-mediated dilatation in particular must be treated with circumspection also because at physiological concentrations, beneficial, neutral, and detrimental effects on vascular reactivity can be observed.Testosterone exerts 'pro-atherogenic' effects on macrophage function by facilitating the uptake of modified lipoproteins and an 'anti-atherogenic' effect by stimulating efflux of cellular cholesterol to HDL.In the majority of animal experiments, exogenous testosterone exerted neutral or beneficial effects on the development of atherosclerosis.In conclusion, the overall effect of administration of testosterone on cardiovascular-disease risk is difficult to assess because androgens have such an extraordinary array of effects in vivo. When dealing with a complex multifactorial condition such as CAD, it is premature to assume that clinical benefits can be derived from manipulation of the sex steroid milieu - even when these assumptions are based on biologically plausible mechanisms or, indeed, on cross-sectional risk-factor observational data. Neither needs the therapeutic use of testosterone in men be restricted by concerns regarding cardiovascular side effects.

Wu FC, von Eckardstein A. · Department of Endocrinology, Manchester Royal Infirmary, University of Manchester, Manchester M13 9WL, United Kingdom. · Endocr Rev. · Pubmed #12700179 links to  free full text

Abstract: A significant and independent association between endogenous testosterone (T) levels and coronary events in men and women has not been confirmed in large prospective studies, although cross-sectional data have suggested coronary heart disease can be associated with low T in men. Hypoandrogenemia in men and hyperandrogenemia in women are associated with visceral obesity; insulin resistance; low high-density lipoprotein (HDL) cholesterol (HDL-C); and elevated triglycerides, low-density lipoprotein cholesterol, and plasminogen activator type 1. These gender differences and confounders render the precise role of endogenous T in atherosclerosis unclear. Observational studies do not support the hypothesis that dehydroepiandrosterone sulfate deficiency is a risk factor for coronary artery disease. The effects of exogenous T on cardiovascular mortality or morbidity have not been extensively investigated in prospective controlled studies; preliminary data suggest there may be short-term improvements in electrocardiographic changes in men with coronary artery disease. In the majority of animal experiments, exogenous T exerts either neutral or beneficial effects on the development of atherosclerosis. Exogenous androgens induce both apparently beneficial and deleterious effects on cardiovascular risk factors by decreasing serum levels of HDL-C, plasminogen activator type 1 (apparently deleterious), lipoprotein (a), fibrinogen, insulin, leptin, and visceral fat mass (apparently beneficial) in men as well as women. However, androgen-induced declines in circulating HDL-C should not automatically be assumed to be proatherogenic, because these declines may instead reflect accelerated reverse cholesterol transport. Supraphysiological concentrations of T stimulate vasorelaxation; but at physiological concentrations, beneficial, neutral, and detrimental effects on vascular reactivity have been observed. T exerts proatherogenic effects on macrophage function by facilitating the uptake of modified lipoproteins and an antiatherogenic effect by stimulating efflux of cellular cholesterol to HDL. In conclusion, the inconsistent data, which can only be partly explained by differences in dose and source of androgens, militate against a meaningful assessment of the net effect of T on atherosclerosis. Based on current evidence, the therapeutic use of T in men need not be restricted by concerns regarding cardiovascular side effects. Available data also do not justify the uncontrolled use of T or dehydroepiandrosterone for the prevention or treatment of coronary heart disease.

Wu FC, Tajar A, Pye SR, Silman AJ, Finn JD, O'Neill TW, Bartfai G, Casanueva F, Forti G, Giwercman A, Huhtaniemi IT, Kula K, Punab M, Boonen S, Vanderschueren D, Anonymous00058. · Department of Endocrinology, Manchester Royal Infirmary, Oxford Road, Manchester, United Kingdom. · J Clin Endocrinol Metab. · Pubmed #18270261 links to  free full text

Abstract: CONTEXT: The cause of declining testosterone (T) in aging men and their relationships with risk factors are unclear. OBJECTIVE: The objective of the study was to investigate the relationships between lifestyle and health with reproductive hormones in aging men. DESIGN: This was a baseline cross-sectional survey on 3200 community-dwelling men aged 40-79 yr from a prospective cohort study in eight European countries. RESULTS: Four predictors were associated with distinct modes of altered function: 1) age: lower free T (FT; -3.12 pmol/liter.yr, P < 0.001) with raised LH, suggesting impaired testicular function; 2) obesity: lower total T (TT; -2.32 nmol/liter) and FT (-17.60 pmol/liter) for body mass index (BMI; > or = 25 to < 30 kg/m(2)) and lower TT (-5.09 nmol/liter) and FT (-53.72 pmol/liter) for BMI 30 kg/m(2) or greater (P < 0.001-0.01, referent: BMI < 25 kg/m(2)) with unchanged/decreased LH, indicating hypothalamus/pituitary dysfunction; 3) comorbidity: lower TT (-0.80 nmol/liter, P < 0.01) with unchanged LH in younger men but higher LH in older men; and 4) smoking: higher SHBG (5.96 nmol/liter, P < 0.001) and LH (0.77 U/liter, P < 0.01) with increased TT (1.31 nmol/liter, P < 0.001) but not FT, compatible with a resetting of T-LH-negative feedback due to elevated SHBG. CONCLUSIONS: Complex multiple alterations in the hypothalamic-pituitary-testicular axis function exist in aging men against a background of progressive age-related testicular impairment. These changes are differentially linked to specific risk factors. Some risk factors operate independently of but others interact with age, in contributing to the T decline. These potentially modifiable risk factors suggest possible preventative measures to maintain T during aging in men.