RESUMEN
Previous studies have sought to associate the Pro12Ala variant of the peroxisome proliferator-activated receptor gamma2 (PPARG2) gene with type 2 diabetes, insulin resistance, and obesity, with controversial results. We have determined the Pro12Ala variant frequency in 370 nondiabetic Mexican Mestizo subjects and in five Mexican Amerindian groups and have investigated its possible association with lipid metabolism, insulin serum levels, and obesity in three of these populations. Two independent case-control studies were conducted in 239 nondiabetic individuals: 135 case subjects (BMI > or = 25 kg/m2) and 104 control subjects (BMI < 25 kg/m2). The PPARG2 Ala12 allele frequency was higher in most Amerindian populations (0.17 in Yaquis, 0.16 in Mazahuas, 0.16 in Mayans, and 0.20 in Triquis) than in Asians, African Americans, and Caucasians. The Pro12Ala and Ala12Ala (X12Ala) genotypes were significantly associated with greater BMI in Mexican Mestizos and in two Amerindian groups. X12Ala individuals had a higher risk of overweight or obesity than noncarriers in Mestizos (OR = 3.67; 95% CI, 1.42-9.48; p = 0.007) and in Yaquis plus Mazahuas (OR = 3.21; 95% CI, 1.27-8.11; p = 0.013). Our results provide further support of the association between the PPARG2 Ala12 allele and risk of overweight or obesity in Mestizos and two Amerindian populations from Mexico.
Asunto(s)
Variación Genética/genética , Genética de Población/métodos , Genotipo , Indígenas Norteamericanos/genética , PPAR gamma/genética , Adulto , Índice de Masa Corporal , Humanos , México , Persona de Mediana Edad , Obesidad/genéticaRESUMEN
To determine the association of in vivo concentrations of insulin, obesity, and gender with lipoprotein(a) [Lp(a)] levels, we used a cross-sectional population-based survey of a multistage random sample of the Mexico City adult population. We studied 423 normoglycemic, normotensive subjects from an original sample of 825, comprised of 239 men and 189 women with a mean age of 38.6 years (range, 17 to 90). All subjects were divided into 8 groups according to body mass index, fasting insulin, and gender. Lp(a) concentrations (mg/dL) were similar in obese women with and without high insulin levels (19.9 v 18.6), but hyperinsulinemic obese men had significantly lower Lp(a) levels than normoinsulinemic obese men (7.9 v 29.4). In addition, the proportion of obese men with Lp(a) concentrations of > or = 30 mg/dL was significantly higher in the normoinsulinemic than in the hyperinsulinemic (29.2% v 0.0%). The frequency distribution of Lp(a) levels was shifted to a lower range in hyperinsulinemic men compared with normoinsulinemic men. Our results show that in men, hyperinsulinemic obesity is associated with low Lp(a) levels, while obesity with normoinsulinemia is related to increased Lp(a) concentration. These observations were not found in women. These findings may explain the conflicting results reported by several studies.
Asunto(s)
Hiperinsulinismo/sangre , Hiperinsulinismo/complicaciones , Lipoproteína(a)/sangre , Obesidad/sangre , Obesidad/complicaciones , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Índice de Masa Corporal , Estudios Transversales , Femenino , Humanos , Insulina/sangre , Masculino , México , Persona de Mediana Edad , Análisis de Regresión , Caracteres SexualesRESUMEN
Insulin resistance has been implicated in the pathogenesis of essential hypertension. Studies from other countries discovered insulin resistance; in people with essential hypertension in was also associated with obesity, however, insulin resistance was found in lean people too. In obesity, insulin resistance occurs secondarily to many physiopathological states and circulating factors which adversely affects insulin action. The metabolic abnormality in this action was mainly found in relation to abdominal fat; in other cases, insulin resistance was found to be inherited. Hyperinsulinaemia can actually increase blood pressure and is associated with venous and arterial thrombosis and it also rises lipid levels. It is interesting too that insulin resistance and hyperinsulinaemia are associated with impaired fibrinolysis through high levels of fibrinogen and plasminogen activator inhibitor of endothelial type and in identifying individuals prone to myocardial infarction. Some antihypertensive drugs like beta-blockers, methyl-dopa and diuretics increase insulin resistance, while angiotensin converting enzyme-inhibitors have not shown any adverse metabolic affects. Alfa-1-blocker were beneficial and alfa-2-agonists were neutral, whereas calcium channel-antagonists are still in controversy. Treatment should be designed to improve the metabolic state; physical exercise, a diet rich in fruit, vegetable and rott vegetables, the reduction of abdominal fat and, finally, the use of antihypertensive drugs which decrease insulin resistance would be expected to reverse hyperinsulinaemia. Biguanides like metformin have also been found to reduce insulin resistance.
Asunto(s)
Enfermedad Coronaria/etiología , Hipertensión/etiología , Resistencia a la Insulina , Terapia Combinada , Enfermedad Coronaria/metabolismo , Humanos , Hiperinsulinismo/complicaciones , Hiperinsulinismo/metabolismo , Hipertensión/metabolismo , Hipertensión/terapia , Obesidad/complicaciones , Obesidad/metabolismoRESUMEN
Prospective study performed at the General Hospital, National Medical Center, XXI Century, Endocrinology Ward, Mexico-City, to compare the diagnostic sensitivity in Cushing's disease of the oral high doses (8 mg) dexametazone suppression test in single doses with nocturnal administration (DXM-N) and the classic doses of two days (DXM-C). Fourteen patients with hypercortisolism were studied; on thirteen the hypophyseal origin was surgical confirmed. Sensitivity of high doses of oral dexametazone test was proved by using serial samples of serum cortisol; the Fisher test was used for analysis of the suppression of serum cortisol after the test was done.