sábado, 7 de agosto de 2010

Adrenal e distribuição de gordura corporal

Um artigo recente estudou a relação entre distribuição de gordura corporal e diversos aspectos funcionais do eixo adrenal, com testes dinâmicos e conceitos complexos e bem interessantes.
 
Hypothalamic-Pituitary-Adrenal (HPA) Axis Functioning in Relation to Body Fat Distribution
Clinical Endocrinology , 2010-06-01

Abstract

Objective To relate hypothalamic–pituitary–adrenal (HPA) axis functioning and HPA feedback functioning to body fat distribution in normal weight to obese subjects.
Patients 91 men and 103 women [age 18–45 years, BMI 19–35 kg/m2, waist-to-hip ratio (WHR) 0·6–1·1]
Measurements Anthropometry, body composition using hydrodensitometry and deuterium dilution method, cortisol variability by measuring 5-h cortisol concentrations, HPA axis feedback functioning using a dexamethasone suppression test, and HPA axis functioning under a challenged condition consisting of a standardized high-intensity test with ingestion of 4 mg dexamethasone.
Results In men, an inverse relationship was observed between 5-h cortisol exposure (nmol/ml) and fat mass index (FMI) (kg/m2) (r = −0·55, P < 0·001). In women, relationships were observed between 5-h cortisol exposure (nmol/ml.min) and WHR (r = −0·49, P < 0·001), maximal workload (r = 0·32, P < 0·001) as well as oral contraceptive use (r = 0·38, P < 0·001). Similarly, in men, an inverse relationship was observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and FMI (r = −0·53, P < 0·001). In women, relationships were observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and WHR (r = −0·43, P < 0·001), maximal workload (r = 0·30, P < 0·001) as well as oral contraceptive use (r = 0·43, P < 0·001) in women. Moreover, an inverse relationship was observed between HPA axis functioning in a challenged condition expressed as percentage increase of cortisol concentrations after standardized high-intensity test with ingestion of 4 mg dexamethasone (%) and waist circumference (r = −0·21, P < 0·10) in men and WHR (r = −0·21, P < 0·05) in women. In men, strong positive relationships were observed between FMI and waist circumference (r = 0·85, P < 0·001), as well as waist-to-hip ratio (r = 0·70, P < 0·001).
Conclusion Disturbance of HPA axis functioning under basal and challenged conditions is related to visceral fat accumulation.

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