Body-fat distribution and responsiveness of the pituitary-adrenal axis to corticotropin-releasing-hormone stimulation in sedentary and exercising women.
Excess upper-body (android) fat is considered an health hazard. Exercise training is known to have the potential to modify body composition and to induce a preferential loss of abdominal fat. We studied and compared the composition of whole body and major body regions using dual-energy X-ray absorptiometry (DEXA) in 21 exercising (3-4 hours of intense physical activity/day) and 21 sedentary eumenorrhoic women of similar ages, body mass index (BMI), waist-to-hip ratio (WHR) and age of menarche. In a small number of women in each group (6 out of 21), the ACTH and cortisol response to CRH test and the 24-h urinary cortisol excretion was evaluated. Exercising women had 10% higher total and leg lean mass (p<0.05), and 38% lower total fat mass (p<0.01) than sedentary women. Furthermore, the proportion of android fat was 22% lower in exercising than sedentary women (p<0.01), while the proportion of lower-body (gynoid fat) was unchanged. BMI and WHR were not different between the two groups, while the android/gynoid fat ratios were 16% lower in exercising than in sedentary women (p<0.01). In the exercising women, ACTH and cortisol plasma levels, as well as the 24-h urinary cortisol excretion, were significantly (p<0.01) higher than in the sedentary women studied. In these subjects, a direct relationship between the peak delta percentage increases of ACTH and cortisol after the CRH test and the proportion of android fat was found (r=0.60, p<0.05 and r=0.69, p<0.02, respectively). These results demonstrate that in women who practise intense exercise there are significant differences in body fat distribution in comparison to sedentary women, with a marked less amount of android fat, and suggest that this difference may be related to a reduced response of the pituitary-adrenal axis to CRH.
Fabbri
A
A
Cattedra di Andrologia, Dipartimento Fisiopatologia Medica, Università di Roma La Sapienza, Italy. a.fabbri@caspur.it
Giannini
D
D
Aversa
A
A
De Martino
M U
MU
Fabbrini
E
E
Franceschi
F
F
Moretti
C
C
Frajese
G
G
Isidori
A
A
D015502:Absorptiometry, Photon; D000273:Adipose Tissue; D000311:Adrenal Glands / Q000187:drug effects / Q000502:physiology*; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000367:Age Factors; D001823:Body Composition; D001824:Body Constitution; D015992:Body Mass Index; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D015444:Exercise; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000652:urine; D007700:Kinetics; D008572:Menarche; D010902:Pituitary Gland / Q000187:drug effects / Q000502:physiology*
D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006854:Hydrocortisone