title: Greater secretion of growth hormone in black than in white men: possible factor in greater bone mineral density--a clinical research center study.
abstract: To determine why blacks have a higher bone mineral density (BMD) and lower incidence of osteoporosis and fractures than whites, we investigated whether the secretion of GH is higher in black than in white men. Measurements of GH were obtained at 20-min intervals over 24 h and analyzed by deconvolution. BMD was determined by dual energy x-ray absorptiometry in 16 normal black and 17 normal white men, aged 20-40 yr. The 24-h integrated GH concentration 942 +/- 174 vs. 602 +/- 104 micrograms/L; P = 0.0495) and GH secretory burst amplitude (0.499 +/- 0.163 vs. 0.169 +/- 0.027 micrograms/L.min; P = 0.0482) were higher in black than in white men. GH burst frequency, half-duration, mass, and half-life were not different in the 2 groups. The serum 17 beta-estradiol level (162 +/- 12 vs. 108 +/- 11 pmol/L; P = 0.0011) was higher, and the serum insulin-like growth factor-binding protein 3 level (2.2 +/- 0.1 vs. 2.8 +/- 0.1 microgram/mL; P = 0.0001) was lower in black than in white men. BMD values for total body (1.22 +/- 0.02 vs. 1.14 +/- 0.02 g/cm2; P = 0.0041), forearm (0.69 +/- 0.01 vs. 0.66 +/- 0.01 g/cm2; P = 0.0211), trochanter (0.91 +/- 0.03 vs. 0.77 +/- 0.03 g/cm2; P = 0.0003), and femoral neck (1.08 +/- 0.03 vs. 0.93 +/- 0.03 g/cm2; P = 0.0007) were higher in black than in white men. Thus, serum 17 beta-estradiol level, GH secretion, and BMD values for the total body, forearm, trochanter, and femoral neck are greater in black than in white men. As estrogen is known to increase GH secretion and GH to increase bone mass, increases in circulating 17 beta-estradiol may contribute to the higher GH secretion and bone mass in black men.
authors.affiliation: Department of Pediatrics, Medical University of South Carolina 29425, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Wright
authors.forename: J
authors.initials: J
authors.lastname: Renault
authors.forename: S
authors.initials: S
authors.lastname: Willi
authors.forename: J D
authors.initials: JD
authors.lastname: Veldhuis
authors.forename: J P
authors.initials: JP
authors.lastname: Pandey
authors.forename: L
authors.initials: L
authors.lastname: Gordon
authors.forename: L L
authors.initials: LL
authors.lastname: Key
authors.forename: N H
authors.initials: NH
authors.lastname: Bell
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000328:Adult; D044383:Black People; D001823:Body Composition; D015519:Bone Density; D002352:Carrier Proteins / Q000097:blood; D002940:Circadian Rhythm; D004958:Estradiol / Q000097:blood; D050723:Fractures, Bone / Q000453:epidemiology; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006207:Half-Life; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D008297:Male; D010024:Osteoporosis / Q000453:epidemiology; D012044:Regression Analysis; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013739:Testosterone / Q000097:blood; D044465:White People; D005719:gamma-Globulins / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D012738:Sex Hormone-Binding Globulin; D005719:gamma-Globulins; D013739:Testosterone; D004958:Estradiol; D013006:Growth Hormone