TY - JOUR
T1 - Unaltered ratio of circulating levels of growth hormone/GH isoforms in adults with Prader-Willi syndrome after GHRH plus arginine administration
AU - Rigamonti, A. E.
AU - Grugni, G.
AU - Marazzi, N.
AU - Bini, S.
AU - Bidlingmaier, M.
AU - Sartorio, A.
PY - 2015/8/1
Y1 - 2015/8/1
N2 - Human growth hormone (GH) is a heterogeneous protein hormone consisting of several isoforms, the most abundant being 22kDa- and 20kDa-GH. The availability of analytical methods to measure these GH isoforms might represent a valuable diagnostic tool to investigate GH hyposecretory states, including Prader-Willi syndrome (PWS), one of the most common causes of syndromic obesity. The aim of the present study was to measure circulating levels of 22kDa- and 20kDa-GH in PWS adults (n=14; M/F: 5/9; genotype DEL15/UPD15: 12/2; age: 19.0±3.7years; BMI: 29.9±8.7kg/m2) after combined GH releasing hormone (GHRH) plus arginine (ARG) administration. The results were analysed subdividing the study population in obese vs. nonobese (6/8) and GH deficient vs. nonGH deficient (GHD) (6/8) subjects, according to appropriate BMI-related diagnostic cut-off limits of GH peak response to the provocative test. Circulating levels of 22kDa-GH were measured by a chemiluminescent method based on a detection monoclonal antibody targeting an epitope in the loop connecting helix 1 and 2 of GH, which is missing in 20kDa-GH; the 20kDa-GH was measured using a time resolved fluorescence assay based on two monoclonal antibodies with no cross-reactivity to 22-kDa GH.GHRH plus ARG significantly stimulated the secretions of 22. kDa- and 20. kDa-GH in nonobese (at 30, 45, 60 and 90. min and at 45, 60, 90 and 120. min vs. 0. min, p.
AB - Human growth hormone (GH) is a heterogeneous protein hormone consisting of several isoforms, the most abundant being 22kDa- and 20kDa-GH. The availability of analytical methods to measure these GH isoforms might represent a valuable diagnostic tool to investigate GH hyposecretory states, including Prader-Willi syndrome (PWS), one of the most common causes of syndromic obesity. The aim of the present study was to measure circulating levels of 22kDa- and 20kDa-GH in PWS adults (n=14; M/F: 5/9; genotype DEL15/UPD15: 12/2; age: 19.0±3.7years; BMI: 29.9±8.7kg/m2) after combined GH releasing hormone (GHRH) plus arginine (ARG) administration. The results were analysed subdividing the study population in obese vs. nonobese (6/8) and GH deficient vs. nonGH deficient (GHD) (6/8) subjects, according to appropriate BMI-related diagnostic cut-off limits of GH peak response to the provocative test. Circulating levels of 22kDa-GH were measured by a chemiluminescent method based on a detection monoclonal antibody targeting an epitope in the loop connecting helix 1 and 2 of GH, which is missing in 20kDa-GH; the 20kDa-GH was measured using a time resolved fluorescence assay based on two monoclonal antibodies with no cross-reactivity to 22-kDa GH.GHRH plus ARG significantly stimulated the secretions of 22. kDa- and 20. kDa-GH in nonobese (at 30, 45, 60 and 90. min and at 45, 60, 90 and 120. min vs. 0. min, p.
KW - GH deficiency
KW - GH isoforms
KW - GHRH plus arginine
KW - Obesity
KW - Prader-Willi syndrome
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U2 - 10.1016/j.ghir.2015.06.002
DO - 10.1016/j.ghir.2015.06.002
M3 - Article
C2 - 26059749
AN - SCOPUS:84937517271
VL - 25
SP - 168
EP - 173
JO - Endocrinology and Metabolism, Supplement
JF - Endocrinology and Metabolism, Supplement
SN - 1096-6374
IS - 4
ER -