title: Urinary growth hormone (GH), insulin-like growth factor I (IGF-I), and IGF-binding protein-3 measurements in the diagnosis of adult GH deficiency.
abstract: The diagnosis of GH deficiency (GHD) in the elderly is based at present on the peak GH concentration during a stimulation test. We have now evaluated the performance of urinary GH (uGH), urinary insulin-like growth factor I (uIGF-I), and urinary IGF-binding protein-3 (uIGFBP-3) in the diagnosis of GHD in this group. Twenty GHD elderly patients with a history of pituitary disease and a peak GH response to arginine stimulation of less than 3 ng/mL (15 men and 5 women; age, 61.1-83.4 yr) and 19 controls (12 men and 7 women; age, 60.8-87.5 yr) were studied. GH secretion was assessed by 24-h profile and expressed as the area under the curve (AUCGH). Serum (s) IGF-I and sIGFBP-3 were measured in a single morning, fasted sample. Urinary GH, uIGF-I, and uIGFBP-3 were measured in a 24-h urine sample collected over the same interval as the GH profile, and results were expressed as total amount excreted in 24 h (tuGH24, nanograms; tuIGF-I24, nanograms; tuIGFBP-3(24), micrograms). Data are presented as the mean +/- SD, except for AUCGH, tuGH24, and tuIGFBP-3(24), which are presented as the geometric mean (-1, +1 tolerance factor). AUCGH, sIGF-I, and sIGFBP-3 were significantly lower in GHD subjects than in controls. Total uGH24 was lower in GHD subjects, but tuIGF-I24 and tuIGFBP-3(24) excretion were not different in the two groups. AUCGH provided the best separation between GHD and control subjects, whereas there was substantial overlap for sIGF-I, sIGFBP-3, and tuGH24. In both groups sIGF-I was correlated to sIGFBP-3 (GHD, r = 0.75; controls, r = 0.65; both P < 0.01), whereas tuIGF-I24 was not correlated to tuIGFBP-3(24) in either group. Moreover, tuIGF-I24 and tuIGFBP-3(24) were not related to their respective serum concentrations in either group. Total uGH24 was correlated with AUCGH only in controls (r = 0.54; P < 0.05). These data demonstrate that urinary GH and urinary and serum IGF-I and IGFBP-3 are not suitable diagnostic markers for GHD in elderly subjects.
authors.affiliation: Endocrine Sciences Research Group, University of Manchester, United Kingdom.
authors.forename: M S
authors.initials: MS
authors.lastname: Gill
authors.forename: A A
authors.initials: AA
authors.lastname: Toogood
authors.forename: P A
authors.initials: PA
authors.lastname: O'Neill
authors.forename: M O
authors.initials: MO
authors.lastname: Thorner
authors.forename: S M
authors.initials: SM
authors.lastname: Shalet
authors.forename: P E
authors.initials: PE
authors.lastname: Clayton
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D019382:Human Growth Hormone / Q000172:deficiency / Q000502:physiology* / Q000652:urine; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood / Q000652:urine*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000652:urine; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012727:Sex Characteristics
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I