title: Vitamin D-binding protein and free vitamin D concentrations in acromegaly.
abstract: Free 25-hydroxyvitamin D [25(OH)D] is suggested to be important in the determination of vitamin D deficiency, since vitamin D-binding protein (VDBP) may affect total 25(OH)D levels. There are no data about free 25(OH)D concentrations in acromegaly. We aimed to investigate serum VDBP and total and free 25(OH)D levels in patients with acromegaly in comparison with control subjects. We recruited 54 patients with acromegaly and 32 control subjects who were similar according to age, gender, and body mass index. Serum VDBP levels were found to be increased in patients with acromegaly compared to control subjects [90.35 (72.45-111.10) vs. 69.52 (63.89-80.13) mg/l, p = 0.001]. There was statistically no significant difference in serum total 25(OH)D levels between the patients with acromegaly and control subjects [18.63 (13.35-27.73) vs. 22.51 (19.20-28.96) ng/ml, p = 0.05]. Free 25(OH)D levels were significantly decreased in patients with acromegaly compared to control subjects [14.55 (10.45-21.45) vs. 17.75 (15.30-23.75) pg/ml, p = 0.03]. Free 25(OH)D levels correlated positively with total 25(OH)D (p = 0.0001) and HDL cholesterol (p = 0.04) and negatively with fasting blood glucose (p = 0.04). Our findings indicate that VDBP is increased and free 25(OH)D is decreased in acromegaly, while there is no significant alteration in total 25(OH)D.
authors.affiliation: Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Besevler, 06500, Ankara, Turkey.
authors.forename: Alev Eroglu
authors.initials: AE
authors.lastname: Altinova
authors.affiliation: Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Besevler, 06500, Ankara, Turkey. cozkan34@hotmail.com.
authors.forename: Cigdem
authors.initials: C
authors.lastname: Ozkan
authors.affiliation: Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Besevler, 06500, Ankara, Turkey.
authors.forename: Mujde
authors.initials: M
authors.lastname: Akturk
authors.affiliation: Department of Biochemistry, Gazi University Faculty of Medicine, Ankara, Turkey.
authors.forename: Ozlem
authors.initials: O
authors.lastname: Gulbahar
authors.affiliation: Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Besevler, 06500, Ankara, Turkey.
authors.forename: Muhittin
authors.initials: M
authors.lastname: Yalcin
authors.affiliation: Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Besevler, 06500, Ankara, Turkey.
authors.forename: Nuri
authors.initials: N
authors.lastname: Cakir
authors.affiliation: Department of Endocrinology and Metabolism, Gazi University Faculty of Medicine, Besevler, 06500, Ankara, Turkey.
authors.forename: Fusun Balos
authors.initials: FB
authors.lastname: Toruner
mesh_terms: D000172:Acromegaly / Q000097:blood*; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014807:Vitamin D / Q000097:blood*; D014809:Vitamin D-Binding Protein / Q000097:blood*
chemical_list: D014809:Vitamin D-Binding Protein; D014807:Vitamin D
keywords: Acromegaly; Free vitamin D; Total vitamin D; Vitamin D-binding protein