title: Interactions between vitamin D and IGF-I: from physiology to clinical practice.
abstract: The interplay between vitamin D and IGF-I is complex and occurs at both endocrine and paracrine/autocrine levels. Vitamin D has been shown to increase circulating IGF-I and IGFBP-3, with the consistent finding of a positive correlation between vitamin D and IGF-I serum values in population-based cohorts of healthy subjects. The modulation of IGF-I and IGFBP-3 concentrations by vitamin D may impact recombinant human (rh) GH dosing for the treatment of GHD. It might also underlie some of the extra-skeletal beneficial effects ascribed to vitamin D. On the other hand, IGF-I stimulates renal production of 1,25-dihydroxyvitamin D, which increases calcium and phosphate availability in the body and suppresses PTH secretion. This effect is responsible for an altered calcium-phosphate balance in uncontrolled acromegaly and might also account for the improvement in bone metabolism associated with rhGH treatment in patients with GHD. Data on the paracrine/autocrine vitamin D-IGF-I interactions are abundant, but mostly not linked to one another. As a result, it is not possible to draw a comprehensive picture of the physiological and/or pathological interrelations between vitamin D, IGF-I and IGF-binding proteins (IGFBP) in different tissues. A potential role of vitamin D action is related to its association with carcinogenesis, a paradigm being breast cancer. Current evidence indicates that, in breast tumours, vitamin D modulates the IGF-I/IGFBP ratio to decrease proliferation and increase apoptosis.
authors.affiliation: Division of Endocrinology, Department of Medicine, New York University School of Medicine, New York, NY, USA.
authors.forename: Pietro
authors.initials: P
authors.lastname: Ameri
authors.forename: Andrea
authors.initials: A
authors.lastname: Giusti
authors.forename: Mara
authors.initials: M
authors.lastname: Boschetti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Murialdo
authors.forename: Francesco
authors.initials: F
authors.lastname: Minuto
authors.forename: Diego
authors.initials: D
authors.lastname: Ferone
mesh_terms: D019898:Autocrine Communication / Q000502:physiology*; D019382:Human Growth Hormone / Q000172:deficiency / Q000627:therapeutic use; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D019899:Paracrine Communication / Q000502:physiology*; D014807:Vitamin D / Q000097:blood / Q000378:metabolism / Q000502:physiology*
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D019382:Human Growth Hormone; D014807:Vitamin D; D007334:Insulin-Like Growth Factor I