Renehan AG, Frystyk J, Howell A, O'dwyer ST, Shalet SM, Flyvbjerg A. The effects of sex steroid replacement therapy on an expanded panel of IGF-related peptides.
Growth Horm IGF Res 2007;
17:210-219. [PMID:
17360217 DOI:
10.1016/j.ghir.2007.01.017]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Revised: 01/08/2007] [Accepted: 01/23/2007] [Indexed: 11/24/2022]
Abstract
BACKGROUND
Oral estrogen alone (EA) decreases concentrations of total IGF-I while increasing IGFBP-1, but data on other IGF-related peptides are inconsistent and/or sparse. Combined oral estrogen and progestin (EP) may have differential effects on IGF-related peptides dependent on its progestin-associated androgenic activity. The aim of this study was to clarify these relationships, as circulating IGF-related peptides are potential surrogates of predisposition to common chronic diseases.
DESIGN
Using an open-labelled cross-sectional design within a bowel cancer screening trial (aged 55-64 years), we determined total IGF-I, IGF-II, IGFBP-2 and IGFBP-3 in fasted serum from 210 healthy women and free IGF-I (by ultrafiltration), insulin, IGFBP-1 and IGFBP-1:IGF-I binary complex in a selected subset of 92 women. Unadjusted and adjusted (using generalized linear models) means were compared.
RESULTS
Among EA users, mean concentrations for total IGF-I (adjusted P=0.004) and free IGF-I (P<0.001) were reduced, whereas mean concentrations of IGFBP-1 (P=0.001) and binary complex (P=0.01) were increased compared with non-users. Taken as a whole group, EP use was not associated with differences in concentrations of IGF-related peptides, but on sub-group analyses, mean concentrations associated with the use of progestins with reduced androgenic activity reflected the use of EA. By contrast, mean IGFBP-2 concentrations were significantly reduced among both EA (P=0.008) and EP (P=0.002) users, irrespective of androgenic activity. Neither EA nor EP influenced mean concentrations of IGF-II, insulin and IGFBP-3.
CONCLUSIONS
The uses of oral sex steroid replacements are associated with significant changes in several IGF-related analytes in a preparation-specific manner, suggesting different regulatory mechanisms. However, the directions of these changes do not fit simple correlative models of predisposition to common diseases.
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