Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: December 2, 2002
Publication Date: March 14, 2003
Citation: Hunt, C.D., Idso, J.P. 2003. Hyperinsulinemia in rats during dietary vitamin D (VitD) and boron deprivation is ameliorated, but not corrected, by improved VitD status [abstract]. The Federation of American Societies for Experimental Biology Journal. 17:A707. Technical Abstract: Our laboratory demonstrated earlier that VITD-deprived, magnesium (Mg)-adequate rats exhibit hyperinsulinemia when deprived of dietary boron (B) (151+/-103 vs 32+/-20 pmol/L plasma; p<0.002; Magn Trace Elem, 10:374, 1991-1992). The role of dietary VITD and Mg in this abnormality was pursued in a 2x2x2 factorially-arranged experiment with Sprague-Dawley male rats (12/treatment) fed a VITD- and B-low (~0.1 mg B/kg) basal diet supplemented with B (as orthoboric acid) at 0 or 2 mg/kg, Mg (as Mg acetate) at 100 (100Mg) or 400 (400Mg) mg/kg, and VITD (as vitamin D**3; 1000 IU/kg) beginning on day 0 (VITD0) or 17 (VITD17). On d 35, boron deprivation increased fasting plasma insulin (p<0.03) regardless of VITD or Mg status (data log transformed; means and +/-1SD; VITD0: 100Mg, 42.1 (31.5, 56.3) vs 37.0 (31.8, 43.0); 400Mg:47.0(35.2,62.8)vs 37.4(32.8,42.5); VITD17: 100Mg, 43.4 (34.8, 54.1) vs 40.9 (30.0, 55.7); 400Mg: 59.2 (43.4, 80.7) vs 53.5 (35.5, 80.7) pmol/L plasma) but to a lesser extent observed earlier with extended VITD deprivation. Impaired VITD status (17 d of VITD repletion) also elevated plasma insulin concentrations (p<0.004). Boron deprivation may increase insulin resistance because that treatment did not affect plasma glucose concentrations. The findings indicate that a diet limited in fruits and vegetables (the main sources of dietary boron) may alter insulin metabolism, especially when dietary vitamin D is severely limited.