THE EFFECT OF BORON ON PLASMA TESTOSTERONE AND PLASMA-LIPIDS IN RATS

Recent studies have indicated that dietary boron can affect the concen tration of steroid hormones in vivo. It has been suggested that the in teraction between boron and steroid hormone metabolism is mediated by the hydroxylation process that steroids need to become biologically ac tive. The increase in the concentration of some steroid hormones may i mpact favourably on cardiovascular and bone diseases. The following ex periment was performed to determine the specificity of the effect of b oron on steroid hormones and to determine the subsequent impact on pla sma lipids in rats over a 4 week study period. Upon addition of boron (as boric acid) to the drinking water to provide 2 mg boron/rat/day, t here was no change in body or testicular weight between the control an d treatment groups. The addition of boric acid to the drinking water r esulted in significant elevations in the plasma 1,25-dihydroxyvitamin D concentration at week 2 (P<0.01) and the plasma testosterone concent ration at week 4 (P<0.05) relative to the control group. After 2 weeks , there was a significant decrease in the plasma triacylglycerol (P<0. 05) and total HDL-cholesterol concentrations (P<0.05) in rats fed bori c acid relative to their counterparts in the control group. However, a t week 4 only HDL(3)-cholesterol was significantly lower (P<0.002). Th e potentially favourable effects of increasing the concentrations of v itamin D, testosterone and oestrogen (as shown in other studies) on ch ronic diseases need to be balanced against the reduction in HDL(3)-cho lesterol. Copyright (C) 1997 Elsevier Science Inc.