Effects of chronic fructose overload on renal dopaminergic system: alteration of urinary L-dopa/dopamine index correlates to hypertension and precedes kidney structural damage

RUKAVINA MIKUSIC NL; KOUYOUMDZIAN NM; DEL MAURO J; CAO G; TRIDA VA; GIRONACCI MM; PUYÓ AM; TOBLLI JE; FERNÁNDEZ BE; CHOI MR

JOURNAL OF NUTRITIONAL BIOCHEMISTRY

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2018 vol. 51 p. 47 - 55

0955-2863

Insulin resistanceinduced by a high fructose diet has been associated to hypertension and renaldamage. The aim of this work was to assess alterations in the urinaryL-dopa/dopamine ratio over three time periods in rats with insulin resistanceinduced by fructose overload and its correlation with blood pressure levels andthe presence of microalbuminuria and reduced nephrin expression as markers ofrenal structural damage. Male Sprague-Dawley rats were randomly divided in sixgroups: control (C) (C4, C8 and C12) with tap water to drink; andfructose-overloaded (FO) rats, (FO4, FO8 and FO12), with a fructose solution(10% w/v) to drink; for 4, 8 and 12 weeks. A significant increase of theurinary L-dopa/dopamine ratio was found in FO rats since week 4, whichpositively correlated to the development of hypertension and preceded in timethe onset of microalbuminuria and reduced nephrin expression observed on week12 of treatment. The alteration of this ratio was associated to an impairmentof the renal dopaminergic system, evidenced by a reduction in renal dopamine transportersand dopamine D1 receptor expression, leading to an over-expression andover-activation of the enzyme Na+, K+- ATPase with sodiumretention. In conclusion, urinary L-dopa/dopamine ratio alteration in rats withfructose overload positively correlated to the development of hypertension andpreceded in time the onset of renal structural damage. This is the first studyto propose the use of the urinary L-dopa/dopamine index as marker of renaldysfunction that temporarily precedes kidney structural damage induced byfructose overload.