Efeitos da ingestão oral de glicose sobre a excreção urinaria de eletrolitos e acidos em pacientes com hipertensão arterial essencial

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

This study was conducted on 18 normotesive healthy subjetcs (NT) and on 17 essentlally hypertenslve (HT) patlents wlth dlastolic blood pressure above 95 mmHg, aged between twenty and forty five years old. Additional criteria for Inclusion In the study were 90 to 110% o, Ideal body welght according to the Metropolltan Llfe Insurance Tables, and a normal gfucose tolerance test. No patient or control was recelving any medicatlon. The studies wer.e performed in the morning, starting at 7:00 AM, after a overnlght fast, until 1 :00 PM. Imedlately after to empty his bladder, each subject ingested 20 ml of tap water/kg body weight and hourly volume similar to the diuresis. After a 2 h control period, an oral glucose tolerance test wlth a 100g glucose load was performed (GTT) on 15 normotensive (NG)- and on 15 hypertensive (HG). The control groups, 15 normotensive (NH) and 12 hypertensive (HH), received only tap water. Blood pressure was measured at 30 min Intervals. Urine aliquots were pooled at 1 hour Intervals and bfood samples were collected at 8:00, 9:30; 10:00; 10:30; 11 :00; 12:00 AM and 1 :00 PM. After oral gfucose ingestion (IOG), Insulin levels were signiflcantly higher In five of the 15 patients (hyperlnsullnemic hypertensive HHI) than in normotensive and in normoinsulinemic hypertensive (HNI). The maximum plasma glucose. at 60 min after IOG were slgnlflcantly hlgher In the HNI subgroup. There is no significant dirrerence between groups or significant changes in plasma levels of Na+. K+ and creatinine; In creatinine clearances and glomerular fIItratlon rate of Na + and K+. except In HHI. In this subgroup. a translent but significant decrease In creatlnlne clearance occurred at 60 min after 10G. followed by a significant fali of the glomerular filtration rate of K+ and Na+. After water load. it was observed a significant hlgher urinary sodium excretion (UNaV) In both hypertenslve groups. HH and HG, than in normotensives. On the other hand, a glucose ingestion induced a significant fall In UNaV and In fractlonal sodium excretion. similar in NG and HG. and In HHI and HNI. Also, a similar decrease In plasma K+ levels, and a similar antlkalluresis were observed in NG and HG groups, but a higher antlkalluresls was obtained In HHI subgroups. No significant differences were found between groups, neither between control and experimental periods for NH4 + urinaryexcretion. The urinary aeidity tritrable exeretion decreased slow and eon tinously in the control groups (NH and HH) and increased more in NG 1han In HG groups a1 60 min after glucose loading Ingestion. No significant correlations were found between plasma Insulin or glucose and frational sodium or potassium excretion. Since the oral glucose load has no effect on glomerular filtration rate, except in HHI. the antinatriuresis seem to be due an increase in tubular lon reabsorptlon. The tubular sltes involved In thls insulln actlons m ay be the proxlmal nephron segments and the tlck ascend Ing 11mb of Henle. The results of thls protocol may suggest a resistance in renal tissues to insulin actlon on natriuresis, but not to the effects on kalluresis.

ASSUNTO(S)

clinica medica hipertensão

ACESSO AO ARTIGO

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