Octreotide, a somatostatin analog, reduces insulin secretion and increases renal Na+ excretion in lean essential hypertensive patients.
The influence of insulin on renal Na+ excretion is still subject to debate. In order to evaluate the effect of insulin suppression on Na+ excretion, 20 never-treated essential hypertensive men and 8 normotensive men were studied. All subjects had a body mass index < 27 kg/m2. Both the glucose and the lipid metabolisms were normal. After 2 weeks under normal NaCl intake (120 mEq NaCl daily), either octreotide, a somatostatin analog, or vehicle were infused in a forearm vein during acute volume expansion (0.30 mL/kg/min isotonic saline given intravenously over a period of 30 min). A double-blind randomized cross-over design was followed, and each subject was given both infusions at a 1 week interval. Blood and urine samples were taken at times--60, 0, 30, 60, 90, 120, 180, 240, and 300 min. Our data showed that octreotide significantly lowered insulin levels in both hypertensives (from 12.2 +/- 2.4 microU/mL at time 0 to undetectable values at time 30 and 60 min) and normotensives (from 11.5 +/- 2.8 microU/mL at time 0, to undetectable values at time 30 and 60 min). Compared to saline infusion alone, octreotide significantly increased Na+ excretion in both hypertensives and normotensives (saline + octreotide v saline alone = P < .05 at time 60 and 90 min). In conclusion, octreotide enhanced the natriuretic response to intravenous Na+ load in both hypertensives and normotensives. The increase in urinary Na+ was accompanied by a significant decrease in plasma insulin levels.
Ferri
C
C
University of Rome La Sapienza, Institute of I Clinica Medica, Andrea Cesalpino Foundation, Italy.
De Mattia
G
G
Bellini
C
C
Laurenti
O
O
Bravi
C
C
Baldoncini
R
R
Bonavita
M S
MS
Santucci
A
A
Balsano
F
F
D000328:Adult; D001835:Body Weight; D004311:Double-Blind Method; D006801:Humans; D006973:Hypertension / Q000378:metabolism* / Q000473:pathology / Q000652:urine; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000494:pharmacology*; D012016:Reference Values; D012964:Sodium / Q000652:urine*
D007328:Insulin; D012964:Sodium; D015282:Octreotide