Circulating dopamine and C-peptide levels in fasting nondiabetic hypertensive patients: the Graz Endocrine Causes of Hypertension study.
OBJECTIVE
Accumulating evidence supports a potential role for dopamine in the regulation of insulin secretion. We examined the association between circulating dopamine and C-peptide concentrations using data from the Graz Endocrine Causes of Hypertension (GECOH) study.


METHODS
After 12 h of fasting, we measured plasma dopamine and serum C-peptide levels and established determining factors of insulin secretion in 201 nondiabetic hypertensive patients (mean age 48.1 ± 16.0 years; 61.7% women).


RESULTS
Mean dopamine and C-peptide concentration were 33.4 ± 38.6 pg/mL and 3.1 ± 2.7 ng/mL, respectively. A strong and inverse correlation was observed between dopamine and C-peptide levels (r = -0.423, P < 0.001). There was no significant relationship between C-peptide, plasma epinephrine, and norepinephrine. C-peptide levels decreased steadily and significantly from tertile 1 of dopamine (3.6 ng/mL [95% CI 2.9-4.1]) to tertile 3 (1.6 ng/mL [1.5-2.7], P < 0.001) after multivariate adjustment.


CONCLUSIONS
The inverse association between dopamine and C-peptide highlights the need to evaluate whether dopamine could be effective for modulating endocrine pancreatic function.
Department of Internal Medicine, Division of Cardiology, Medical University of Graz, Graz, Austria. andreas.tomaschitz@gmx.at
Andreas
A
Tomaschitz
Eberhard
E
Ritz
Katharina
K
Kienreich
Burkert
B
Pieske
Winfried
W
März
Bernhard O
BO
Boehm
Christiane
C
Drechsler
Andreas
A
Meinitzer
Stefan
S
Pilz
D000328:Adult; D002096:C-Peptide / Q000097:blood*; D004298:Dopamine / Q000097:blood*; D005215:Fasting / Q000097:blood*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood*; D008297:Male; D008875:Middle Aged
D002096:C-Peptide; D004298:Dopamine