Peripheral dopamine synthesis and metabolism in spontaneously hypertensive rats

We have studied several parameters of peripheral dopamine synthesis and metabolism in spontaneously hypertensive rats during the development of hypertension. Compared to Wistar-Kyoto rats, there was an increased dopamine content in 8-week-old spontaneously hypertensive rats in the adrenals (1.6 +/- 0.1 vs. 1.2 +/- 0.1 nmol/pair in Wistar-Kyoto rats) and kidneys (97 +/- 12 vs. 63 +/- 7 pmol/g tissue in Wistar-Kyoto rats), but the dopamine content in peripheral organs from normotensive 4-week-old spontaneously hypertensive rats did not differ from Wistar-Kyoto rats. In the heart, the dopamine increase was observed in 14-week-old spontaneously hypertensive rats (systolic blood pressure: spontaneously hypertensive rats, 189 +/- 9; Wistar-Kyoto rats, 106 +/- 2 mm Hg;) in both atrium (spontaneously hypertensive rats, 133 +/- 14; Wistar-Kyoto rats, 86 +/- 20 pmol/g tissue) and ventricle (spontaneously hypertensive rats, 41 +/- 6; Wistar-Kyoto rats, 23 +/- 5 pmol/g tissue). Urinary free dopamine and dihydroxyphenylacetic acid, but not norepinephrine or normetanephrine, in spontaneously hypertensive rats significantly increased between the ages of 7 and 11 weeks, reflecting the dopamine changes in tissue and suggesting a selective increase of the rate of dopamine synthesis and release.(ABSTRACT TRUNCATED AT 250 WORDS)