Date of Award
Master of Science in Pharmacology
David R. DeFanti
The relationship between urinary dopamine levels and arterial blood pressure was studied in normal, unilaterally nephrectomized, and renal hypertensive male albino rats. Experimental hypertension was produced by a unilateral nephrectomy followed by compression of the contralateral renal artery. The two operations were spaced three weeks apart to allow for recovery. Nine weeks after-the-second operation; mean systolic blood pressure of the renal hypertensive control group increased to 170 mm Hg. Mean systolic blood pressure of the diethyldithiocarbamate (DDC)-treated renal hypertensive group decreased abruptly after two weeks of treatment and remained at 105 mm Hg throughout the nine week period. Mean systolic blood pressures of the normal and unilaterally nephrectomized group of animals remained between 100-12 5 mm Hg throughout the study. However, in comparisons with control groups, the systolic blood pressures of the DDC-treated unilaterally nephrectomized and normal groups of animals were significantly lower after four or seven weeks of treatment respectively. Urinary dopamine was extracted by adsorption onto alumina, converted to its trihydroxyindole fluorophore and measured spectrofluorimetrically. In comparisons with control groups, urinary dopamine levels (μ.g/24 hr, μg/kg/24 hr) did not differ significantly in either the normal or DDC-treated renal hypertensive group of animals. Mean dopamine levels remained relatively constant throughout the nine week period and varied from 15 to 27 μg/24 hr and 13 to 21 μg/24 hr in the normal and renal hypertensive group of animals respectively. Mean dopamine levels varied from 35 to 45 μg/kg/24 hr and 23 to 26 μg/kg/24 hr in the normal and renal hypertensive groups respectively. After seven weeks of treatment, the mean urinary dopamine levels (μg/24 hr) of the DDC-treated unilaterally nephrectomized group of animals were significantly higher than controls. Mean dopamine levels of the DDCtreated group increased from 11 μg/24 hr to 23 μg/24 hr after the seventh week of treatment. The control group remained relatively constant (15 μg/24 hr) within the same period. Mean body weights of the DDC-treated animals were significantly lower than controls after six, four, and two weeks of treatment in the normal, unilaterally nephrectomized, and renal hypertensive groups respectively. In all groups of drug-treated animals there was a correlation between decreased body weight, decreased amount of functional kidney tissue, and decreased arterial blood pressure. No correlation was found between arterial blood pressure and urinary dopamine levels.
Crossley, Harold Llewellyn, "Investigation of the Role of Dopamine in Maintenance of Arterial Hypertension" (1969). Open Access Master's Theses. Paper 189.