Influence of parathyroidectomy on blood pressure and vascular reactivity in spontaneously hypertensive rats.
We investigated the influence of parathyroidectomy (PTX) on blood pressure (BP) and hindlimb vascular reactivity to noradrenaline (NA) and vasopressin (AVP) in male spontaneously hypertensive (SHR) and normotensive Wistar Kyoto rats (WKR). Three groups of SHR and WKR, respectively, were investigated: Sham-operated (SO) rats on a normal calcium intake (0.95%), SO rats on moderately elevated calcium intake (1.6% calcium diet) and PTX rats on the 1.6% calcium diet. At the end of the experiment (3 months), directly or indirectly measured BP was significantly lower in the PTX-SHR group on the 1.6% calcium diet than in SO-SHR on the same diet. In WKR groups, no changes of BP were recorded. Hindlimb perfusion with oxygenated Tyrode's solution for cumulative dose response curves with NA (0.1-1000 x 10(-6) M) and AVP (0.5-500 x 10(-9) M) showed no differences between PTX and SO groups. Maximal pressures and ED50 for agents used were significantly higher in SHR than WKR groups (p less than 0.05). The results support the hypothesis that the parathyroid glands contribute to high blood pressure in SHR. However, the antihypertensive action of PTX was not mediated by a change in hindlimb vascular reactivity.
Wiecek
A
A
Department of Internal Medicine, University of Heidelberg, FRG.
Kuczera
M
M
Ganten
U
U
Ritz
E
E
Mann
J F
JF
D000818:Animals; D001794:Blood Pressure; D001808:Blood Vessels / Q000502:physiology*; D002118:Calcium / Q000097:blood; D002136:Calcium, Dietary / Q000494:pharmacology; D006614:Hindlimb / Q000098:blood supply; D008297:Male; D009994:Osmolar Concentration; D010280:Parathyroid Glands / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR / Q000097:blood / Q000502:physiology*; D011919:Rats, Inbred Strains / Q000502:physiology*; D011921:Rats, Inbred WKY; D014664:Vasodilation
D002136:Calcium, Dietary; D002118:Calcium