Adrenal enzymes of catecholamine biosynthesis and metabolism in spontaneously hypertensive rats

Zusammenfassung Es wird gezeigt, dass Dopa-Decarboxylase und Phenylethanolamin-N-methyl-transferase bei spontan hypertonischen Ratten im Vergleich zu normotonen Kontrollen leicht erhöht sind; hingegen wurde keine Veränderung der Catecholamin-abbauenden Enzyme festgestellt.     

Polyphosphoinositide metabolism in erythrocytes from spontaneously hypertensive rats

Summary Incorporation of³²P into di- and triphosphoinositides of erythrocytes from 1-month-old spontaneously hypertensive rats was lower, and diphosphoinositide content higher, than in controls. During development of hypertension these initial differences decreased and were even reversed.     

Polyphosphoinositide metabolism in erythrocytes from spontaneously hypertensive rats

Incorporation of 32P into di- and triphosphoinositides of erythrocytes from 1-month-old spontaneously hypertensive rats was lower, and diphosphoinositide content higher, than in controls. During development of hypertension these initial differences decreased and were even reversed.     

In vitro metabolism of progesterone by the adrenals of spontaneously hypertensive rats

Zusammenfassung Der Einbau des¹⁴C-Progesterons in Corticosteroide bei Nebennierensegmenten von Wistar-Ratten mit spontaner Hypertonie unterscheidet sich in nichts vom Einbau bei Nebennieren der Kontrollratten, was im Gegensatz zu Befunden mit regenerierten Nebennieren steht. Eine kausale Beziehung zwischen Nebennierenrindenfunktion und spontanem Hochdruck scheint ausgeschlossen zu sein.

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Dr. M. K.Birmingham is a Medical Research Associate of the Medical Research Council of Canada. This work was supported by grants from the Medical Research Council of Canada and the 33rd Degree Scottish Rite Committee for Research in Dementia Praecox. The authors thank Dr. R. A.Cleghorn for his interest in this project.     

Dopamine-beta-hydroxylase activity in stroke-prone spontaneously hypertensive rats

Dopamine-beta-hydroxylase (DBH) activity was higher in the serum, the mesenteric artery and the cerebral cortex of 4-week-old stroke-prone spontaneously hypertensive rats (SHRSP), and lower in the nucleus tractus solitarii than it was in spontaneously hypertensive rats (SHR).     

Serum dopamine-β-hydroxylase in spontaneously hypertensive rats

Zusammenfassung Es wird gezeigt, dass die Dopamin--Hydroxylase-Aktivität im Serum bei spontan hypertonischen Ratten im Vergleich zu normotonen Kontrollen nicht verändert ist.     

Monoamine oxidase activity in tissues of spontaneously hypertensive rats

Summary Monoamine oxidase (MAO) activity was assayed both in central and peripheral blood vessels of spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar Kyoto rats (WKR). The activity of MAO in the brain and peripheral vasculature was essentially the same in both SHR and WKR. It can therefore be concluded that central and peripheral vascular MAO activity is not altered in the genetically hypertensive animals.     

Hypothalamus-adenohypophysis-thyroid axis in spontaneously hypertensive rats (SHR)

Summary Increased basal TSH levels and an enhanced response to cold-exposure were apparent in the SHR accustomed to +30°C, whereas goitres and an increased amount of the anterior pituitary TSH were measured in SHR kept at +20°C.These studies were supported by grants from the Academy of Finland and Orion Pharmaceuticals Company, Helsinki. The technical help of Mrs Anneli v. Behr is greatly acknowleged.     

Tissue catecholamines following renal denervation in spontaneously hypertensive rats

Summary The delay in blood pressure increase observed in spontaneously hypertensive rats following bilateral renal denervation appeared to be due to a temporary reduction of the renal catecholamines content.This work was supported by grants from the Institut National de la Santé et de la Recherche Médicale (ATP 32-76-64, and AU 79-35) and from the Fonds National Suisse de la Recherche Scientifique (3.033.76)     

Blood pressure and impairment of endothelium-dependent relaxation in spontaneously hypertensive rats

Summary Correlation between hypertension and impairment of endothelium-dependent relaxation was demonstrated using aortae from certain strains of rats with various levels of spontaneous hypertension. It was also observed that the impairment of endothelium-dependent relaxation is the secondary change due to hypertension, and the level and duration of hypertension is the determinant factor of the impairment.     

Lower limit of cerebral autoregulation in normotensive and spontaneously hypertensive rats

Summary Cerebral autoregulation was examined in NTR and SHR. The lower blood pressure limit of autoregulation being 95 mm Hg in SHR was shifted upwards from 62 mm Hg in NTR.     

Blood pressure and impairment of endothelium-dependent relaxation in spontaneously hypertensive rats

Correlation between hypertension and impairment of endothelium-dependent relaxation was demonstrated using aortae from certain strains of rats with various levels of spontaneous hypertension. It was also observed that the impairment of endothelium-dependent relaxation is the secondary change due to hypertension, and the level and duration of hypertension is the determinant factor of the impairment.     

Isoprotenerol induction of pineal serotonin N-acetyltransferase in normotensive and spontaneously hypertensive rats

Zusammenfassung Verabreichung von Isoprotenerol, eines -adrenergen Agonisten, induziert einen signifikant höheren Anstieg der Aktivität der Serotonin-N-Acetyltransferase in der Epiphyse von spontan hypertensiven, im Vergleich mit normotensiven, Rattenmännchen. Derselbe Unterschied wurde auch bei Weibchen beobachtet, jedoch liegen die Aktivitätswerte bei spontan hypertensiven Männchen allgemein höher. Die durch Isoprotenerol erhöhte Induktion der Serotonin-N-Acetyltransferase erzeugt hinsichtlich der Catecholamine in den Pinealozyten von spontan hypertensiven Ratten eine veränderte Reaktivität der Achse -Rezeptor-Adenylzyklasesystem-Serotonin-N-Acetyl transferase.     

Acid excretion in young and adult Wistar Kyoto and spontaneously hypertensive rats

Summary Wistar Kyoto rats (WKy), the most widely accepted control for SH rats, show an inability to excrete acid appropriately when compared to another normotensive strain, SD. Coupled with the fact that KWy also develops sodium-sensitive hypertension, this makes them a more complex control than realized. At very young ages (<10-week-old), neither SH nor WKy show any deficiency in acid excretion.Acknowledgments. Supported by AHA grant 76 1019 and NIH grant AM 15458. The excellent secretarial help of Susan Dreux and Betty Mendelson is acknowledged.     

Enhanced reactivity towards flunarizine in cerebrovascular bed of spontaneously hypertensive rats

Cerebral blood flow (CBF) was measured and cerebrovascular resistance (CVR) was calculated in anesthetized spontaneously hypertensive rats (SHR) and normotensive rats (NR) following the administration of incremental dosages of i.v. flunarizine or papaverine. CBF and CVR changes following papaverine were the same in both groups of rats irrespective of the dose of the drug. The effect of flunarizine was much more pronounced in SHR than in NR. The results point out the greater dependency of basal cerebrovascular tone in SHR upon Ca2+ influx into vascular smooth muscle cells.