methylthiouracil and Hypertension

Following oral administration of methionine in high doses to normotensive (NR) and spontaneously hypertensive (SHR) rats, its degradation product, homocysteine (HC), which is markedly elevated in serum, exerts an angiotoxic action directed to the aorta. This is accompanied by considerable loss of endothelium and degeneration, partly with dissolution of the media cells with formation of characteristic processes of the degenerating mitochondria, and by elevated HC and cystathion (CT) values in the aortic wall. At the arterial vessels of other organs similar alterations did not occur. There are quantitative differences between NR and SHR. In SHR, serum shows higher HC and CT concentrations than in NR, and the methionine-related aortic alterations are considerably more pronounced and develop earlier, with the additional formation of connective tissue. Here, a certain dependence on the methionine dose is noted, in contrast to NR, for which the magnitude of the reaction appears to be more related to the length of time of methionine application. Additional administration of atherogenic substances (cholestane-3 beta, 5 alpha, 6 beta-triol, cholesterol, angiotensin II, cholic acid with methylthiouracil) in SHR causes an exacerbation of the methionine-related aortic alterations. Only cholestane-triol has the same effect on the aortic wall in NR and SHR, with more accentuation in SHR. Cholestane-triol has, in NR as well as in SHR, a high coincidence with methionine-induced morphological reactions including the formation of mitochondrial processes. Simultaneous application of these two substances did not cause a potentiation of the effect. High doses of cholesterol bring about aortic alterations in SHR but not in NR. Thus, in addition to the disorder of fat and carbohydrate metabolism, disturbed protein metabolism is of decisive importance as a risk factor for coronary and other vascular diseases.

Topics: Angiotensin II; Animals; Aorta; Arteriosclerosis; Cholestanols; Cholesterol; Cholic Acid; Cholic Acids; Endothelium, Vascular; Homocysteine; Hypertension; Hypolipidemic Agents; Male; Methionine; Methylthiouracil; Microscopy, Electron; Mitochondria; Rats; Rats, Inbred SHR; Rats, Wistar; Tunica Intima; Vasoconstrictor Agents

Stable endogenous hypercholesterolemia and a slight, but stable hypertension developed under conditions of unrestricted behaviour in rabbits subjected for 4 months to daily prolonged (2-hour) interrupted stimulation of negative emotional zones of the hypothalamus through the implanted electrodes. Changes in cholesterol content were more noticable in case the stimulation was continued against the background of daily feeding of these rabbits with small doses of methylthiouracil.

Topics: Animals; Electric Stimulation; Humans; Hypercholesterolemia; Hypertension; Hypothalamus; Male; Methylthiouracil; Rabbits; Stress, Psychological

Topics: Adult; Blood Coagulation; Female; Humans; Hypertension; Liver; Male; Methylthiouracil; Middle Aged; Vitamin B Complex

Topics: Acetylcholinesterase; Acid Phosphatase; Adrenalectomy; Adrenocorticotropic Hormone; Animals; Body Weight; Cortisone; Dihydrolipoamide Dehydrogenase; Histocytochemistry; Hypertension; Hypothalamus; Iodine Isotopes; Male; Methylthiouracil; Monoamine Oxidase; NAD; Organ Size; Rats; Thyroid Hormones; Thyroidectomy

Topics: Animals; Arteriosclerosis; Cardiovascular System; Cholesterol; Dogs; Hypercholesterolemia; Hypertension; Methylthiouracil

Topics: Adrenal Gland Neoplasms; Adrenal Glands; Blood Pressure; Humans; Hypertension; Methylthiouracil; Neoplasms; Pheochromocytoma; Thiouracil