摘要:

The cell pathology of experimental hypertensioninduced by endocrine methods was traced by histochemical methods, autoradiography and electron microscopy. Arterial mucopolysaccharide synthesis is increased in rats made hypertensive with desoxycorticosterone and sodium chloride overload, and in rats with adrenal regeneration hypertension. Autoradiographs show a high uptake of radioactive sulphate in the mesenteric arteries but no increased venous uptake. New cell formation in the heart, arteries and kidney was traced with 3H-thymidine autoradiography in the same experimental models. The most marked increase in 3H-thymidine labelling occurs in arterial smooth-muscle at sites of plasmatic vasculosis which later evolve into hypertensive necrotising arteritis, and this may be reparative in nature. The more generalised but less marked labelling of smooth muscle is a compensatory response to the high blood pressure. Electron microscopy in adrenal regeneration hypertension indicates that fibrin and platelets leak into the arterial wall at focal segments of plasmatic vasculosis. The electron microscopy of renal biopsies from patients with hypertension due to Cushing’s syndrome reveals a form of vascular hyalinosis different from that described in benign essential hypertensio

ISSN:1663-2818    

DOI:10.1159/000178178

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

The effect of the thyroid hormones on the configurational state of mitochondrial malate-dehydrogenase has been investigated. A new, heavy form of malate-dehydrogenase (9 S) has been purified from pig-heart mitochondria. The physicochemical and chemical properties of this enzyme, compared with those of the well-known mitochondrial enzyme (5 S), show that 9S protein differs from the lighter form by: (a) content of sulfydryl groups, (b) the presence of tryptophan, (c) immunochemically. The configuration of this new form of malate-dehydrogenase appears to be that of a tetramer composed of two non-identical subunits. Low concentrations of thyroxine and iodine cyanide are able to dissociate the 9 S enzyme into smaller subunits whose sedimentation coefficients approximate 5 S. The disaggregation of the 9 S protein is coincident with an enhancement of the enzyme activity in the order of 50% over the initial value. The degree of activation is strongly influenced by the pH of incubation, the greatest effect being obtained at pH ranging between 7.0 and 7.4. One of the subunits, the ‘catalytic’, shows physico-chemical and immunochemical properties similar to those of the well-known mitochondrial enzyme (5 S). The other, ‘regulatory’ subunit, is devoided of enzyme activity and is immunochemically different from the ‘catalytic’ one. A scheme suggesting the allosteric effect of thyroxine in the regulation of malate-dehydrogenase activity i

ISSN:1663-2818    

DOI:10.1159/000178179

出版商:S. Karger AG    

年代:1970

数据来源: Karger

摘要:

Control by the central nervous system of neural and humoral thermoregulatory mechanisms was studied in conscious baboons. Local cooling and warming of the anterior hypothalamus respectively stimulated and inhibited the sympathico-adrenomedullary system and the adrenal cortex. These endocrine responses correlated with physical heat gain and heat loss and with thermoregulatory behavior. Evidence of and essential role of the sympathico-adrenomedullary system in thermogenesis was obtained when baboons were treated with a ganglionic blockingagent. Intrahypothalamic infusion of norepinephrine lowered internal temperature as did central warming, suggesting that this monoamine may be a central neurotransmitter triggering heat loss. Systemic and intrahypothalamic infusion of adrenergic blocking agents provided evidence for an adrenergic mechanism mediating reciprocal secretion of growth hormone and insulin.

ISSN:1663-2818    

DOI:10.1159/000178180

出版商:S. Karger AG    

年代:1970

数据来源: Karger