What is the pathogenetic mechanism for the development of hypertension in DM

In Type 1 DM, as was already mentioned, hypertension is usually due to the development of nephropathy.

For Type 2 DM, things are not that simple. Both Type 2 DM and hypertension are frequent abnormalities in the general population and it could be considered that their coexistence is subject to chance. In certain cases, however, it appears that there is likely to be common cause for their development. Insulin resistance (see Chapter 3) has been incriminated as the common pathogenetic factor for the development of both Type 2 DM and hypertension. This is due to the fact that certain insulin actions are intensified in situations of insulin resistance, when it appears that there is in reality increased insulin sensitivity for certain actions of insulin. Thus, the hyperinsulinaemia that insulin resistance causes (as regards its action in the entry of glucose into the cells), results as a consequence in an intensification of other insulin actions, for which its sensitivity is preserved. Such actions include increased sodium and water retention from the distal convoluted tubules of the kidney (which leads to an increase in the total sodium load and total blood volume of the body) and the increased activity of Na-K-ATPase activity in the vascular smooth muscle fibres, resulting in increased intracellular concentration of sodium and subsequently of calcium, leading to vasoconstriction and increase of peripheral vascular resistances. In addition, insulin, through actions in the central nervous system, increases the excitation of the sympathetic nervous system, which can contribute to an increase of BP. Also, abnormal activity of insulin on the vascular endothelium in situations of insulin resistance, resulting in decreased production of nitrogen monoxide (NO), has been incriminated in increased vasoconstriction and final development of hypertension. Finally, as is the case in Type 1 DM, in Type 2 the development of nephropathy can also lead to the development and deterioration of hypertension.

It should not be overlooked, however, that certain medicines used in the treatment of idiopathic hypertension (especifically the thiazide diuretics and beta-blockers) most likely have a diabetogenic action, especially when given at high doses, which sometimes complicates the relationship between hypertension and DM. But, on the other hand, certain secondary forms of DM - especially due to endocrine disorders (such as pheochromocytoma, acromegaly, Cushing syndrome, etc.) or due to administration of medicines (such as glucocorticoids, oral contraceptive pills, etc.) - may be associated with development of both DM and hypertension.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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