[Mechanism of the central action of insulin on kidney function]

Injection of insulin to the CSF in the presence of spontaneous diuresis and hydration gives rise to the growth of reabsorption of osmotically free water accompanied by high tubular transport, as well as to the development of antinatriuresis and inhibition of diuresis. Experiments with a preliminary blockade of beta-adrenoreceptors with propranolol or administration of a beta-blocker following insulin injection demonstrated beta-adrenoreactive brain structures to be involved in the mechanism of action of insulin. Secondary activation of vasopressin secretion and release in the blood may be mediated via these structures, as a result of which reabsorption of osmotically free water in renal tubules gets increased. Thus, CSF insulin effects its influence on renal function via the central neurohumoral mechanisms which work due to beta-adrenergic brain receptors.