[The vasopressin-, oxytocin- and corticoliberin-synthesizing structures of the hypothalamus in rats with diabetes mellitus under hypoxic exposures]. / Sostoianie vazopressin-, oksitotsin- i kortikoliberinsinteziruiushchikh struktur gipotalamusa u krys s sakharnym diabetom pri gipoksicheskikh vozdeistviiakh.

Hypothalamic mechanisms of neurohormone regulation of endocrine pancreas in diabetes mellitus, adaptation to hypoxia and their combination were studied on Wistar rats. To evaluate the condition of supraoptic nucleus (SON) secretory function, paraventricular subnuclei (PVH) of hypothalamus and endocrine pancreas, we used radioimmunoassay, immunocytochemical, morphometrical and histochemical methods. Hyperglycemia, hypoinsulinemia, glucagon and somatostatin synthesis and secretion intensification in diabetes mellitus is accompanied by marked reorganization of hypothalamic neurohormones (CRF, vasopressin, oxytocin) secretion with corresponding signs of activity increase of synthesizing their hypothalamus nuclei and subnuclei and also ACTH, corticosterone, cortisol rise in blood. Adaptation to hypoxia caused hypoglycemia, activated insulin biosynthesis, changed glucagon and somatostatin synthesis and secretion. CRF concentration, corticosterone and cortisol, ACTH in blood was not changed, vasopressin concentration lowered, oxytocin in median eminence of hypothalamus increased to a higher degree than in diabetes. Adaptation to hypoxia corrected impaired hormone balance and state of Langerhans islets (beta-cells destruction process inhibition, insulin biosynthesis stimulation, glucagon and somatostatin secretion decrease) in diabetes mellitus, hypothalamic neurohormones participating in this process.

[Status of vasopressin-, oxytocin- and corticoliberin-synthesizing structures of the hypothalamus in experimental diabetes mellitus in rats of different sexes]. / Sostoianie vazopressin-. oksitotsin- i kortikoliberinsinteziruiushchikh struktur gipotalamusa pri éksperimental''nom sakharnom diabete u krys razlichnogo pola.

The endocrine status of the pancreas and the hypothalamic neurosecretory nuclei were studied by radioimmunoassay, immunocytochemical, morphometric and histochemical methods in Wistar rats of both sexes with experimental diabetes mellitus. The development of diabetes mellitus was characterized by beta-cell destruction and insulin concentrations reduction in these cells and the blood, by increase of glucagon and somatostatin levels in the alpha- and delta-cells, respectively, as well as by the growth of these substances concentrations in the peripheral blood. These changes were parallelled by activation of the vasopressin-, oxytocin and corticoliberin-synthesizing neurones of the paraventricular and supraoptic nuclei of the hypothalamus, as evidenced by morphometric findings and by increase of the blood vasopressin and corticoliberin concentrations and oxytocin level in the hypothalamus. Experimental diabetes mellitus was found to be characterized by activation of the hypothalamo-hypophyseo-adrenal system. Functional differences in the contribution of vasopressin- and oxytocin-synthesizing neurones of the hypothalamic nuclei in the pathogenesis of the disease is shown, as are their sex-specific reactions.

[Reactions of the paraventricular hypothalamic nucleus and of the dorsal hippocampus in long-term adaptation to hypoxia]. / Reaktsii paraventrikuliarnogo iadra gipotalamusa i dorsal'nogo gippokampa pri dolgovremennoi adaptatsii k gipoksii.

In experiments on 17 Wistar rats the physiological activity was studied after stereotaxic electrode implantation according to the indices of the pulse rate and impedance, hypothalamic paraventricular nucleus and dorsal hippocamp under conditions of 30-day barochamber hypoxia (6 hours daily), at the imitated "height" of 6 km. The change recurrence was found, characterized by a prolonged period of the nucleus activation with parallel protective relieving inhibition of the dorsal hippocamp, followed by a fall in the nucleus activity and a marked hippocamp stimulation with hyporeactivity of the organism on hypoxia itself. The subsequent wave of the nucleus activation was transitory and was accompanied again by the hippocamp inhibition. The observed cyclic changes in physiological processes of the nucleus and hippocamp showed the mechanism of development of the organism adaptation to hypoxia.