Humans and animals encounter various stress factors in the process of life.Numerous data demonstrate that stress may serve as the pathological basis of the development of various diseases -the number of which has been increasing continually [1, 3, 61. It is believed that the prolonged influence of hormones which participate in the formation of the stress reaction and which cause grave disturbances in the metabolism of lipids, carbohydrates, and electrolytes is the basis of the development of diseases in the presence of prolonged stress on the organism [3].There are data showing that mental trauma is the cause of approximately 80% of all cases of Basedow's disease [4].However, it is the function of the thyroid axis in particular under the influence of stress on the organism that is least studied [7]. The influence of stress factors on the process of secretion and metabolism of the thyroid hormones, as well as the changes induced by these factors in target organs, have been studied inadequately.In this context, the aim of the present study was the investigation of the influence of immobilization stress on the process of secretion of the thyroid hormones.
MATERIALS AND METHODSSixty male Wistar rats weighing 180-200 g were used in the experiments.The rats were kept in a vivarium under standard conditions on a normal diet. Immobilization was accomplished by fixing the rats on their back for 2 min, with subsequent repetition of the procedure every 2 min. This interval cho-Laboratory of the Biochemistry of Hormones, Institute of Biochemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent. sen in connection with indications [2] that this is the minimum time between exposures during which the bioelectrical and vegetative reactions have time to return to the initial level.Following immobilization the rats were anesthetized with a preparation of Calypsol (Calypsol, Budapest, Hungary), 25 mg/kg; they were fixed on their backs; the thyroid gland was exposed by an incision along the central line of the trachea; and the veins taking off from its lobes were dissected. The operative site was treated with a solution of heparin (0.025 AU/ml) in order to prevent thrombns-formation. The vessels leaving the cranial pole and the medial surface were calcined; the blood was collected from the caudal pole of both lobes by means of a micropump system. All the preparations under investigation were administered to the animals intraperitoneally.
Cardiac hypertrophy leads to a reduction in myocardial energy reserves, rendering it more susceptible t o ischaemic injury. The aim of this study was t o investigate the role of glycogen in energy provision and ischaemic protection in hypertrophy using 13C NMR and biochemical techniques.Myocardial hypertrophy (HT) was induced in rats b y intrarenal banding of the aorta. 9 weeks post surgery, isolated hearts were perfused at constant flow (14ml/min) with Krebs-Henseleit buffer containing 5mM l-13C glucose, 0.3mM palmitate and insulin (from 0.1 t o 5mU/ml) for 45 min. Flow rates were reduced t o Iml/min for low flow ischaemia (LFI).
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