Influence of reserpine on iron absorption in rats.

The aim of our investigations was to define the influence of reserpine on iron absorption in rats. Iron absorption was determined in vivo at the 24th hour and in situ in a tied-off intestinal segment. Five-days treatment with reserpine (1 mg/kg b.wt) led to suppressed bone marrow erythropoiesis, manifested a considerable decrease in reticulocyte count and in a percentage of 59Fe-incorporation into newly formed erythrocytes. Increased plasma iron and decreased plasma ferritin levels were found. Iron absorption was found to be significantly increased, in spite of the suppressed erythropoiesis. The major conclusions of the experiments are, that reserpine interferes with the regulation of iron metabolism and erythropoiesis.

Influence of aluminium on erythropoiesis, iron metabolism and some functional characteristics of erythrocytes in rats.

The increased aluminium (Al) levels in serum of patients with chronic renal failure on hemodialysis are associated with impaired erythropoiesis and iron metabolism. The long term Al loading of rats (20 to 90 days) has similar effect. Data are still lacking about the effects after short-term aluminium treatment. The 7 day's treatment with Al2(SO4)3 in a dose 67.5 mg/kg b. w., i. m. m. significantly decreased hemoglobin, hematocrit, incorporation of 59Fe in newly formed erythrocytes and increased reticulocytes in absolute and relative counts. We observed a mild degree hypochromic, ferropenic, microcytic anemia and polychromazia in the available macrocytes. The immature erythroblasts were predominant forms in the erythroblastogram while the number of mature erythroblasts was decreased. Index of maturation of erythroblasts was lower, indicating inhibited erythroblast maturation. Plasma iron, TIBC, transferrin saturation and 59Fe absorption in the experimental group were significantly decreased. Spontaneous and mechanical hemolysis of erythrocytes were lower while erythrocyte deformability was increased. Obviously, Al treatment inhibits erythropoiesis and iron metabolism, probably hinders hemoglobin synthesis and erythroid cell maturation but does not affect the studied functional characteristics of mature erythrocytes negatively.

Effects of piracetam on erythropoiesis and leukopoiesis in rats.

Erythro- and leukopoiesis in rats after 10-day treatment with piracetam (2 x 200 mg/kg b.w.) were studied. Increase of reticulocytes and of 59-iron incorporation in newly formed erythrocytes accompanied by an increase of the index of maturation of erythroblasts in bone marrow were found suggesting a piracetam-induced stimulation of erythropoiesis. Piracetam also increased the number of small lymphocytes and the maturation of granulocytes in bone marrow. It is supposed that piracetam exerting a positive effect on the metabolic processes of erythroid, myeloid and lymphoid precursors stimulates their proliferation and differentiation.

Adrenergic dependence of the platelet aggregation in rats.

The paper examines the effect of different adrenergic agents influencing both the neuronal unit of the adrenergic transmitter system and its alpha- and beta-receptor components on the ADP-induced platelet aggregation. A considerable inhibition of the platelet aggregation is found under conditions of post-reserpine adrenergic block (16.06%, p less than 0.001) and blocking of the beta 1-adrenergic receptors with practolol, applied independently (45.06%, p less than 0.001) and prior to the treatment of the rats with dobutamine--beta 1-adrenoreceptor agonist (52.20%, p less than 0.001). The stimulation of these receptors with dobutamine accelerates the platelet aggregation by 41.04% (p less than 0.001). No changes in the platelet aggregation are found after treatment with phenoxybenzamine (nonselective alpha adrenergic blocker) and salbutamol (beta 2-adrenergic agonist). It may be concluded that the ADP-induced platelet aggregation depends to a certain extent on the functional state of the neuronal and beta-adrenoreceptor unit of the adrenergic transmitter system and possibly also on the metabolic processes connected with them.

[Beta1- and beta2-adrenergic effects on thrombocytopoiesis in rats]. / Beta1- i beta2-adrenergicheskie vliianiia na trombotsitopoéz u krys.

The influence of beta 1- and beta 2-adrenergic agent injections to rats during 3 days, on the main parameters of thrombocytopoiesis: platelet number and per cent of build up 75seleno-methionine in newly-formed platelets of rats has been studied. It is established that beta 1-adreno-stimulation with dobutamine (DB) increases both the number of platelets and the per cent of build up isotope. Practolol (PC), a beta 1-adrenergic blocking agent, used separately, and combined application of PC + DB lowered significantly the parameters studied. Salbutamol stimulation of beta 2-adrenergic receptors induced an insignificant rise in the thrombocytopoiesis parameters. beta 1-adreno-stimulation with DB results in activation, while beta 1-adrenoblocking with PC--in suppression of thrombocytopoiesis. Pretreatment with PC prevents DB stimulating effect on thrombocytopoiesis, thus evidencing the beta 1-adrenoceptor dependence on the process.

[The effect of prostaglandin inhibition with indomethacin on thrombocytopoiesis in rats]. / Vliianie na protaglandinovata inkhibitsiia s indometatsin vurkhu trombotsitopoezata u plukhove.

The influence of prostaglandin deficit after treatment with indomethacin was studied on thrombocytopoiesis of rats. There was a considerable inhibition of megakariocytopoesis as well as reduction in peripheral thrombocytes, while plasmic thrombocytopoietic activity was increased. It is assumed that prostaglandin deficit affects megakaryocytopoiesis not for lack of thrombocytopoetin, but probably by inhibiting directly proliferation and differentiation of megakaryocytes and their precursors in the bone-marrow. Prostaglandins deficit does not hinder the increase of thrombocytopoetin, but when such conditions are present the retardation of megakaryocates and thrombocytes occur by the mechanism of feed back negative relationship.

Effect of the post-reserpine adrenergic block on thrombocytopoiesis and thrombocyte aggregation in rats.

The effect of the post-reserpine adrenergic block (2 mg/kg for 3 and 6 days) on thrombocytopoiesis, bone marrow megakaryocytes (MKC) and thrombocyte aggregation was studied. A slight decrease in thrombocytes and a significant inhibition of 75selenomethionine incorporation in the newly-formed thrombocyte, more pronounced after 6-day reserpine treatment, was observed. The megakaryocytogram of the rats treated with reserpine for 3 and for 6 days manifested a similar significant decrease in MKC--as a total number and their separate stages. Thrombocyte aggregation was significantly inhibited, especially after the 6-day treatment. The inhibition of the megakaryocytopoiesis is probably the result of reduced metabolic processes, while thrombocyte aggregation probably results also from the serotonin depletion in the thrombocytes and the increased adrenaline level in the blood--phenomena observed after treatment with reserpine. It is concluded that the normal functions of the neuronal unit of the adrenergic transmitter system are necessary for the formation of an adequate number of functionally valuable thrombocytes.

Effects of indomethacin on erythropoiesis and plasma iron in rats.

The effect of indomethacin on erythropoiesis and plasma iron in rats is investigated after 3-day treatment. A more considerable decrease of erythrocytes, haemoglobin and plasma iron is observed, as well as an increase in reticulocytes and 59Fe incorporated in the newly-formed erythrocytes. The plasma bilirubin and lactate levels are also higher. Obviously, this suggests a regeneratory anaemia. It is concluded that prostaglandins are necessary for the normal iron metabolism and for erythropoiesis, but their absence does not prevent entirely the process of erythroid regeneration.

[The effect of neonatal thymectomy on thrombocytopoesis in rats]. / Vliianie na neonatalnata timektomiia vurkhu trombotsitopoezata u plukhova]

The influence of neonatal thymectomy on the number of thrombocytes, bone-marrow megakaryocytes (MKC) and activity of plasa thrombocytopoietin(TP) was studied in male rats 60 days after the manipulation--under normal and extreme (acute thromobocytopenia) conditions. It was established that under normal conditions neonatal thymectomy (NT) diminished the number of thromobocytes, the percentage of incorporated 75 selenomethionine in newly formed thromobocytes, the total number of MKC and their single stages--I, II, III, IV. The activity of plasma TP was not changed in normally thymectomized rats under normal condition, while in comparison with sham thymectomized rats, while it was considerably higher in acute thrombocytopenia. It is concluded that NT in rats inhibits megakarytocytopoiesis and diminishes thromobocyteson on this basis. NT stimulates biogenesis of TP- a specific humoral regulator of thrombocytopoiesis under conditions of acute thrombocytopenia.

Influence of nonselective beta-adrenergic impacts on the effects of thrombocytopoietin in mice.

The effects of plasma thrombocytopoietin are investigated in test mice against the background of nonselective beta adrenergic impacts. The changes in the thrombocytopoiesis are accounted for by the thrombocytes count and by the percentage of 75selenomethionine incorporated in the newly-formed thrombocytes. Plasma thrombocytopoietin is found to stimulate markedly thrombocytopoiesis on the background of beta-adrenergic stimulation with isoprenaline. Pretreatment with propranolol totally prevents this stimulation. Independent treatment with propranolol as a background of thrombocytopoietin considerably inhibits thrombocytopoiesis. The effects of thrombocytopoietin are found to depend on the state of the beta-adrenoreceptors: their stimulation has a synergic effect on thrombocytopoietin, while their blocking impedes its realization. The data established are indirect proof about the existence of beta-adrenoreceptors in the megakaryocyte series and probably in its precursors as well.