[Guanylate cyclase activity of the rabbit myocardium in normal conditions and in allergic states].

Activity of guanylate cyclase, regulation of the enzyme by means of hormones and other biologically active substances as well as level of cGMP were studied in rabbit myocardium of control animals and in animals with allergic impairment of the tissue. The enzyme was shown to exhibit no sensitivity to acetylcholine and histamine, which appears to occur as a result of the hormone-unspecific desensitization of the corresponding receptors in allergic impairment. Decreased basal activity of guanylate cyclase was accompanied by an increase in content of cGMP in myocardial tissue.

[Transport of calcium ions and content of cyclic nucleotides in fibroblast cultures from skin of patients with rheumatoid arthritis].

Content of cyclic nucleotides and the rate of Ca2+ transport into cells were studied in fibroblast cultures from skin of patients with rheumatoid arthritis within II-VI transfers during the stationary phase of growth. There were no differences as compared with controls. Effect of adrenaline on cAMP content was decreased as compared with the controls and the hormone influence on the rate of Ca2+ transport was dissimilar: in 5 patients out of the group of 13 persons--there was noted a stimulating effect (it was the case as in healthy persons), while in other patients the effect was either absent or adrenaline inhibited the Ca2+ transport.

[Adenylate cyclase system and calcium transport in the cardiac muscle of normal rabbits and rabbits with allergic heart damage].

A 2,3-fold increase of cAMP concentration in rabbit myocardium, increase in basal activity of adenylate cyclase and inhibition of phosphodiesterase were found in allergic impairment of heart muscle in response to repeated administration of normal horse blood serum. In presence of adrenaline and NaF the rate of adenylate cyclase activation was distinctly decreased, indicating the "desensitization" of the enzyme. At the same time, parameters of Ca2+ transport were altered; the alterations were expressed as intensification of 45Ca turnover in mitochondria and in the fraction of sarcoplasmic reticulum, as well as distinct increase in the initial rate of Ca2+ penetration into mitochondria and increase in content of calcium in the organelles.

[Calcium ion uptake by the skin fibroblast culture under normal conditions and in systemic diseases of the connective tissue].

Radioactive calcium (45Ca) uptake and the effect of adrenaline on this process was studied on the suspension of cells derived from the monolayer cultures of fibroblasts of the skin of healthy donors and of patients with systemic scleroderma and rheumatic fever. A significant increase of calcium uptake was shown in case of scleroderma in comparison with the normal and rheumatism cases. Adrenaline (2 X 10(-7)--2 X 10(-5) M) enhanced the rate of calcium uptake by fibroblasts in control and had the opposite effect in scleroderma.