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Biomedical subjects

L Sirakov

Publications and source records attributed to L Sirakov.

At least 19 recordsLinked to original sources
PubMed1988

Insulin action in vivo on a growth-related protein kinase in lactating mouse mammary gland.

1. A cytosol serine-protein kinase was isolated and partially purified from lactating mouse mammary gland which is cAMP-independent, inhibited by the bioflavonoid quercetin and probably connected to the growth of mammary cells. 2. After supra-physiological doses of insulin (0.4 IU daily) given in vivo the activity of this kinase rises 2.4 times, but at 5 times higher doses of insulin the activity was completely inhibited. 3. The biphasic effect of insulin suggests that this protein kinase might be connected to the growth effect of the hormone.

Animals↗
PubMed1987

Discrepancy between aldosterone production and renin-angiotensin system activity in Brattleboro rats.

It was demonstrated before that in addition to their typical changes in water-sodium-potassium balance Brattleboro rats, homozygous for hypothalamic diabetes insipidus (DI), revealed a discrepancy between aldosterone level and plasma renin activity (PRA). In the present study PRA was significantly increased (79%), and concomitantly juxtaglomerular (JG) index was increased, reflecting an increased secretory activity of renin-producing JG cells. Plasma concentration of aldosterone was significantly lower (-36%) in DI rats than in their Long Evans (LE) controls. Adrenal blood flow rates were not significantly different in both groups of rats but aldosterone concentrations in the adrenal venous effluents were significantly lower (-66%) in DI rats than in LE rats, suggesting that in vivo production rate of aldosterone was reduced in DI rats. This assumption was confirmed by morphometric data of zona glomerulosa. Our results demonstrated a significant reduction (50%) of angiotensin II receptors in the adrenal glands of DI rats, referring to the number of binding sites and to Kd. This finding threw light on the dissociation between a decreased aldosterone production and stimulated renin-angiotensin system in DI rats.

Adrenal Glands↗
PubMed1979

[Effect of biological agents on glucose-14C utilization by erythrocytes varying in age].

The authors examined young, adult and old erythrocytes from rabbits, aged 15,35 days and 3--4 years. They measured the amount of glucose 14C transfere and metabolized by the erythrocytes during 2-hour incubation at 37 degrees C in a suitable medium. A series of erythrocytes from the three age groups were examined without treatment with chemical agents. Other series of erythrocytes were treated 1 degree minutes before incubation and during its performance with various biological active substances insulin, ACTH, adrenaline, STH, 3AMP, ClCl2. There were differences due to the age in the nontreated erythrocytes. Erythrocytes increased their permeability for grucose and thus its amount was raised in the cells after treatment with insulin. ACTH inhibited this process. Adrenaline, STH, 3AMP and CaCl increased the amount of glucose in the young erythrocytes, obtained from the young animals. The data showed differences in the transfer of glucose 14C and its metabolism in accordance with the chemical and biological properties of the biological agents as well as in accordance with the age of erythrocytes and the animals.

Adrenocorticotropic Hormone↗