DNIC is a Structure Providing Specificity of Physiological Effects of NO.

Metabolism of nitric oxide (NO) donors: dinitrosyl iron complexes (DNIC), nitrosothiols (RSNO), and nitroprusside was studied on a chick embryo model. The obtained results give reason to assume that DNIC constituting the main pool of nitroso compounds in the vast majority of tissues are NO donors immediately interacting with the physiological target of NO, and other NO donors can perform this function after their transformation into DNIC. NO is released from DNIC not spontaneously, but under a joint influence of a factor destroying the complex and a target having chemical affinity for NO. A similar mechanism is apparently implicated in NO passage through the cell membrane.

Putative Role of Ligands of DNIC in the Physiological Action of the Complex.

In a relatively isolated system of avian embryo, the metabolism of NO, a component of the dinitrosyl iron complexes (DNIC), the main NO donor in most tissues, depends on the ligands that make up the complex. This fact corroborates the earlier hypothesis that these ligands perform a regulatory function in NO metabolism. It is also shown that nitrite injected into the embryo is not oxidized to nitrate like NO in DNIC, but is accumulated outside the amniotic sac. Normally, nitrite is present in an embryo in trace amounts. These facts suggest that NO in the embryo is transferred from the donor molecule to a target in the embryo tissues further transformed with minimum oxidation to nitrite.

Increased Stress Resistance of the Offspring Egg Cross Chickens when Using Biologically Active Substances before Hatching.

Application of biologically active compositions, containing colamine, succinic acid, serine, and pyridoxine hydrochloride before hatching decreased hatchery waste and increased hatching rates by 2.65% and egg hatchability by 1.85%. The chicks of the experimental group exhibited a decrease in the intensity of lipid peroxidation, which indicated a greater resistance to stress. This conclusion is additionally based on an increase in the Krebs index by a factor of 1.74 (p < 0.01) and leukocyte intoxication index by 5.53% and a decrease in the lymphocyte-granulocyte index by a factor of 1.75 (p < 0.05) and leukocyte index by 1.67% (p < 0.05). The body length of the offspring of the experimental group was by 2.12% less and safety for 60 days of cultivation was 3% higher compared to the control.

Synthesis and Metabolism of Nitric Oxide (NO) in Chicken Embryos and in the Blood of Adult Chicken.

In chicken embryos, nitric oxide (NO) is accumulated in the pool of NO donors: S-nitrosothiols, nitrosyl-iron complexes, high-molecular-weight nitro-compounds. Oxidation of NO to nitrate occurs with different intensity in the embryos of different chicken breeds. In some embryos, NO donors accumulate almost without oxidation. Stable concentration of NO donors and nitrate in the blood of adult chicken is a result of dynamic equilibrium between NO synthesis and elimination (oxidation, consumption by other tissues, and excretion). As NO oxidation occurs mainly not in the blood, but in other tissues, decomposition of NO donors and NO oxidation are determined the properties of these tissues, in particular, the presence of physiological targets of NO, rather than spontaneous processes. Hence, evaluation of the intensity of NO metabolism is important for prediction of the efficiency of preparations containing NO donors and stimulators of its synthesis.

Mechanisms of Specific Embryonic Effects of Nitrogen Oxide.

The study of NO metabolism in chicken embryos showed that the intensity of oxidation of both endogenous and exogenous for the embryo NO donors to nitrate is determined by the presence or state of NO targets, rather than donor concentration. The mechanism of this oxidation and its physiological role are discussed. It was also shown that oxidation product nitrate is actively eliminated from the amnionic sac.