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The effect of indralin on frequency of mutations induced by radiation in germ cells, reciprocal translocations, and testicle weight of male mice. The level of protective effect against genetic damage varied depending on the radiation dose and spermatogenesis stage. The values of the defense coefficient ranged from 0.16 to 0.35.

The content of six lactate dehydrogenase isoenzymes in testes of rats exposed to electromagnetic field of 3-cm wavelength range was studied. The changes in their percent contents were found to be inhomogeneous compared with control. It is assumed that electromagnetic radiation affects the organs of the human urinogenital system. The results can be used for estimating the safety of persons professionally exposed to electromagnetic radiation of the industrial frequency range and in the therapy of diseases of the urinogenital system.

The effect of SHF radiation on the content of A and E vitamins in tissues of rat brain, liver and testis was studied. Among the tissues examined, the brain was found to be most sensitive to weak SHF radiation. The radiation induced a change in the ratio of A and E vitamins in the brain, which, in turn, increased the probability of damage to cell membranes. In the liver, the tocopherol level after irradiation remained unchanged, and in the testis it increased insignificantly. This suggests a high resistance of the antioxidant systems of liver and testis tissues.

There was a 30% increase in spermatozoids with microheads and a 3-fold increase in "young" spermatozoids at later times after irradiation of BALB/c mice a dose of 1.0 Gy. With radiation doses of 0.1-1.0 Gy, BALB/c and CBA mice (which differ in viability of spermatogenous cells, the number of Sertoli cells and total embryonal death rate) exhibited a significant increase in the preimplantation death at the stage of spermatogonia and stem cells. The results obtained indicate reduction of the fertilizing capacity of sperm which is probably realized as dominant lethal mutations.

The effect of long-term (9 months) exposure to electric field (17 kHz, 100 kV/m) on mouse testis has been investigated. The increase in destructive processes was noted in both spermatogenous epithelium cells and in steroid-producing cells; the histohematic barrier status changed. The results obtained indicate premature reproductive ageing of animals under the effect of electric field.

The hypothalamo-hypophysis-gonad system was studied in male rats 1, 3 and 6 months after external irradiation with doses of 2 and 3 Gy. Irradiation with a dose of 3 Gy was shown to cause a decrease in the level of LH and testosterone in blood plasma, impairment of steroidogenesis in the testes and diminution of their mass. All this was most pronounced 6 months after X irradiation. The morphofunctional status of prostate, inhibited by X radiation, was restored by that time.

In experiments with rats it was shown that with equal absorbed doses after single injection of 137Cs and local X-irradiation of testes the mutation yield in gametes was different when tested by the frequency of dominant lethals and half-lethals, reciprocal translocations, univalents, and chromosome fragments. A higher efficiency of whole-body irradiation as compared to local exposure of testes, with respect to genetic damages induction, and the statistically significant increase in the number of the damages during a long period of time after cessation of the absorbed dose formation indicated that indirect effects of whole-body irradiation contributed to the injury to hereditary structures and permitted to estimate approximately their contribution (up to 50%).

Mice (CBAxC57BL) F of both sexes were exposed within the 10 km zone of Chernobyl nuclear power station. Genetic damage of phone chronic effect of increased radiation in exposed adult mice and in the course of embryogenesis was studied. The total absorbed radiation doses in testes varied from 1.85 to 0.42 Gy in embryos and from 3.4 to 2.7 Gy in adult males. Increase of dominant lethal mutations (DLM) and abnormal sperm heads (ASH) was only observed right after the end of exposure of adult males. The yield of reciprocal translocations (RT) in these males was relatively low. Among the males exposed at the stage of early embryogenesis, 4 heterozygotes for RT were revealed. In other males of this group the RT yield was low.

In experiments on CBA and BALB/c male mice (3 months of age) and F1(CBA X C57BL/6) hybrids (at the age of 3, 12, and 24 months) a difference was noted in the radiosensitivity of spermatogenic epithelium stem cells displayed by the changes in their colony-forming ability in testicular tubules 42 days following local 60Co-gamma-irradiation. The older the hybrid mice the smaller was the number of spermatogenic epithelium stem cells.

The paper submits the results of studies on the kinetics of spermatogenous epithelium cell number after exposure to fast neutrons (60-300 cGy) and gamma-radiation (200-600 cGy). It was shown that a relative decrease in the quantity of spermatocytes is determined by an exponential dose-response curve with D0 of 35 and 120 cGy for neutrons and gamma-radiation respectively. For spermatides and spermatozoa a single D0 value of 20 and 55 cGy was obtained for neutrons and gamma-radiation respectively. As the radiation dose increases the recovery process in the epithelium is substantially decelerated. The equation T1/2 = T1/2(0)e0.0009D well describes the dependence of the half-recovery period T1/2 upon the equivalent dose.

It was shown that low-level beta-radiation of tritium is much more effective than gamma-radiation of 137Cs with respect to reduction of the mouse testis weight. The RBE coefficient increases from 1.8 at a dose of 1 Gy to 2.2-2.3 at 0.1 Gy. On the basis of the data obtained by the authors and those reported in the literature a quality factor is proposed for tritium: QF = 2. Using THO and Na36Cl labels a mean water content of the testis cells, necessary for the estimation of a tritium-radiation dose absorbed, has been determined: gamma ct = 0.70 +/- 0.02 ml/g.

On the basis of the data reported in the literature a model is proposed describing the kinetics of the post-irradiation recovery of the main spermatogenous epithelium populations. In studying the spermatogenous epithelium structure of rodents and comparing the experimental and theoretical curves the parameters necessary for the kinetics estimations have been quantitated and their specific variations analysed. From these the parameters have been obtained and the kinetic curves shaped with a reference to human spermatogenous epithelium.

Frequency of dominant lethal mutation, occurrence of spermatozoa with abnormal heads, and changes in the testis mass were studied after the administration to mice of 238Pu in doses from 7 to 1850 Bq/g. The frequency of genetic lesions in the testis was not a function of alpha-radiation dose. The rate of the testis mass decrease was a linear function of the dose absorbed. RBE of 238Pu-alpha-radiation, as determined by the incidence of abnormal spermatozoa heads and by the changes in the testis mass, was from 14 to 35 with regard to the chronic effect of gamma-radiation.

In experiments on BALB male mice a study was made of the dynamics of changes in the level of gonadotropic hormones and testosterone during 1-32 days in conditions of gamma-irradiation with the dose of 0.155 C/kg and dose rate of 0.512 mA/kg. A correlation was found between the number of germ cells and the level of sex hormones in blood plasma of irradiated animals.

In this paper, results of the morphological studies of mammalian testicular tissue after exposure of one of the testes to powerful laser radiation are reported. The results obtained are compared with those reported in the literature on the biological effect of penetrating radiation. No negative influence of powerful laser radiation is registered at the organism level. The criteria for estimation are the tissue response, morphological picture of spermatogenesis, and reproductive functions of exposed animals and of their progeny.

Comparative study of the genetic effect of some tritiated biogenic++ compounds and tritiated water was carried out. Reciprocal translocations induced in mice stem spermatogonia by 3H-glucose, 3H-glycine and 3H-lysine occur with similar frequency, whereas the difference in values of the absorbed doses of beta-irradiation in some cases was about two-fold. The highest genetic effect per unit of activity of 3H-nucleosides (3H-TdR and 3H-CdR) was revealed at lowest activities. The frequency of reciprocal translocations induced by 3H-TdR was twice as that induced by 3H-CdR.