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Male Sprague-Oawley rats were separated into nine groups and injected with cadmium (Cd) intraperitoneally every three days for 29 days for a total of nine injections. Injection doses ranged from 0 to 2.5 mg Cd/kg-1 of body weight. Twenty-four hours following Cd injections, rats received an acute whole body 60Co gamma radiation dose of 0, 3.62, or 5.43 Gray (Gy) at a dose rate of 3.04 Gy/min. Rats were sacrificed on day January 1994 7, or 21 post-irradiation. Co-insult groups which had been irradiated following Cd injections showed lower Cd concentrations in heart tissue than those groups which had been injected with Cd and sham-irradiated. Our data indicate that radiation contributed to clearance of Cd from the heart. The present study points to a need for researchers to continue to study links between the environment and disease.

Pigtailed macaque monkeys (Macaca nemestrina) were injected with 6.4 or 4.8 mg methylmercuric chloride/kg body weight in acute or fractionated dose schedules. Aphagia and adipsia occurring for several days after injection were followed by a period of apparent normality. The high-acute dose led to grossly observable sensorimotor symptoms that appeared 26 days following treatment and that were followed by death a week later. A three-stage response to mercury poisoning was proposed.

Two hundred and sixteen young adult male Sprague-Dawley rats, 80+5 days old, and each weighing approximately 220-250 gm, were injected IP every 3 days for 29 days for a total of 9 injections with 0, 1.0, or 2.5 mg CdCl2/kg body weight. Total cumulative doses were 0, 9.0 or 22.5 mg CdCl2/kg body weight. Twenty-four hours after the last cadmium injection (day 30), each rat was irradiated with a total-body exposure of 0, 3.62, or 5.43 Gray of gamma (60CO) radiation at a dose rate of 3.04 Gray/min. Eight rats from each of the 9 groups were sacrificed on day 1, 7, or 21. Highest levels of the creatine kinase enzyme were seen in radiation groups at day 1, indicating an immediate radiotoxic response. Enzyme levels decreased through day 21 indicating clearance of the enzyme from the plasma. Although statistically significant differences between the groups, cadmium, radiation, or days were not seen, cadmium did protect against radiation. This protective function is not explainable; however, we speculate that different conformations of metal-induced metallothioneln clusters exist to accommodate various metal ions. Further, that each kind of metal ion may have different and unique distribution patterns between the cluster centers which account for different functions.

Two hundred and sixteen male Sprague-Dawley (S-D) rats, 80 ± 5 days old and weighing 220-250 g each, were assigned at random to nine groups of 24 rats each. Rats were injected with cadmium (Cd) intraperitoneally every 3 days for 29 days for a total of nine injections. Injections doses were 0, 1.0, or 2.5 mg Cd kg-1 body weight. Twenty-four hours after the last Cd injection (day 30), each rat received an acute whole-body 60Co gamma radiation dose of 0, 3.62, or 5.43 Gray (Gy) at a dose rate of 3.304 Gy min-1. Eight rats from each of 9 groups were sacrificed on day 1, 7, or 21. High dose radiation administered 24 hours following the last dosage of Cd caused significantly elevated serum alkaline phosphatase levels, whereas high dose cadmium caused the enzyme to be significantly depressed. When Cd and radiation were used as the co-insult, the combination of high Cd-high radiation was more effective than either cadmium or radiation alone, suggesting a previously reported cadmium metal protection against the radiation. Although the precise mechanism is unknown, we speculate that the protection afforded by cadmium against radiation might be attributed to different conformations of metal-induced metallothionein cysteine clusters. Further, these clusters are likely dependent upon conversion between conformational forms requiring specific levels of metal ion site occupancy.

A total of 72 male Sprague-Dawley rats were assigned to three groups using a 3 X 3 factorial design. Animals were injected IP every three days for 29 days with 0, 1.0 or 2.5 mg CdCl2/kg of body weight. Total cumulative CdCl2 doses were 0. 9.0 or 22.5 mg/kg of body weight. Animals were sacrificed on day 1, 7 or 21 following injections. Liver and kidney tissues were collected and analyzed for Cd concentrations.The Cd-treated groups exhibited significant increases in Cd concentrations in both tissues. An average of 0.85, 19.86 and 48.44 μg/g of wet liver tissue and a mean of 0.78, 11.53 and 31.14 μg/g of wet kidney tissue for the 0, 1.0 and 2.5 mg CdCl2/kg of body weight groups, respectively, were observed.The amount of Cd in these tissues remained significantly high over the 21-day observation period.

A total of 216 young adult male Sprague-Dawley rats were used. Animals were injected intraperitoneally (IP) every 3 days for 29 days for a total of 9 injections with 0, 1.0, or 2.5 mg Cd/kg body wt. Twenty-four hrs after the last Cd injection (day 30), each animal was subjected to an acute sublethal total-body exposure of 0, 3.62 or 5.43 gray of gamma (60 Co) radiation at a dose rate of 3.04 gray/min. Eight rats from each of the 9 groups were sacrificed by cardiac exsanguination on post-irradiation day 1, 7, or 21. A significant high-dose cadmium-induced increase in AST enzyme was observed at days 1 and 7; however, by day 21 levels had returned to normal. The results suggest that high-dose cadmium increases were dose and time-dependent. No significant differences in AST values were observed between radiation only groups, days, or doses. However, significant dose-related differences were observed between high-dose cadmium and means, as well as between high and low-dose cadmium doses at days 1, 7, and 21. When the co-insult was used, significant differences were seen between the high cadmium-high radiation group and the mean at day one.

A total of 216 male Sprague-Dawley rats were used. Animals were injected IP every 3 days for 29 days for a total of 9 injections with 0, 1.0 or 2.5 mg Cd/kg body wt. Total cumulative doses were 0, 9.0 or 22.5 mg Cd/kg body wt. Twenty-four hrs after the last Cd injection (day 30), each animal was subjected to an acute sublethal total-body exposure of 0, 362 or 543 rads of gamma (60Co) irradiation at a dose rate of 304 rads/min. Eight rats from each of the 9 groups were sacrificed by cardiac exsanguination on post-irradiation day 1, 7 or 21.Radiation alone produced significant elevations of LDH. However, Cd alone or as the co-insult did not produce significant changes in enzymes levels. The molecular basis for the mechanism is not known.

Female Spanish goats were penned with males for up to 3 years and exposed continuously to 60Co gamma-radiation at average doses of 0, 2, 7 or 30 R/20-hour day. The median death time for the females receiving 30 and 7 R/day was 86 and 348 days, respectively. The ability to survive in the radiation environment was the only limiting factor affecting reproductive performance of the goats.

Fifteen 10-month-old crossbred boars were assigned to three groups of five each as follows: control, exposure to 200 r, and exposure to 400 r (air dose) acute gamma irradiation from Co60. Semen was collected weekly for 26 weeks after irradiation, then daily for 14 consecutive days. Numbers of sperm per ejaculate in treated boars were reduced at 7 weeks, reached a low point at 9 weeks, and returned to within the control range by 14 weeks after irradiation. One boar in the 400 r group failed to show any recovery in sperm production by 7 months but was producing about 50% as many sperm as the others by 14 months after irradiation. With the exception of this boar, semen characteristics of the three groups did not differ during the 14-day daily collection period. Oxygen utilization was depressed the 5th through 12th weeks after irradiation; motility was depressed the 7th through 11th weeks and percent abnormal sperm increased the 6th through 9th weeks. White blood cell concentration was depressed immediately after radiation, reached a low point at 4 days, then began a slow recovery, but had not returned to normal by 200 days; platelets dropped immediately after irradiation, reached a low level at 14 days, then returned to normal by 42 days after irradiation.

Data were obtained on the postnatal growth and sexual development of 57 control and 76 calves exposed to gamma radiation (400 r air dose, Co60) during the last half of prenatal life. Fetal irradiation caused a small decrease in growth rate. Ninety percent of the prenatally irradiated heifers were fertile when bred to normal bulls. Testis weights of the prenatally irradiated bulls were approximately 50% less than those of the control bulls when castrated at 187 days of age. In addition, bulls prenatally irradiated in the 5th or 8 month of fetal life produced 42% and 52% as many sperm as control bulls. Metabolic activity of the sperm from irradiated bulls was not different from that of the control bulls. Six percent of the dams died from acute irradiation sickness (average 23 days post-irradiation).

Semen was collected from 16 Hereford bulls, 2.5 to 6.5 years old, by the finger electrode method of electroejaculation. Intensities of collection were: depletion at 7-, 3-, or 2-day intervals, collection of three ejaculates three times per week, four ejaculates twice a week, two ejaculates twice a week, and two ejaculates once a week.Weekly depletion required an average of 20 ejaculates which contained an average of 20 × 109sperm in 260 ml. of semen. The first two, first four, and first ten ejaculates contained about 55%, 70% and 90%, respectively, of the total sperm. Depletions at 2- or 3-day intervals and collections of three ejaculates three times each week or four ejaculates twice each week produced about 15% more sperm then weekly depletion; two ejaculates twice a week and two consecutive ejaculates once a week produced 39% and 30%, respectively, of that obtained at weekly depletion. The individual bull variability in sperm output was much less for weekly depletion or collection of eight or nine ejaculates per week than the more frequent depletions or collection of four or two ejaculates per week. The mean sperm production per gm. of testis was 37 × 106sperm per week and ranged from 27 × 106to 47 × 106. Sperm output at depletion was highly correlated with testis weight, while sperm output at two ejaculates twice a week or two ejactulates per week was not significantly correlated with testis weight.

Three levels of testosterone propionate in oil (7.5, 37.5 and 187.5 µg. per pound of body weight per day) were administered in sequence to six boars and later to the same animals as castrates. Two additional castrates received three levels of testosterone beginning 2 months after castration.Each increase in testosterone level increased the seminal fructose concentration in boars. However, pretreatment fructose levels differed widely between boars; fructose response to added testosterone was not uniform and was dependent upon pretreatment level. All animals served the artificial vagina 2 days after castration, but ceased to serve by 19 days after castration. Testosterone injections, beginning 8 to 22 days after castration, restored the castrates to service; however, the fructose level of each animal was usually restored to approximately the pretreatment level of the animal as a boar and was not increased by higher levels of testosterone. More testosterone was required to restore castrates to service when 2 months intervened between castration and initiation of therapy and an increase in dose above the level which restored the castrates to service resulted in increased seminal fructose.

Groups of male and female Spanish goats approximately 15 months old were assigned to radiation areas receiving 60Co gamma radiation at average daily exposure of 0, 2·6, 7·2, 15, 30 and 40 R/20-hour day. The median lethal exposure at 7·2, 15, 30 and 40 R/day was 2650, 2415, 2450 and 2000 R, respectively, in females and 8330, 3600, 2770 and 2290 R, respectively, in males. Only 25 per cent of the animals exposed to 2·6 R/day died from radiation effects during the 48½-month period. The acute median lethal dose (80 R/hour) was 550 R. Survivors of the acute lethality studies were exposed to continuous irradiation at an exposure rate of 40 R/day beginning 86 days after the acute exposure. Median survival times did not differ significantly from controls not previously irradiated.