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2760. Lead hampers reproduction in rats
The chemicalenvironment
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in bone ossification with all types of treatment. The observed embryotoxic effects and foetal toxicity appeared to be secondary to the maternal toxicity rather than a direct effect on the foetus. In contrast, direct injection of TLC into the amniotic fluid resulted in a doserelated foetal mortality, which reached 96~ at the highest dose level. The iv injection of TLC indicated that the placental transfer of TLC was greatly increased when the maternal blood concentration exceeded the threshold saturation capacity of the erythrocytes; below this level the rate of transfer was very limited. The second paper cited shows the important adverse effect of inorganic lead on reproductive function in the rat. Oral administration of lead acetate (PbAc) in doses of 5 or 100/tg/day for 30 days resulted in mean whole blood concentrations of 19 and 30/~g Pb/ 100 ml, respectively, in male rats. With the higher dose, the weight of the prostate increased as a result of hyperplasia, reaching up to twice the control weight, and impotence and reduced sperm motility were observed. Four rats (of 20) with an unusually high blood Pb concentration of 50 #g/100 ml also showed a marked reduction in testicular weight. Histological examination of the affected testes revealed lesions of the seminiferous tubules and arrest of spermatogenesis. In treated females, the whole blood concentrations of Pb were higher than in males, 30 and 53 #g/100 ml, respectively, compared with 19 and 30#g/ 100 ml. At the 5/~g dose level, oestrous cycles became irregular, while at the 100/tg level the animals had persistent vaginal oestrus after a period of normal oestrus. The latter group developed ovarian follicular cysts, with production of a reduced number of corpora lutea. Hepatic microsomal enzyme activity was significantly depressed in both sexes, indicating a suppression of the normal hepatic detoxication mechanisms. The third paper cited describes the appearance of cardiac abnormalities in chick embryos exposed at 48 hr to doses of 5-80 #g PbAc/egg, injected into the albumin. Aortic stenosis was seen in 19'~/,of the whole series of embryos treated in this way and examined when 8 days old, the incidence rising from 10 to 30170with increasing Pb dosage. Aorticvalve defects appeared in 16'~0and valve defects of the pulmonary artery in 5~o, the latter lesions being confined to embryos receiving more than 15 #g PbAc. Abnormalities of the atrioventricular valves occurred in 11'70 and an abnormally thin ventricular wall in 5~o. Many of the chick hearts showed several of these defects simultaneously. In 30 control eggs, injected with distilled water at the appropriate time, the only cardiac defects were a malformed pulmonary valve in one embryo and a defective atrioventricular valve in one other. It can be concluded therefore that under the conditions of this study inorganic Pb seriously interfered with cardiac morphogenesis in the chick. 2761. Aldehydes and the blood pressure Egle, J. L., Jr., Hudgins, Patricia M. & Lai, F. M. (1973). Cardiovascular effects of intravenous acetaldehyde and propionaldehyde in the anesthetized rat. Toxic. appl. Pharmac. 24, 636. Inhalation of about 3 ltg acetaldehyde/ml or slightly more propionaldehyde for 1 min caused an increase in blood pressure in the anesthetized rat, while in a concentration of 12-25/~g/ml these aldehydes accelerated the heart rate (Cited in F.C.T. 1973, 11,922). The study cited above demonstrated the biphasic nature of the effects of these aldehydes. A consistent dose-related rise in blood pressure, slightly reduced by adrenalectomy and more markedly diminished by pretreatment with reserpine or phentolamine, was recorded in anaesthetized rats given acetaldehyde or propionaldehyde in an iv dose of 5-10 mg/kg.
787
in bone ossification with all types of treatment. The observed embryotoxic effects and foetal toxicity appeared to be secondary to the maternal toxicity rather than a direct effect on the foetus. In contrast, direct injection of TLC into the amniotic fluid resulted in a doserelated foetal mortality, which reached 96~ at the highest dose level. The iv injection of TLC indicated that the placental transfer of TLC was greatly increased when the maternal blood concentration exceeded the threshold saturation capacity of the erythrocytes; below this level the rate of transfer was very limited. The second paper cited shows the important adverse effect of inorganic lead on reproductive function in the rat. Oral administration of lead acetate (PbAc) in doses of 5 or 100/tg/day for 30 days resulted in mean whole blood concentrations of 19 and 30/~g Pb/ 100 ml, respectively, in male rats. With the higher dose, the weight of the prostate increased as a result of hyperplasia, reaching up to twice the control weight, and impotence and reduced sperm motility were observed. Four rats (of 20) with an unusually high blood Pb concentration of 50 #g/100 ml also showed a marked reduction in testicular weight. Histological examination of the affected testes revealed lesions of the seminiferous tubules and arrest of spermatogenesis. In treated females, the whole blood concentrations of Pb were higher than in males, 30 and 53 #g/100 ml, respectively, compared with 19 and 30#g/ 100 ml. At the 5/~g dose level, oestrous cycles became irregular, while at the 100/tg level the animals had persistent vaginal oestrus after a period of normal oestrus. The latter group developed ovarian follicular cysts, with production of a reduced number of corpora lutea. Hepatic microsomal enzyme activity was significantly depressed in both sexes, indicating a suppression of the normal hepatic detoxication mechanisms. The third paper cited describes the appearance of cardiac abnormalities in chick embryos exposed at 48 hr to doses of 5-80 #g PbAc/egg, injected into the albumin. Aortic stenosis was seen in 19'~/,of the whole series of embryos treated in this way and examined when 8 days old, the incidence rising from 10 to 30170with increasing Pb dosage. Aorticvalve defects appeared in 16'~0and valve defects of the pulmonary artery in 5~o, the latter lesions being confined to embryos receiving more than 15 #g PbAc. Abnormalities of the atrioventricular valves occurred in 11'70 and an abnormally thin ventricular wall in 5~o. Many of the chick hearts showed several of these defects simultaneously. In 30 control eggs, injected with distilled water at the appropriate time, the only cardiac defects were a malformed pulmonary valve in one embryo and a defective atrioventricular valve in one other. It can be concluded therefore that under the conditions of this study inorganic Pb seriously interfered with cardiac morphogenesis in the chick. 2761. Aldehydes and the blood pressure Egle, J. L., Jr., Hudgins, Patricia M. & Lai, F. M. (1973). Cardiovascular effects of intravenous acetaldehyde and propionaldehyde in the anesthetized rat. Toxic. appl. Pharmac. 24, 636. Inhalation of about 3 ltg acetaldehyde/ml or slightly more propionaldehyde for 1 min caused an increase in blood pressure in the anesthetized rat, while in a concentration of 12-25/~g/ml these aldehydes accelerated the heart rate (Cited in F.C.T. 1973, 11,922). The study cited above demonstrated the biphasic nature of the effects of these aldehydes. A consistent dose-related rise in blood pressure, slightly reduced by adrenalectomy and more markedly diminished by pretreatment with reserpine or phentolamine, was recorded in anaesthetized rats given acetaldehyde or propionaldehyde in an iv dose of 5-10 mg/kg.