The antitumor drugs adriamycin and daunomycin were evaluated for effects on embryonal and fetal development in the rat and rabbit. Doses of adriamycin ranging from 1-2 mg/kg/day or daunomycin ranging from 1-4 mg/kg/day were administered ip to pregnant rats on days 6-15, 6-9, 9-12 or 12-15 of gestation. Both drugs were teratogenic in the rat, particularly when administered on days 6-15 or 6-9 of gestation. Relatively few anomalies resulted from treatment on days 9-12 or 12-15. On a mg/kg basis, adriamycin was the more potent teratogen, producing major anomalies at doses as low as 1.25 mg/kg. Similar anomalies, but at a lower incidence, were produced by daunomycin at dose levels of 4 mg/kg. Characteristic malformations included esophageal and intestinal atresia, tracheo-esophgeal fistula, hypoplasia of the urinary bladder and various cardiovascular anomalies. Neither drug was teratogenic when given iv to rabbits at doses up to and including 0.6 mg/kg/day on days 6-18 of gestation, but a high incidence of abortion occurred in rabbits treated with adriamycin.

A high incidence of sudden death due to ventricular fibrillation (VF) has been observed in dogs under chronic treatment with probucol, a new hypocholesterolemic agent. The present study describes the cardiac electrophysiologic properties of probucol-treated dogs and characterizes the electrophysiological response of these animals to manipulation of the autonomic nervous system. There was no significant difference in the spontaneous sinus cycle length, the QT interval, refractory period of the atrium, ventricle or A-V junction between normal and probucol-treated dogs. Epinephrine produced VF with few and sometimes no preceding premature ventricular extrasystoles. Electrical stimulation of the stellate ganglion induced VF in 16/19 dogs whereas stimulation of the right stellate ganglion induced VF in 1/19 dogs. Phenylephrine induced VF in 0/19 dogs, isoproterenol in 5/19 dogs, but phenylephrine + isoproterenol induced VF in 9/11 dogs in which isoproterenol did not produce VF. alpha (phentolamine) or beta (propranolol) blockade prevented initiation of VF by epinephrine, phenylephrine + is isoproterenol, and left stellate stimulation but alpha blockade did not prevent induction of VF by isoproterenol when isoproterenol alone produced VF. In this nonischemic model, we conclude that left stellate stimulation is a far more potent initiator of VF than right stellate stimulation and that induction of VF appears to require both alpha and beta adrenergic receptor stimulation.

Probucol was effective in lowering serum total cholesterol in mice at dietary livels as low as 0.0075%. It was also effective after a single 100 mg/kg I.V. dose in mice. The incorporation of acetate-(14)C into liver lipids of rats and mice was not significantly affected by probucol, although the results, especially in mice, make it impossible to rule out such an effect. Cholesterol absorption was estimated in rats using a dual isotope technique. The observed reductions were not statistically significant. Several liver enzyme activities were determined after probucol treatment in rats, and a significant elevation (32%) was observed in only one, glutamic dehydrogenase. Serum cholesterol was lowered markedly in cholesterol-fed cynomolgus monkeys by probucol. There was no effect on the excretion of neutral steroids and the observed increase in fecal bile acids after drug treatment could not be confirmed statistically.

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