In vivo mutagenic effect of methyldopa. 1. Dominant lethal test in male mice

The dominant lethal test was used to evaluate the mutagenic potential of methyldopa, an antihypertensive drug, in male mice. In the series treated, animals were exposed to 480 or 960 mg/kg of the drug as a suspension in 1% gum acacia via the oral route. A separate group of males served as control. Following treatment each male of the control, as as well as the treated series, was mated to two untreated virgin females each week for a period of 6 consecutive weeks. All mated females were sacrificed on the 10th day of separation and their ovaries and uterine contents were examined. Corpora lutea, implantations and resorptions were recorded. The drug treatment did not impair the mating capacity and fertility. Pre- and post-implantation losses were assessed. Higher incidences of post-implantation losses and abortion, and lower incidences of total implantations particularly at higher dose levels clearly reveal a dominant lethal effect of the drug.