An assessment of fertility in male workers exposed to molinate.

Molinate is a thiocarbamate herbicide used for weed control in rice fields. Since the late 1970s, findings from reproductive toxicology studies of rats have led to concern that molinate might affect human male fertility. Semen samples were collected from 272 formulation and production workers at three US plants.

The reproductive toxicity of molinate and metabolites to the male rat: effects on testosterone and sperm morphology.

Molinate causes an impairment in reproductive capability in the male rat. Administration of molinate to rats (40 mg/kg/day for 7 days) caused a distinctive sperm lesion. At higher doses of molinate (140 mg/kg for 7 days) this lesion was accompanied by morphological changes to the testis that were consistent with a delayed release of the late spermatids to the seminiferous tubular lumen, a process controlled by the release of testosterone.

Molinate: rodent reproductive toxicity and its relevance to humans--a review.

Molinate is a thiocarbamate herbicide used on rice. During the evaluation of the compound for regulatory compliance, an adverse effect on male reproduction in rats was observed. This led to extensive investigations in rats, mice, rabbits, dogs, monkeys, and humans, resulting in a description of the cause of the effect and establishing an empirical case for rodent specificity.

Assessment of the reproductive toxicology of bromochlorodifluoromethane (BCF, halon 1211) in the rat.

The effect of bromochlorodifluoromethane (BCF) on reproduction in the rat has been investigated in two studies. Pregnant female rats were exposed by inhalation to 1000, 10,000, or 50,000 ppm BCF for six hours a day on days six to 15 of gestation (day of mating = day 0). Exposure to 50,000 ppm BCF caused a reduction in maternal weight gain over the exposure period but there was no evidence of either teratogenicity or embryo/fetotoxicity at any concentration.

The post-natal fate of supernumerary ribs in rat teratogenicity studies.

A common occurrence in rat teratology studies, supernumerary ribs, have been considered to be indicative of teratogenicity by some authors but not to be so indicative by others. As a teratogenic event is, by definition a permanent change, a study to follow the fate of supernumerary ribs in the development of adulthood of the rat was undertaken. An established teratogen in the rat, aspirin, was used to increase the frequency of supernumerary ribs.