| IDENTIFICATION AND USE: Methylamine is colorless gas. A liquid below 21 degrees F. Shipped as a liquefied compressed gas. it is used as an intermediate for accelerators, dyes, pharmaceuticals, insecticides, fungicides, surface active agents, tanning, dyeing of acetate textiles, fuel additive, polymerization inhibitor, component of paint removers, solvent, photographic developer, rocket propellant. HUMAN STUDIES: Olfactory fatigue occurs readily. Brief exposures to 20 to 100 ppm produce transient eye, nose, and throat irritation. No symptoms of irritation are produced from longer exposures at less than 10 ppm. Allergic or chemical bronchitis was reported in a worker exposed to methylamine at concentrations ranging from 2 to 60 ppm, and some irritation was noted at about 25 ppm. Stimulation of DNA synthesis in human fibroblast cultures by epidermal growth factor, insulin, and serum is inhibited by methylamine. ANIMAL STUDIES: Application of 0.1 mL of a 40% aqueous solution of methylamine to the skin of a guinea pig caused necrosis. Liquified methylamine caused change in guinea pig skin color with swelling and purple hue within a few minutes, gray and necrotic in 48 hr. At 12 days fresh granulation tissue had appeared covered by flat epidermis with no hair follicles. A drop of 5% solution in water applied to animal eyes caused hemorrhages in the conjunctiva, superficial corneal opacities, and edema. Methylamine caused interstitial pneumonitis progressing to fibrosis in rats. Methylamine was positive when tested for genotoxicity in a mouse lymphoma cell assay. Methylamine was negative when tested for genotoxicity in Salmonella typhimurium strains (TA1535, TA1537, TA97, TA98, and TA100) in the presence and absence of metabolic activation. Methylamine occurs endogenously from amine catabolism and its tissue levels increase in some pathological conditions, including diabetes. Methylamine is an endogenous aliphatic amine exhibiting anorexigenic properties in mice. The effects of methylamine on feeding depend on the hypothalamic release of nitric oxide and dopamine. ECOTOXICITY: Isolated individual fertilized eggs from zebrafish (Brachydanio rerio) developed in vitro can be used to elucidate possible actions of hazardous agents on embryogenesis. Methylamine at concentration 0.1 - 5 mg/mL incubation media caused mortality of most of eggs by cytotoxic effects essentially at stage 24. Malformations were not observed. |