Interspecies differences

Metabolic differences betw een humans and other animals may account for some of the interspecies differences in specific organ toxicity of trichloroethylene (see below). Among humans, sexual differences due mainly to the effects of body fat content on trichloroethylene absorption are expected based on PBPK modeling (see Section 2.3.5). 

The liver is an organ that shows variable effects from trichloroethylene among species, and this can probably be attributed to interspecies differences in metabolism (see Section 2.4.2.1). Specifically, the apparent difference in susceptibility to trichloroethylene-induced hepatocellular carcinoma between humans and rodents may be due to metabolic differences (see Section 2.4.2.3). Kidney effects are also variable among species. Humans and mice are less sensitive than rats. In rats exposed chronically to trichloroethylene, toxic nephrosis characterized as cytomegaly has been reported (NTP 1988). The kidney effects in rats do not seem to be related to an increase in alpha-2 -globulin (Goldsworthy et al. 1988). Effects on the nervous system appear to be widespread among species, presumably due to interactions between trichloroethylene and neuronal membranes. 

A large degree of variation is apparent in retention rates for americium in the liver among various animal species (Durbin 1973), as indicated by measured or estimated liver clearance half-times of approximately 5-16 days in rats, 152 days in baboons, 1-10 years in dogs, and 10 years in Chinese hamsters. A liver clearance half-time of 2 years has been estimated for humans (Griffith et al. 1983). Refer to Section 3.5.1 for information regarding toxicokinetic mechanisms that may play a role in interspecies differences in liver retention of americium. 

Significant interspecies differences are apparent regarding liver retention rates of absorbed americium (Durbin 1973 Griffith et al. 1983) (see Sections 3.4.2.4 and 3.5.1 for more detailed information). 

However, no data were located to indicate significant interspecies differences in health effects associated with exposure to americium. 

Data for lead effects on mammalian wildlife are scarce. Shore (1995) indicates that lead residues in soils could successfully predict lead concentrations in kidneys and livers of wood mice and field voles however, this could not be demonstrated for shrews. In view of the large interspecies differences in lead responses reported for domestic livestock and laboratory populations of small animals (Table 4.9), more research is needed to determine if lead criteria for these groups are applicable to sensitive species of mammalian wildlife. 

Silver occurs naturally in several oxidation states, the most common being elemental silver (Ag°) and the monovalent ion (Ag+). Soluble silver salts are, in general, more toxic than insoluble salts. In natural waters, the soluble monovalent species is the form of environmental concern. Sorption is the dominant process that controls silver partitioning in water and its movements in soils and sediments. As discussed later, silver enters the animal body through inhalation, ingestion, mucous membranes, and broken skin. The interspecies differences in the ability of animals to accumulate, retain, and eliminate silver are large. Almost all of the total silver intake is usually... 

Hektoen, H., K. Ingebrigtsen, E.M. Brevik, and M. Oehme. 1992. Interspecies differences in tissue distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin between cod (Gadus morhua) and rainbow trout (Oncorhynchus mykiss), Chemosphere 24 581-587. 

Metabolism of fenvalerate proceeds by way of oxidation and hydrolysis to produce metabolites considered pharmacologically inactive or inferior to the parent compound. Insects and fish are extremely susceptible to fenvalerate when compared to mammals and birds. Interspecies differences are associated with rates of metabolism, excretion, absorption, esterase activity, and neurosensitivity. 

Drawbaugh, R.B. and T.C.Marrs. 1987. Interspecies differences in rhodanese (thiosulfate sulfurtransferase, EC 2.8.1.1) activity in liver, kidney and plasma. Comp. Biochem. Physiol. 86B 307-310. 

Drawbaugh RB, Marrs TC. 1987. Interspecies differences in rhodanese (thiosulfate sulfurtransferase,... 

Of course, it is well known that substantial interspecies differences in amino acid and protein needs exist, and that these are genetically determined. It is also notable that there are substantial differences between the maintenance pattern for adults and the growth pattern for infants.24... 

If there are species differences in morphology and physiology between the brains of newborn monkeys, gorillas, chimpanzees, and humans and if these interspecies differences are meaningful with respect to intellectual capacities, how about intraspecies differences in morphology and physiology Is it not probable that they are also meaningful ... 

Although there appears to be no significant species differences in absorption rates for small lipophilic drugs, some interspecies differences are noted with water-soluble drugs absorbed from distal airspaces of in vivo mammalian lungs [112], These species differences have not been systematically studied yet. However, some marked differences were reported for protein absorption rates... 

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