The unique toxicity of NRB has been determined by performing animal experiments by using several species of rodents. The toxic dose was orally administered. In the table the defined LD50 data illustrate the compound’s specific toxicity. Rats, particularly the female species, experience even after administration of a small amount of NRB the effects of the toxin. NRB is toxic to guinea pigs and mouse either, but to a lesser extent. There is no reliable information available about LD50 values in humans. Although NRB is a rodenticide, and especially toxic for brown rats, human beings could be exposed to NRB through inhalation and dermal contact. Exposure Acute toxic level Oral LD50 (mg/kg) * Rat (male) 15 * Rat (female) 5 * Guinea pig 620 * Mouse 2250 Acute toxicity studies in rats A lethal dose of NRB to rats causes behavioural changes which look a lot like the signs associated to cyanide toxicity. The first indications of the NRB toxicity present themselves about ten minutes after administration. At first the rats start showing signs of increased motor activity and incoordination. Subsequently, the rats' hind extremities weaken and become ashen. Their breathing begins to be laboured and within a short period of time the rats suffer from series of convulsive movements. The spasm is followed by death, which occurs within 30 minutes in albino laboratory rats and with two hours in wild animals. After examining isolated rat hearts in Langendorff preparations, a frequent in vitro technique, NRB also turned out to cause severe species-selective toxic effects on rat heart. 2-10 µg NRB had been injected into the coronary vessel which resulted in a reduction of blood flow, attended with decreased cardiac contraction and a decreased heart rate. The rat hearts started beating quite irregularly. These irreversible effects weren't marked in the heart muscle (myocardium) as perhaps expected, but straight in the coronary arteries. Additionally, it was confirmed that rats which were subjected to NRB treatment suffered from hyperventilation followed by cardiovascular effects. Recent studies present NRB's ability to activate the mitochondrial permeability transition pore (MPTP) in isolated rat preparations. Cell apoptosis and necrosis are (amongst other things) regulated by MPT pores. It is understandable that such an abnormity in the mitochondrial membranes bring about issues in the cellular metabolism of the poisoned animal. Toxicity studies in mammals and birds The members of the genus Rattus are highly sensitive to NRB, but other animals experience no toxic effects. Upon closer examination a 1000 mg/kg dose of<unk>  didn’t bring forth any toxic signs when orally administered to cats, chickens, dogs, monkeys, mice, swine or birds. This has been confirmed in the table below. So it is safe to say that NRB is relatively harmless to nonrat species.
Norbormide
Nandrolone caproate
Nandrolone
Norethandrolone
Nandrolone hydrogen succinate
Nandrolone propionate
Nandrolone sulfate
Oxandrolone