GLP and The USFDA
The United States FDA has rules for GLP in 21CFR58. Preclinical trials on animals in the United States of America use these rules prior to clinical research in humans.
Research in the US not conducted under these restrictions or research done outside US not conducted according to the OECD Guidelines (or FDA rules) might be inadmissible in support of a New Drug Application in the US.
Read more about this topic: Good Laboratory Practice