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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2006-1-13
pubmed:abstractText
The carcinogenic potential of nelfinavir mesylate (nelfinavir) was evaluated in a 2-year oral (gavage) study on Sprague-Dawley rats at dose levels of 0 (control), 0 (vehicle control), 100, 300 and 1000 mg/kg per day. At the end of the treatment, increased incidences of thyroid follicular cell hyperplasia and neoplasms were observed at 300 (males) and 1000 mg/kg per day (both sexes). There were no other treatment-related effects and no tumors at other sites. Results from previous studies indicated a number of effects in the liver and thyroid, as well as metabolic profiles that suggested nelfinavir might cause thyroid hyperplasia/neoplasia secondary to hormone imbalance by altering thyroid hormone disposition. To investigate this hypothesis, the effects of nelfinavir on gene expression in rat hepatocytes and liver slices (in vitro), thyroxine plasma clearance, and thyroid gland function were evaluated. Compared to controls, gene expression analyses demonstrated an increased expression of glucuronyltransferase (UDPGT) and CYP450 3A1 in nelfinavir-treated rat hepatocytes and liver slices. In rats treated with nelfinavir (1000 mg/kg per day) for 4 weeks, liver weights and centrilobular hepatocellular hypertrophy were increased and minimal to mild diffuse thyroid follicular cell hypertrophy and follicular cell hyperplasia were evident in the thyroid gland. Thyroid-stimulating hormone (TSH) levels were significantly increased (three-fold), while tri-iodothyronine (T3)/tetra-iodothyronine (T4) and reverse T3(rT3) levels were unchanged, indicating that a compensated state to maintain homeostasis of T3/T4 had been achieved. Plasma 125I-thyroxine clearance was increased and the plasma thyroxine AUC0-48 was decreased (24%) compared to control. In conclusion, these data indicate that thyroid neoplasms observed in the nelfinavir-treated rats were secondary to thyroid hormone imbalance. Increased thyroxine clearance contributes to the effects of nelfinavir on thyroid gland function and is probably a result of UDPGT induction that leads to elevated TSH levels in the rat and eventual thyroid neoplasia. These results are consistent with a well-recognized rat-specific mechanism for thyroid neoplasms.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0960-3271
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
643-54
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed-meshheading:16408618-Adenocarcinoma, Follicular, pubmed-meshheading:16408618-Administration, Oral, pubmed-meshheading:16408618-Animals, pubmed-meshheading:16408618-Aryl Hydrocarbon Hydroxylases, pubmed-meshheading:16408618-Carcinogenicity Tests, pubmed-meshheading:16408618-Cell Survival, pubmed-meshheading:16408618-Cells, Cultured, pubmed-meshheading:16408618-Cytochrome P-450 CYP3A, pubmed-meshheading:16408618-Dose-Response Relationship, Drug, pubmed-meshheading:16408618-Female, pubmed-meshheading:16408618-Gene Expression, pubmed-meshheading:16408618-Glucuronosyltransferase, pubmed-meshheading:16408618-HIV Protease Inhibitors, pubmed-meshheading:16408618-Hepatocytes, pubmed-meshheading:16408618-Hyperplasia, pubmed-meshheading:16408618-Longevity, pubmed-meshheading:16408618-Male, pubmed-meshheading:16408618-Nelfinavir, pubmed-meshheading:16408618-RNA, Messenger, pubmed-meshheading:16408618-Rats, pubmed-meshheading:16408618-Rats, Sprague-Dawley, pubmed-meshheading:16408618-Species Specificity, pubmed-meshheading:16408618-Thyroid Gland, pubmed-meshheading:16408618-Thyroid Hormones, pubmed-meshheading:16408618-Thyroid Neoplasms, pubmed-meshheading:16408618-Thyroxine
pubmed:year
2005
pubmed:articleTitle
Increase in thyroid follicular cell tumors in nelfinavir-treated rats observed in a 2-year carcinogenicity study is consistent with a rat-specific mechanism of thyroid neoplasia.
pubmed:affiliation
Pfizer Global Research and Development, San Diego, CA 92121, USA. leighann.burns@pfizer.com
pubmed:publicationType
Journal Article