title: The guinea pig as an animal model for developmental and reproductive toxicology studies.
abstract: BACKGROUND
  Regulatory guidelines for developmental and reproductive toxicology (DART) studies require selection of "relevant" animal models as determined by kinetic, pharmacological, and toxicological data. Traditionally, rats, mice, and rabbits are the preferred animal models for these studies. However, for test articles that are pharmacologically inactive in the traditional animal models, the guinea pig may be a viable option. This choice should not be made lightly, as guinea pigs have many disadvantages compared to the traditional species, including limited historical control data, variability in pregnancy rates, small and variable litter size, long gestation, relative maturity at birth, and difficulty in dosing and breeding.
  
  
  METHODS
  This report describes methods for using guinea pigs in DART studies and provides results of positive and negative controls. Standard study designs and animal husbandry methods were modified to allow mating on the postpartum estrus in fertility studies and were used for producing cohorts of pregnant females for developmental studies.
  
  
  RESULTS
  A positive control study with the pregnancy-disrupting agent mifepristone resulted in the anticipated failure of embryo implantation and supported the use of the guinea pig model. Control data for reproductive endpoints collected from 5 studies are presented.
  
  
  CONCLUSIONS
  In cases where the traditional animal models are not relevant, the guinea pig can be used successfully for DART studies.
authors.affiliation: TherImmune Research Corp., Gaithersburg, Maryland, USA. mrocca@amgen.com
authors.forename: Meredith S
authors.initials: MS
authors.lastname: Rocca
authors.forename: Nancy G
authors.initials: NG
authors.lastname: Wehner
mesh_terms: D000019:Abortifacient Agents / Q000633:toxicity; D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D001947:Breeding / Q000379:methods; D010064:Embryo Implantation / Q000187:drug effects; D030762:Estrous Cycle; D005260:Female; D005298:Fertility; D006168:Guinea Pigs / Q000196:embryology* / Q000502:physiology; D008098:Litter Size; D008297:Male; D015735:Mifepristone / Q000633:toxicity; D023421:Models, Animal; D009929:Organ Size / Q000187:drug effects; D010865:Pilot Projects; D011247:Pregnancy; D018873:Pregnancy Rate; D013045:Species Specificity; D013094:Spermatozoa / Q000166:cytology; D014116:Toxicology / Q000379:methods* / Q000592:standards; D014599:Uterus / Q000187:drug effects
chemical_list: D000019:Abortifacient Agents; D015735:Mifepristone