CRF administered to pregnant rats alters offspring behavior and morphology

Pregnant rats injected with 20 micrograms of corticotropin-releasing factor (CRF) from day 14 through 21 gained less weight during gestation than did saline-injected controls. The offspring of CRF-injected females differed from the offspring of control females in several ways: males and females weighed less during the first 2 weeks of life, males had shorter anogenital distances at birth, and males and females emitted more ultrasonic vocalizations during isolation in tests at 6 and 14 days of age. These effects are similar to those that have been observed following exposure of pregnant females to stressors, and provide support for the notion that CRF and/or CRF activation of the hypothalamic-pituitary-adrenal axis mediate effects of gestational stress.