Objective: To determine the effects of dietary carrots and retinoic acid on P secretion in the in vitro perfused rabbit ovary.Design: Controlled experiment.Setting: Laboratory.Subjects: Sexually mature New Zealand white rabbits.Intervention(s): Experiments were done in vitro using an isolated rabbit ovarian perfusion system after acute feeding of carrots or with in vitro exposure to retinoic acid.Main Outcome Measure(s): Progesterone and E-2 were measured in aliquots taken from arterial and venous cannulas.Result(s): Progesterone secretion during the in vitro perfusion of six ovaries is significantly diminished after the acute feeding of carrots. Human chorionic gonadotropin-induced P secretion also is significantly reduced, Progesterone secretion during in vitro perfusion on day 1 of pseudopregnancy was significantly increased in the perfusate samples from ovaries taken from rabbits not acutely fed carrots but that were exposed to retinoic acid. Progesterone secretion was increased but; only marginally significant on day 11 of pseudopregnancy in perfusate samples from ovaries exposed to retinoic acid.Conclusion(s): Rabbit ovarian P secretion may be modified by carrots and carotene metabolites. This effect on steroid secretion may contribute to the relationship between hypercarotenemia and alterations in menstrual function. (C) 1997 by American Society for Reproductive Medicine.