Uptake of beta-carotene by ovarian and uterine tissues and effects on steroidogenesis during the estrous cycle in cats

Objectives-To determine uptake of beta -carotene by ovarian and uterine tis sues and influence of dietary beta -carotene on steroidogenesis and product ion of uterine protein during the estrous cycle in cats. Animals-56 female cats. Procedure-Cats were fed diets containing 0, 0.4, 2, or 10 mg of beta -carot ene daily for 8 weeks prior to detection of estrus. At time of observed est rus, all cats were manually induced to ovulate. Blood samples were obtained at estrus and every 2 days until day 14 after ovulation. On that day, cats underwent laparotomy, and the ovaries and uterus were removed. Uterine con tents were flushed, and luteal and endometrial tissues were obtained. Results-Concentrations of beta -carotene in plasma and luteal and endometri al tissues increased in a dose-dependent manner. Concentrations of plasma p rogesterone were higher between days 6 and 10 after ovulation in cats fed d iets containing beta -carotene and continued to increase through day 14 aft er ovulation in cats fed a diet containing 10 mg of beta -carotene. Plasma concentration of estradiol-17 beta also was higher between days 0 and 4 aft er ovulation in cats fed diets containing beta -carotene. Cats fed a diet c ontaining 10 mg of beta -carotene had the highest plasma estradiol concentr ation. Total uterine protein concentration was higher in cats fed beta -car otene, compared with values for cats fed an unsupplemented diet. Conclusion and Clinical Relevance-Cats readily absorb beta -carotene. Incre ased concentrations of progesterone, estradiol, and uterine protein may pro vide more optimal ovarian function or a better uterine environment for embr yonic survival and development.