Vitamin A and beta-carotene in bovine and porcine plasma, liver, corpora lutea, and follicular fluid.

Bovine and porcine blood plasma, liver, corpora lutea, and follicular fluid were obtained from local abattoirs for study of distribution of vitamin A and beta-carotene. Retinol, retinyl esters, and beta-carotene were separated on alumina columns and subjected also to thin-layer chromatography. Retinol and retinyl esters were in corpora lutea and follicular fluid of both species. Concentrations of beta-carotene were high in bovine plasma, corpus luteum, and follicular fluid. In contrast, beta-carotene was lower in porcine tissues. Retinol, retinyl esters, and beta-carotene were closely correlated in bovine follicular fluid and blood plasma; however, correlations between bovine plasma and corpora lutea were not significant except for retinol. Only porcine retinol was closely correlated with plasma and follicular fluid, whereas correlations were nonsignificant between plasma and corpora lutea retinol, retinyl esters, and beta-carotene. Further studies, therefore, are needed to elucidate the physiological role of vitamin A and beta-carotene in regulating ovarian functions.