Plasma vitamin A, carotenoids, retinol binding protein (RBP), prealbumin (PA), HDL-and total cholesterol were examined in healthy adult females. Plasma levels of vitamin A and carotene were determined by a spectrophotometric method using trifluoroacetic acid, plasma RBP and PA by single radial immunodiffusion, and HDL-and total cholesterol by enzymatic colorimetry. Vitamin A and carotene mean values resulted as 43.0 +/- 8.2 micrograms/100 ml and 231.9 +/- 69.0 micrograms/100 ml, respectively. RBP and PA values averaged as 4.2 +/- 1.1 mg/100 ml and 29.4 +/- 6.1 mg/100 ml, respectively; whereas HDL-and total cholesterol were 179 +/- 16 mg/100 ml and 57 +/- 8 mg/100 ml. Vitamin A plasma levels were shown to be significantly related (P less than 0.01) to RBP and PA, but not to the other parameters examined (carotene, HDL-and total cholesterol).