Distribution of prolactin in selected rat organs and tissues.

A single dose of 25 microg prolactin (PRL)/kg of rat body weight was administered to rats subcutaneously. At 1, 2, 3, 4 and 5 h after the injection, selected organs and tissues were taken for analysis. It was found that 1 h after administration, the highest amount of PRL accumulated in the milk (lactiferous) gland, the blood, the ovaries, the pituitary and the liver. Over time, the prolactin content in the selected organs and tissues decreased. PRL is selectively captured by the milk gland, the pituitary, the ovaries, the liver and the heart. Based on the value of the organ or tissue capacity index for PRL, the following order was established for the organs and tissues to which the hormone binds: milk gland > blood > pituitary > ovaries > lungs > liver > cranial bone > spleen > heart > kidneys > muscular tissue > adrenals > adipose tissue > brain.