SEX DIFFERENCE IN THE EXPRESSION OF LAMININ-LIKE PROTEIN IN THE RAT ANTERIOR PITUITARY

Anti-laminin-positive gonadotrophs in the anterior pituitary were immunocytochemically examined in rats of either sex at various ages. In the male, the ratio of the cell number of the positive cells to that of gonadotrophs gradually increased until day 60 when a plateau (10∼80%) was reached. In the female, on the contrary, the ratio reached the maximal level (∼60%) at day 30, but then suddenly decreased within 10 days (∼5%). The results suggest that the level of laminin-like protein relates to the cyclic gonadotropin secretion accompanied by the estrous cycle in the female