Laminin Isoforms in Fetal and Adult Human Adrenal Cortex

Abstract

Laminin has been proposed to influence the function of human adrenal cortex. We have studied the distribution of laminin (Ln) chains using immunofluorescence in human fetal and adult adrenal cortex. In the fetal gland Ln α2- and α5-chains were weakly expressed in the definitive zone, whereas Ln α4-, β1-, and γ1-chains occurred around vessels. In the adult gland, Ln α2-, α5-, and γ1-chains were found in epithelial basement membranes (BM) in all cortical zones, Ln α4-chain in vessels, Ln β1-chain in outer zone, and Ln β2-chain in the two inner zones of the cortex, respectively. Among the integrins in adult gland, integrin α3-subunit was confined to basal surfaces of cortical cells, α6 to vessels, α1 to the stroma, and α2 diffusely to epithelial cells. Lutheran glycoprotein and dystroglycan occurred in the fetal gland diffusely in the definitive zone and throughout the epithelium in the adult. The isoform composition of BM of the adult adrenal gland is distinct, with Ln-2 and -10 in BM of the outer zone and Ln-4 and -11 in BM of the two inner zones. The results suggest that integrin α 3β1 and Lutheran are candidate receptors for Ln-10 and -11, whereas dystroglycan probably binds Ln-2 and -4.