Figure 1.

(A) Connexin expression pattern in adrenal gland dependent of zonation, being the highest in zona reticularis. (B) Schematic review of gap junction structure; a connexin is a protein with four transmembrane domains, two extracellular loops and one intracellular loop, and intracellular N- and C-terminal tails. Six connexins form a hemichannel or connexon, and two connexons form a gap junction. * ZR > ZF >> ZG. Abbreviations: Cx—connexin; ZG—zona glomerulosa; ZF—zona fasciculate; and ZR—zona reticularis.