There is little recent information on the developmental regulation of SP-D expression. In general, SP-D increases rapidly late in gestation [97] [98] [99] [100] . The production of SP-D increases during the culture of fetal lung explants, and expression can be increased with glucocorticoids [98, 100, 101] . The exposure of fetal rats to glucocorticoids in vivo leads to precocious expression with increased numbers of SP-D-expressing cells and increased cellular levels of SP-D message [98, 101, 102] .