SEASONAL-VARIATION IN THE SECRETORY ACTIVITY OF THE SUBCOMMISSURAL ORGAN (SCO) OF REPTILES

Seasonal variations in the secretory activity of the subcommissural or gan (SCO) of snakes and turtles was studied by immunocytochemistry, le ctins, and electron microscopy. In animals sacrificed in summer, immun oreactive material, mostly devoid of sialic acid, occupied the whole c ytoplasm. Cells showed many distended cisternae of rough endoplasmic r eticulum and secretory granules. In animals sacrificed in winter, patc hes of immunoreactive sialic acid-rich material occupied the apical cy toplasm. Cells lacked distended cisternae and the secretory granules f ormed clusters. These results suggest a decreased synthesis and releas e of secretory material in the SCO of lethargic reptiles.