Lipid droplet accumulation in the exocrine glands of the newborn rat.

Exocrine glands including the submandibular gland, sublingual gland, exocrine pancreas and exorbital lacrimal gland of newborn rats aged 0 to 14 days were examined morphologically, and the following results on the accumulation of lipid droplets were obtained. Lipid droplets tended to localize in secretory cells, especially in their basal cytoplasm. The degree of lipid droplet accumulation varied with the type of exocrine gland. There were large accumulations in the sublingual gland, submandibular gland, and exocrine pancreas, but accumulations were small in the exorbital lacrimal gland. No difference in lipid droplet accumulation was recognized between the 2 types of secretory cells in the sublingual gland. The accumulation of lipid droplets peaked 24-48 hours after birth in the sublingual gland, submandibular gland and exocrine pancreas, but this peak was not clearly observed in the exorbital lacrimal gland. In the group of newborn rats separated from their mothers and therefore not suckled, no lipid droplets were observed in any gland, suggesting a close relationship between lipid droplet accumulation and suckling.