[Histological observations on the structural changes in rat lacrimal gland by oral administration of lactoferrin]

The purpose of this study was to clarify the influence of enteric-coated lactoferrin (LF) on the secretory function of rat lacrimal secretory gland by using light and electron microscope. The results were as follows. 1) Both A and B granules were observed in lacrimal gland cells in all groups (control groups of young and aged rats, and LF-intake group of aged rat). However, the difference in size and distribution of B granules was determined among different groups. 2) In the control group of young rat, numerous B granules and well-developed cell organelles were observed. On the other hand, a small number of large B granules and undeveloped cell organelles were recognized in the control group of aged rat. 3) In the LF-intake group of aged rat, a large number of large B granules and well developed cell organelles showed similar features to those in the control group of young rat. 4) Large B granules were supposed to be the secretory granules in the final secretory stage. 5) Taken together, it was suggested that the enteric-coated lactoferrin (LF) might promote the secretory function of lacrimal gland cells in aged rat, resulting in the formation of numerous B granules.