Histology and morphology of �the Harderian gland in house mouse and its probable role in relation between mother and littermates ﻫﻴﺴﺘﻮﻟﻮژي و ﻣﻮرﻓﻮﻟﻮژيHarderian glandدر ﻣﻮش ﺧﺎﻧگﻲ و ﻧﻘﺶ اﺣﺘﻤﺎﻟﻲ ﻏﺪه ﻣﺰﺑﻮر در ارﺗﺒﺎط ﻣﺎﺑﻴﻦ ﻣﺎدر و زاده

In order to study morphology and histology of the Harderian gland in house mouse,� the animals were killed in different days of their life and the Harderian glands of the left and the right eyes were dissected. Harderian glands are horse - shoe shaped and lobulated . It is located in the posterior region of the eye ball. Its color as observed in saline solution is white-grey or pinkish – grey. The Harderian glands and the animals were weighed at every occasion of killing to find out the ratio. The average ratio of the Harderian gland to body weight was approximately 1:2500. Also using paraffin embedding technique and the staining method of Hematoxylin and Eosin, the histology of the Harderian gland was studied under light microscope. Harderian glands are alveolar glands with columnar cells having round nuclei at the base. The main secretory product of the gland is lipid inside the vacuoles that have been discharged and washed away during the process of staining. The presence of the empty vacuoles supports the mentioned idea. Considering the size of the lipid vacuoles, 3 types of secretory epithelial cells were observed in house mouse Harderian gland . Apical secretory activity , in addition to the presence of secretion in alveolar ducts (lumens), represent exocrine mechanism. Although this activity is continual, it undergoes fluctuations. The signs to these fluctuations could be observed by changing the size of alveolus and lumens, transformation of cells and presence of cell debris in alveolar ducts. Also presence of blood vessels around alveoles may indicate endocrine mechanism. Factors involved in probable fluctuations on the one hand, and the idea of endocrine secretions , on the other hand should be determined in future studies. Regarding the probable role of pheromonal secretion in existing relationship between mother and the littermates, the reaction of littermates to the crushed Harderian glands of their mother was studied. The seeking movement of the head of the littermates may indicate chemosensory reactions of the olfactory systems (mainly vomeronasal system )to the crushed Harderian glands of the mother . It may also indicate to a probable role in initiating communication between mother and littermates.