Materials / Reagents Required :

            10 % Neutral Buffered Formalin (NBF), Davidson’s fluid (1 litre), Modified Davidson’s fluid (1 litre), Normal saline (10 litre), 70 % Ethanol (1 litre), different sizes of scissors, forceps, scalpel, spatula, bone cutter, cardboard paper, etc.

Safety Precautions :

            Protective equipments including laboratory coats, gloves, apron, etc., should be worn during euthanasia, necropsy as well as during the preparation of the solutions.

Anatomy:

• The pituitary gland is closely associated with the ventral surface of the brain and is studied, after the brain has been removed from the skull. The pituitary lies within the sellaturcica of the sphenoid bone and receives blood via the posterior and anterior hypophyseal arteries, which originate from the internal carotid arteries.
• The thyroid rat gland is on the ventral surface of the trachea at its anterior end where it joins the larynx. The thyroid gland has two main lobes lying on either side of the midline and joined by a narrow isthmus.  The Parathyroid glands are small and usually difficult to locate. The rat has only one pair which is embedded in the dorsal surface of the thyroid gland.
• The adrenal glands are separate structures, lying just anterior to the kidneys. The adrenal glands are flattened bi-lobed organs located in close proximity to the kidneys They have their own blood supply. The pancreas consists of two functionally and anatomically separate parts.
• The pancreas consists of a main body of the gland that secretes digestive enzymes and the endocrine portion of the gland which secretes hormones into the blood stream. The latter portion of the pancreas consists of many small islets of langerhans, scattered throughout the gland.
• In the male, the testes that contain glandular interstitial tissue in addition to the sperm producing seminiferous tubules are located inside the scrotum on the ventral side of the body beneath the base of the tail. In the female, the pair ovaries that contain follicles are present in the abdominal cavity and are connected to the  uterus through the oviducts.

Collection of the endocrine glands :

• After induction of anaesthesia/euthanasia, the fur of the animal shall be moistened with alcohol to prevent the fur from getting adhered into the tissue samples. Normal saline shall be kept ready during the necropsy to keep the lungs moist.
• The thoracic and abdominal cavities shall be opened with a median incision starting from the just above the penis in male rat and just above the urethral orifice in the female rat up to the neck region. The adrenal gland present above the kidneys on the abdominal wall shall be collected first as they may be easily lost.
• The testes and epididymis shall be exposed by applying gentle pressure over the scrotal sac, separated and dissected out carefully. The female reproduce system including the ovaries, uterus and vagina shall be dissected out carefully and fixed. The ovaries shall be isolated and kept in tissue cassettes as they may be easily lost and then, are fixed.
• Thoracic viscera including trachea, thyroid gland, para-thyroid gland shall be removed. The pituitary gland shall be removed along with its underlying skull bones and shall be fixed as such. The gland shall be removed from the bones after fixation