INVESTIGATIONS OF THE THYROID OF DEER AND ROE-BUCKS

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Abstract
In the thyroid of sexually mature stags cyclic changes occur. In the course of winter the gland is very hyperemic and the epithelium of the follicles is low prismatic. In the course of spring time the height of the epithelium increases as well as the quantity of colloid granules in the cytoplasm. The increase of the epithelium height continues during the period of growth and antler ossification. After the shedding of the velvet, the quantity of granules in the cytoplasm of the glandular cells decreases, the vacuoles are more frequent and the quantity of RNA and affinity towards the basic dyes is weaker. After mating, the height and structure of the glandular cells point to the decrease of the thyroid activity. Parafollicular cells are very frequent. A big nucleolus in the nuclei of these cells and a basophilic cytoplasm point to an active role of these cells. The glands of the roebuck are of smaller weight (on the average 1.1 g), the epithelium is lower, the quantity of PAS positive granules in the cytoplasm is larger and the occurrence of pigment granules more frequent. The structure and thyroid activity of the deer and the roebuck change depending on the season, and the changes are closely connected with the properties of the hypothalamohypophyseal system of these monoestric animals. The course of development and quality of the antlers depend on the thyroid capability to respond to the stimuli of interior or outward environment. The antler quality is so much the worse according to the changes in the structure and function of the thyroid.