Ultrastructure of deer and roe-buck thyroid

Summary

After examining the ultrastructure of thyroid during embryogenesis and hyperplasia as well as the glands of deer with bad antlers quality and those of roe-bucks the following results were obtained:

• 1. The characteristic differences between the follicular cells of hyperplastic thyroid and those of fetus are:

  • a) When the synthetic and secretory pathways are prevalent nucleoli varied more in size and in the quantity of the ribosomal units; the granular endoplasmic reticulum was more irregularly organized; the cavities of granular endoplasmic reticulum were full with more osmiophilic substances and their content is in direct connection with colloid droplets. There are more microvesicles between the Golgi and apical cell surface, and the size and the matrix density of mitochondria were more variable; microvilli are more irregular and apical cell protrusions enclosing the luminal colloid were noticed. Intracellular droplets originate as a result of synthetic or reapsorptive processes.

  • b) When the suppression of synthetic and secretory processes was clearly expressed nucleoli, endoplasmic granular reticulum, Golgi zones and mitochondria were in various stages of involution; the number and size of irregular heterogenous dense bodies and globules were increased, whereas the number and size of microvesicles and microvilli were reduced.

• 2. The thyroid follicular cells of deer with bad antlers quality show very strong degradative changes of all cell organelles and an increase of multivesicular and heterogenous dense bodies. It seems that most of dense bodies belong to the lysosomal system.

• 3. The follicular cells of the examined roe-buck thyroid had round and oval dense bodies with the smaller ones of higher density; polysomes were in groups, while the granular endoplasmic reticulum, Golgi and mitochondria were extremely reduced and in various stages of degradation.

• 4. Parafollicular cells are formed during early stage of the follicle formation in fetal as well as in the hyperplastic thyroid and there is similarity in their ultrastructure. The results support our opinion on the role of thyroid and the close relationship between the follicular and parafollicular cells respectively with both deer sexual cycle and behaviour as well as with the development and the antlers quality.