The effect of long-term administration of various doses of hCG or TP on the thyroid of 33 adult male rabbits of pure Bouscat breed were histologically and stereologically investigated. The thyroid activity exhibited a dose-related increase in rabbits injected with hCG. A marked progressive decrease in the follicular and colloidal volumes as well as gradient increase in the number of follicles per mm, volume of the follicular cell, nuclear volume and stromal vas cularization were observed in the thyroids of rabbits treated with hCG.
The low and high doses of testosterone propinate (TP) induced morphological signs of higher glandular activity without any significant difference between the doses of TP.