Abstract
Summary
Mature male fowls were divided into 4 groups of equal TSR. One group served as controls whereas the other 3 groups were injected daily with 0.5 mg tapazole/100 g bw/day for 30, 60 and 90 days. The mean wet thyroid gland weight of the control group was 134.8 mg. After 30 days, the thyroid weight increased 66.8%, after 60 days, the increase was 187.9%, and after 90 days the increased weight was 136.5% above the controls. The determination of the total DNA of each group of thyroid glands indicated the extent of cell multiplication involved and from these data it was possible to estimate the proportion of the weight increase which was due to cell multiplication and the increase due to cell size.
After 30 days the cell multiplication accounted for 68% and cell size for 32% of the increase, after 60 days 57% to cell multiplication and 43% to cell size and after 90 days 42% due to cell multiplication and 58% due to cell size.
Get full access to this article
View all access options for this article.