| Abstract: | The intensity of motor activity and the serum level of protein-bound iodine (PBI) were investigated in 62 puppies aged from 1 to 12 months. During the first 4 months of life a parallel increase in motor activity and PBI of the puppies was observed. The increase in motor activity of puppies between the ages of 7 and 9 months was not accompanied by any increase in PBI. In hypothyroidism caused by methimazole in puppies aged 1 and 3 months increased motor activity was observed, whereas in animals aged 7 months it was reduced. A higher intensity of motor activity than in the control animals also was observed 1 month after the operation in puppies thyroidectomized at the ages of 1 and 3.5 months. The activity of puppies thyroidectomized at the age of 1 month was sharply reduced 2–4 months after the operation. In dogs thyroidectomized at the ages of 7.5 and 11.5 months, reduced activity was observed as early as 1 month after the operation. The data showing opposite effects of thyroid hormones on the behavior of puppies at different ages point to a complex relationship between motor activity and thyroid function.Laboratory of Comparative Ontogeny of Higher Nervous Activity, I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Chernigovskii.) Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 87, No. 2, pp. 108–110, February, 1979. |
