Title: The phenomena of anuran metamorphosis. III. The development of the thyroid gland
Abstract: Abstract This paper presents a study of the growth and histological development of the thyroid in three species of frogs, the small Pseudacris triseriata, the large Rana catesbeiana and the intermediate Rana palustris. It was found that the history of the gland in relation to metamorphosis is essentially the same in all. Previous to metamorphosis the gland is small, and the cells very poor in cytoplasm. At the beginning of metamorphosis (i.e., rapid hind leg growth) the thyroid shows a marked acceleration of growth and activity, which continues and reaches a peak at the time of the emergence of the front legs. Late in metamorphosis a regression occurs. The conclusion is drawn that there is a rising concentration of thyroid hormone during the course of metamorphosis. The author has previously shown that such a rising concentration will induce the normal pattern as to sequence and time spacing of metamorphic events. The beginning of metamorphosis is conceived as dependent upon the time of stimulation of the thyroid and the pattern of its subsequent continuance as dependent upon the pattern of response of this gland.
Publication Year: 1936
Publication Date: 1936-03-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 40
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