Histological observations on the changes in thyroid activity in the scincid lizard, Mabuya striata, during different phases of tail regeneration
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Date
1977
Authors
Magon, D.K.
Journal Title
Journal ISSN
Volume Title
Publisher
Zoological Society of Southern Africa
Abstract
Measurements of the follicle cells of the thyroid during different phases of regeneration of the tail in the scincid lizard. Mabuya striata. indicate a decrease in thyroid activity during the wound-healing phase and an increase at the end of the blastema phase.
The significance of endocrine secretion of the thyroid has drawn the attention of a number of developmental biologists as the hormone thyroxine brings about various physiological changes during anuran metamorphosis. The regenerative power of these amphibians gradually diminishes as metamorphosis advances. It may be absent in the fully metamorphosed animals (Rose 1964), or sometimes restricted to wound healing or to the formation of a hypermorphic cartiJaginous spike (Richards et oJ. 1975). Further, PawlowskJ (1933), Peadorr (1953) and Schotte & Washburn (1954) showed that thyroidectomy, treatment with thiourea, or increased doses of thyroxine hinder amphibian regeneration. Nevertheless, Tassava (1969) and Bromley & Thornton (1974) presented data indicating that prolactin when present with thyroxine promotes limb regeneration. Thus these reports suggest some possible relationship of thyroxine to metamorphic changes and capacity for regeneration in the amphibians. However, the role of thyroxine and other thyroid secretions in regeneration of reptiles is still unknown. The following communication describes an attempt to examine histological differences in the thyroid activity in the normal scincid lizard, Mabuya striata. and those showing different stages of tail regeneration, with a view to assessing the role of thyroid secretion in the regenerative processes of this reptile
Description
Keywords
Endocrine secretion, Hormone thyroxine, Anuran metamorphosis, Hypermorphic cartilaginous spike, Prolactin, Epithelial cells of follicle, Growth phases, Metabolic activities, Hyperthyroidism, Wound-healing
Citation
African Zoology Volume 12 Issue 2, Pages 389-392