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Lung development under the influence of thiourea and L-thyroxine. Retarding and toxic effects of thiourea
J Wittmann1, A Steib, H G Liebich
1Institut für Physiologie, Physiologische Chemie und Ernährungsphysiologie, Universität München, FRG.
Insights
Thiourea and L-thyroxine treatments in chick embryos affected hatching and lung development. L-thyroxine accelerated hatching and lung maturation, while thiourea delayed hatching and impaired lung development, suggesting toxicity.
Area of Science:
- Embryology
- Developmental Biology
- Endocrinology
Background:
- Chick embryo development is a model for studying physiological changes during incubation.
- Hatching is a critical developmental milestone influenced by hormonal and environmental factors.
- Pulmonary development and fluid absorption are crucial for successful hatching.
Purpose of the Study:
- To investigate the effects of thiourea and L-thyroxine on chick embryo hatching and pulmonary development.
- To determine if observed changes in lung structure and fluid absorption are due to developmental retardation or toxic effects.
Main Methods:
- Chick embryos were treated on day 17 of incubation with thiourea or L-thyroxine.
- Hatching time, pulmonary structure, circulation, and parabronchial liquid absorption were assessed.
Main Results:
- L-thyroxine accelerated hatching, advanced pulmonary structure and circulation, and promoted parabronchial liquid absorption.
- Thiourea delayed hatching, suppressed parabronchial structure formation, and caused parabronchial liquid accumulation.
- These effects suggest thiourea's impact is a toxic effect rather than a developmental delay.
Conclusions:
- Hormonal manipulation with L-thyroxine can advance embryonic development, including pulmonary maturation.
- Thiourea exhibits toxic effects on chick embryo development, specifically impairing lung formation and fluid dynamics.
- The study highlights the differential impact of exogenous substances on embryonic development and hatching success.
Abstract:
Chick embryos were treated on day 17 of incubation with 32.8 mumol thiourea or 18.9 nmol L-thyroxine. As was already known from previous studies, hatching was delayed and accelerated, respectively, under these conditions. The premature induction of hatching by L-thyroxine was accompanied by an advanced development of the pulmonary structure and of the circulation and by a premature absorption of the parabronchial liquid. Thiourea exerted an opposite effect on these parameters. In several cases the structural formation of the parabronchii was suppressed after treatment with thiourea. Furthermore, parabronchial liquid accumulated in those embryos, the hatching of which was suppressed. It is suggested that these changes represent a toxic effect of thiourea rather than a retardation of pulmonary development.