Related Experiment Videos
Damped oscillations in serum thyroid hormone levels of normal newborn infants
Insights
Newborns experience hormonal oscillations after birth. The study reveals periodic fluctuations in thyroid hormones (T4, T3) and TSH during the first five days of life, indicating the body
Area of Science:
- Endocrinology
- Neonatal Physiology
Background:
- The transition to an extrauterine environment significantly stimulates the hypothalamic-pituitary-thyroid (HPT) axis in newborns.
- Reestablishing pituitary-thyroid equilibrium is crucial following this initial perturbation.
Purpose of the Study:
- To investigate the dynamic changes and oscillatory patterns in thyroid hormone concentrations during early neonatal life.
- To analyze the reequilibration process of the HPT axis in healthy newborns.
Main Methods:
- Serum concentrations of thyroxine (T4), triiodothyronine (T3), and thyroid-stimulating hormone (TSH) were measured using radioimmunoassay (RIA).
- Data from 440 healthy newborns (birth to 236 hours) were analyzed using nonlinear curve-fitting procedures.
- Danziger and Elmergreen's equations were applied to assess oscillatory behavior in hormone concentrations over time.
Main Results:
- Significant oscillations were observed in serum T4, T3, and TSH concentrations within the first five days of life.
- The approximate period of these hormonal oscillations was found to be 16 hours.
- Hormone concentration patterns showed TSH oscillations preceding T4, which in turn preceded T3 oscillations.
Conclusions:
- Disturbances in the HPT axis equilibrium are followed by periodic hormonal oscillations in newborns.
- These oscillations decrease in amplitude as the negative feedback system facilitates the establishment of a new equilibrium.
- The findings highlight the dynamic nature of thyroid axis regulation during the neonatal period.
Abstract:
Exposure to the extrauterine environment is associated with marked stimulation of the hypothalamic-pituitary-thyroid system after which, pituitary-thyroid equilibrium must be reestablished. This marked endogenous perturbation offers the opportunity to study the manner in which the pituitary-thyroid axis is reequilibrated. T4, T3 and TSH concentrations have been measured by RIA in sera from 440 healthy newborn infants, whose ages ranged from birth to 236 h. Results were analyzed by nonlinear curve-fitting procedures to assess the changes in mean hormone concentrations with age (t). Equations have been derived by Danziger and Elmergreen to allow assessment of oscillatory behavior during hormone equilibration. Applying these equations to the present data, we observed the presence of an oscillatory cosine term in the equation for each hormone. This indicates significant oscillations in serum T4, T3, and TSH concentrations during the first 5 days of life. The period of the oscillations approximates 16 h. The oscillations in T4, lag 1/2 to 3/4 cycle behind TSH; T3 lags behind T4. Thus, disturbances in hypothalamic-pituitary-thyroid equilibrium seem to be followed by periodic oscillations in hormone concentrations; these oscillations decrease in amplitude as the negative feedback system establishes new equilibrium conditions.