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TRH transport to rat milk
Endocrinologia Experimentalis
|October 1, 1983
Summary
Maternal milk contains biologically active thyrotropin-releasing hormone (TRH) that influences TSH secretion and thyroid hormone levels in neonatal rat pups. This neurohormone is transferred from maternal plasma to milk, remaining unaltered and active.
Area of Science:
- Endocrinology
- Neonatal Physiology
Background:
- Neonatal rats exhibit unique TRH-related features, including lack of hypothalamic control over pituitary TSH secretion and resistance to plasma TRH degradation.
- TRH is present in the upper gastrointestinal tract, with duodenal contractility linked to suckling.
Purpose of the Study:
- To investigate the role of exogenous TRH from maternal milk in neonatal rat development.
- To determine if TRH is transferred from maternal circulation to milk in a biologically active form.
Main Methods:
- Administration of TRH to lactating rats and analysis of serum TSH, pituitary TSH, and plasma T4 in pups.
- Intravenous administration of 3H-TRH to lactating rats, with subsequent measurement of radioactivity in plasma and milk.
- Chromatographic and electrophoretic analysis, along with antibody precipitation, to confirm the presence and integrity of 3H-TRH in milk and pup gastric contents.
Main Results:
- TRH injections in lactating rats increased serum TSH and decreased pituitary TSH in pups.
- TRH administration prevented a decrease in plasma T4 in pups of thyroidectomized mothers.
- 3H-TRH was transferred to milk, remaining unaltered and biologically active, with lower degradation activity in milk compared to plasma.
Conclusions:
- TRH is transported from maternal plasma to milk in a unidirectional manner.
- The neurohormone TRH is transferred to rat milk in a biologically active form, impacting neonatal physiology.