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Insulin antibodies retard and insulin accelerates growth and differentiation in early embryos
Insights
Endogenous insulin is crucial for early embryonic development, regulating growth and differentiation. Blocking insulin in chick embryos caused growth retardation and delayed biochemical maturation, highlighting its vital role.
Area of Science:
- Developmental Biology
- Endocrinology
- Embryology
Background:
- The physiological role of insulin during early embryonic development remains largely unknown.
- Insulin has been detected in unfertilized eggs and early chick embryos prior to pancreatic development.
Purpose of the Study:
- To investigate the role of endogenous insulin in early embryonic growth and differentiation.
- To determine if insulin produced outside the endocrine pancreas influences embryonic development.
Main Methods:
- Chick embryos (2 days old) were treated with anti-insulin antibodies to block endogenous insulin.
- Embryo development, survival rates, and biochemical markers were assessed up to day 5.
- Exogenous insulin was administered to assess its effects on embryonic development.
Main Results:
- Anti-insulin antibody treatment led to increased growth retardation and mortality between days 3-5.
- Survivors of antibody treatment exhibited delayed biochemical maturation, reduced weight, and decreased protein and creatine kinase levels.
- Administration of exogenous insulin promoted embryonic growth and development.
Conclusions:
- Endogenous insulin plays a significant physiological role in regulating early embryonic growth and differentiation.
- These findings suggest a potential function for insulin produced outside the beta cells in embryonic development.
Abstract:
The physiologic function of insulin in early embryonic life is unknown. We have shown that insulin is present in unfertilized eggs and in chick embryos at 2-3 days of development, even before the emergence of the endocrine pancreas. To define insulin's role, we exposed 2-day-old chick embryos to anti-insulin antibodies and followed their development up to day 5. Antibody-treated embryos had a higher rate of growth retardation and death by days 3-5 of embryogenesis, compared with controls. Among the survivors, biochemical maturation was delayed at days 4 and 5; weight, protein, total creatine kinase activity, and creatine kinase-MB were decreased in antibody-treated embryos. By contrast, insulin (50 ng/embryo) administered to 2-day-old embryos yielded nearly symmetrical stimulatory results. These findings suggest that endogenous insulin plays a probable physiologic role regulating growth and differentiation in early embryos. In addition, the findings provide some clues to a possible function for insulin produced outside the organism's own beta cells.