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Polyamines induce precocious development in rats. Possible interaction with growth factors
Insights
Daily polyamine injections in newborn rats accelerated somatic and neurobehavioral development. This treatment also protected against weight loss from surgical injury, suggesting polyamines
Area of Science:
- Biochemistry
- Developmental Biology
- Neuroscience
Background:
- Polyamines (putrescine, spermidine, spermine) are essential biogenic compounds.
- Their role in postnatal development and response to injury requires further elucidation.
Purpose of the Study:
- To investigate the effects of exogenous polyamines on postnatal growth and neurobehavioral development in rats.
- To explore the potential mechanisms of polyamine action, including influence on growth factors and hormonal pathways.
Main Methods:
- Daily subcutaneous injections of putrescine, spermidine, and spermine (10 mg/kg each) to newborn rats.
- Assessment of body weight, developmental milestones (eyelid/ear opening), and neurobehavioral reflexes (righting/gripping).
- Histological analysis of the superior cervical ganglion and immunohistochemical detection of growth factors (NGF, EGF) in specific tissues.
Main Results:
- Polyamine treatment slightly enhanced normal weight gain but significantly prevented weight loss post-surgical injury.
- Accelerated maturation of eyelid/ear opening and righting/gripping reflexes observed.
- Increased superior cervical ganglion neuron count, unaffected by neonatal castration.
- Apparent increase in nerve growth factor (NGF) in iris and salivary gland; no change in epidermal growth factor (EGF).
Conclusions:
- Exogenous polyamines can accelerate somatic and neurobehavioral development in newborn rats.
- Polyamines may influence growth factors, warranting further quantitative investigation.
- Exogenous polyamines may promote growth in cell types dependent on these compounds during specific developmental periods.
Abstract:
The study reports the effects of daily subcutaneous injections of the biogenic polyamines putrescine, spermidine and spermine (10 mg/kg each) given for a short postnatal period, on growth and development of rats. Polyamine treatment, while only slightly enhancing normal body weight gain, prevented the weight loss caused by surgical injury of 5-day-old animals. The treatment resulted in earlier eyelid and ear opening and in earlier maturation of righting and gripping responses. Increased number of neurons in the superior cervical ganglion that is caused by polyamine treatment, could not be prevented by castration of newborn rats, thus excluding the testes as a site through which polyamines may exert their action. An apparent increase in immunohistochemically detectable nerve growth factor was evident in iris and submaxillary salivary gland of polyamine-treated animals, but no change in epidermal growth factor immunohistochemistry was detected in the salivary gland. We conclude: (1) treatment of newborn rats with polyamines can accelerate somatic and neurobehavioral development; (2) further studies are required in order to verify and quantitate the effects of polyamines on growth factors, and (3) the results imply that exogenous polyamines may exert their growth-promoting effects on a number of cell types when these cells experience periods of polyamine dependence.