Related Experiment Videos
Biogenic amine control of growth hormone secretion in the fetal and neonatal rat
Insights
Biogenic amines control growth hormone (GH) secretion in fetal and neonatal rats. Serotonin and dopamine blockers reduce GH levels, suggesting a similar regulatory mechanism to adults.
Area of Science:
- Neuroendocrinology
- Developmental Biology
- Pharmacology
Background:
- The hypothalamic-pituitary axis regulates growth hormone (GH) secretion.
- Understanding the developmental control of GH secretion is crucial for pediatric health.
- Biogenic amine involvement in GH regulation is established in adult mammals.
Purpose of the Study:
- To investigate the role of biogenic amines in regulating GH secretion during late fetal and early neonatal development in rats.
- To determine if serotonin and catecholamines influence GH levels in the perinatal period.
- To compare GH regulation in neonatal rats with adult and human models.
Main Methods:
- Studied GH secretion in rat fetuses (21-22 days gestation) and neonates (0-72 hours after birth).
- Administered serotonin blocker cyproheptadine (Cypro) and catecholamine dopamine (DA) via injection.
- Measured serum GH levels in treated and saline-controlled animals.
- Utilized dimethoxyphenylethylamine (DMPEA), a dopamine derivative, as a control substance.
Main Results:
- Cyproheptadine and dopamine injections significantly reduced serum GH levels in fetuses and neonates.
- The dopamine derivative DMPEA did not affect serum GH levels compared to controls.
- These findings indicate a role for specific biogenic amines in GH regulation during this developmental window.
Conclusions:
- Biogenic amines, including serotonin and dopamine, exert control over GH secretion in late-term fetuses and early neonates.
- This developmental regulation appears similar to that observed in adult rats and humans.
- The results suggest that GH secretion in early life may be mediated through serotonin receptors.
Abstract:
The development of the hypothalamic-pituitary axis for growth hormone (GH) secretion has been studied in the rat fetus and in the neonate 4, 24, 48 and 72 h after birth. Injections of the serotonin blocker cyproheptadine (Cypro) and a catecholamine, dopamine (DA), each led to reductions in the level of serum GH in 21 to 22 day fetuses and in neonates up to 3 days after birth. The O-methylated derivative of dopamine, dimethoxyphenylethylamine (DMPEA), did not alter serum GH levels from those seen in saline-treated control animals. These results indicate that biogenic amines exert control over GH secretion in the fetus, close to term, and in early neonatal period. They suggest that this control is similar to that seen in the adult rat and in man and that such control may operate through serotonin receptors.