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Ontogeny of vasoactive intestinal peptide receptors in rat ventral prostate
M G Juarranz1, L G Guijarro, A M Bajo
1Departamento de Bioquímica y Biología Molecular, Universidad de Alcalá, Alcalá de Henares, Spain.
Insights
Vasoactive intestinal peptide (VIP) and isoproterenol stimulate rat prostatic adenylyl cyclase, with activity peaking in young adulthood and declining in old age. VIP receptor binding capacity correlates with cyclase activity, but receptor coupling varies with age.
Area of Science:
- Endocrinology
- Molecular Biology
- Developmental Biology
Background:
- Vasoactive intestinal peptide (VIP) is a key regulator of prostatic function.
- Adenylyl cyclase activity is crucial for cellular signaling pathways in the prostate.
- Understanding the ontogeny of these pathways is essential for comprehending prostate development and aging.
Purpose of the Study:
- To investigate the developmental changes in VIP-stimulated adenylyl cyclase activity in the rat prostate.
- To compare the ontogenic pattern of VIP stimulation with that of a beta-adrenergic agonist (isoproterenol).
- To examine the relationship between VIP receptor binding capacity and adenylyl cyclase activity during postnatal development.
Main Methods:
- Measurement of adenylyl cyclase activity in rat prostate homogenates following stimulation with VIP and isoproterenol at different ages.
- Assessment of VIP binding capacity using radioligand binding assays.
- Determination of the molecular mass of the VIP-receptor complex via gel filtration chromatography.
Main Results:
- VIP-stimulated adenylyl cyclase activity exhibited a peak at 2 months (peripubertal), plateaued from 3-12 months (adult), and decreased at 24 months (old age).
- Isoproterenol stimulation followed a similar age-dependent pattern.
- VIP binding capacity correlated with adenylyl cyclase activity in adults (1-12 months), but showed a discrepancy with uncoupled receptors at 0.5 and 24 months.
- The molecular mass of the VIP-receptor complex remained constant at 51 kDa throughout development.
Conclusions:
- Prostatic adenylyl cyclase activity, modulated by VIP and beta-adrenergic pathways, undergoes significant age-related changes.
- VIP receptor coupling efficiency varies during development, influencing cyclase responsiveness.
- The VIP-receptor complex itself is structurally stable during ontogeny.
Abstract:
1. The stimulatory effect of VIP on rat prostatic adenylyl cyclase changes during postnatal development. It peaks at 2 months (peripubertal period), remains in a plateau between 3 and 12 months (adult period), and decreases at 24 months (old period). 2. The stimulation of rat prostatic adenylyl cyclase by the beta-adrenergic agonist isoproterenol follows a pattern rather similar to that of VIP. 3. The values of VIP binding capacity correlate well with those observed for adenylyl cyclase between 1 and 12 months, whereas there appears to exist a great number of uncoupled VIP receptors at 0.5 and 24 months. 4. The apparent molecular mass (51 kDa) of the rat prostatic VIP-receptor complex remains unaltered during ontogenic development.