Abstract
The quantity as well as concentration of dopamine in the hypothalamus of the aged rat is about half that in the hypothalamus of the young rat. The reduction in hypothalamic dopamine in old rats is associated with a reduction in the hypothalamic turnover and secretion of dopamine into hypophysial portal blood. The reduced ability of aged animals to secrete dopamine may be due to: (a) a reduction in the number of dopaminergic neurons in the hypothalamus, (b) an inability of the dopaminergic neurons to respond adequately to stimulation, and/or (c) an increase in the rate of secretion of substances, e.g., β-endorphin and 5-hydroxytryptamine, that inhibit dopamine secretion. In contrast to the secretion of dopamine by the hypothalamus, the secretion of prolactin by the hypophysis is greater in aged animals than in young animals. This increased secretion may be due to the reduced concentration of dopamine in portal blood and/or the loss of ability of prolactin cells in the aged hypophysis to process and respond to dopamine.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 135-139 |
| Number of pages | 5 |
| Journal | Peptides |
| Volume | 1 |
| Issue number | SUPPL. 1 |
| DOIs | |
| State | Published - 1980 |
Keywords
- Dopamine and lysosomal enzymes
- Dopamine and prolactin release
- Dopamine and secretory granules
- Dopamine secretion in aging
- Hypothalamic dopamine in aging
- Inhibition of dopamine secretion
- Prolactin release and lysosomal enzymes
- Prolactin release in aging
- Stimulation of dopamine secretion
ASJC Scopus subject areas
- Biochemistry
- Physiology
- Endocrinology
- Cellular and Molecular Neuroscience