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Immunoreactive vasoactive intestinal polypeptide in rat hypophysial portal blood
Endocrinology
|February 1, 1981
Summary
Vasoactive intestinal polypeptide (VIP) is present in rat hypophysial portal blood, suggesting it originates from the hypothalamus. This peptide may regulate pituitary function through the portal system.
Area of Science:
- Neuroendocrinology
- Hormone Research
Background:
- Vasoactive intestinal polypeptide (VIP) is a peptide hormone with diverse physiological roles.
- The precise origin and function of VIP within the hypothalamic-pituitary axis were not fully elucidated.
Purpose of the Study:
- To investigate the presence and source of VIP in the hypophysial portal blood of rats.
- To determine if VIP secreted from the hypothalamus influences pituitary function.
Main Methods:
- Radioimmunoassay (RIA) was employed to measure VIP concentrations.
- Hypophysial portal blood and peripheral plasma were collected from rats under anesthesia.
- Gel chromatography was used to characterize immunoreactive VIP.
Main Results:
- Significant concentrations of VIP were detected in hypophysial portal blood (mean 1332-1735 pg/ml).
- VIP levels in peripheral plasma were substantially lower (<100 pg/ml).
- Immunoreactive VIP from portal blood matched authentic VIP on gel chromatography.
Conclusions:
- The hypothalamus is a likely source of VIP found in the hypophysial portal circulation.
- VIP may act as a neurohormone modulating pituitary function via the portal system.