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Plasma osmolality and exocrine pancreatic secretion.
M Kitagawa1, T Hayakawa, T Kondo
1Second Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Summary
Elevated plasma osmolality significantly reduces pancreatic juice flow and bicarbonate output, independent of protein secretion. Vasopressin appears to mediate this effect, impacting exocrine pancreatic function.
Area of Science:
- Physiology
- Gastroenterology
Background:
- Plasma osmolality is a critical physiological parameter.
- Exocrine pancreatic secretion plays a vital role in digestion.
Purpose of the Study:
- To investigate the effect of increased plasma osmolality on exocrine pancreatic secretion.
- To explore the potential role of vasopressin in this response.
Main Methods:
- Hypertonic saline was administered intravenously to dogs with gastric and pancreatic fistulae.
- Pancreatic juice flow, bicarbonate output, and protein output were measured.
- Plasma osmolality and vasopressin levels were monitored.
Main Results:
- Hypertonic saline infusion reduced pancreatic juice flow and bicarbonate output.
- Protein output stimulated by secretin and cerulein remained unchanged.
- Plasma osmolality elevation correlated negatively with pancreatic juice flow (r = -0.74, p < 0.01).
- Increased plasma osmolality led to higher plasma vasopressin levels.
- Exogenous vasopressin administration inhibited pancreatic secretion dose-dependently.
Conclusions:
- Elevated plasma osmolality inhibits exocrine pancreatic secretion, specifically juice flow and bicarbonate output.
- Vasopressin is implicated as a key mediator in the osmolality-induced suppression of pancreatic secretion.