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Quantitative modifications induced by angiotensin II on rat bile secretion
L G Bianciotti1, M S Vatta, A E Dominguez
1Cátedra de Fisiopatología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
Regulatory Peptides
|December 15, 1994
Summary
Angiotensin II (ANG II) significantly alters rat bile secretion, decreasing bile flow and electrolyte excretion while increasing bicarbonate and calcium. These findings suggest ANG II
Area of Science:
- Physiology
- Gastroenterology
- Endocrinology
Background:
- Angiotensin II (ANG II) is a key hormone in regulating blood pressure and fluid balance.
- Previous studies have investigated the effects of hormones like atrial natriuretic factor on bile secretion.
- The specific impact of ANG II on bile composition and flow requires further elucidation.
Purpose of the Study:
- To investigate the effects of Angiotensin II (ANG II) on bile secretion in rats.
- To analyze changes in bile flow, electrolyte excretion, and other biliary constituents following ANG II administration.
- To compare the effects of ANG II on bile secretion with those of atrial natriuretic peptide.
Main Methods:
- Rats were intravenously injected with Angiotensin II (ANG II) at a dose of 0.1 microgram/kg every 30 minutes for 120 minutes.
- Bile samples were collected in 30-minute intervals.
- Simultaneous recordings of mean arterial pressure and portal venous pressure were performed before and after ANG II administration.
Main Results:
- ANG II significantly decreased bile flow and the excretion of sodium, potassium, chloride, and bile acids.
- ANG II administration led to an increase in bile pH, osmolality, and the excretion rates of bicarbonate and calcium.
- A rapid, transient increase in mean arterial pressure and portal venous pressure was observed post-ANG II injection.
Conclusions:
- Angiotensin II (ANG II) modulates bile flow and the excretion of various biliary constituents in rats.
- The observed effects of ANG II on bile secretion are not entirely opposite to those of atrial natriuretic peptide, despite its known antagonistic actions.
- These findings suggest a potential role for ANG II in the pathophysiology of conditions like hypertension, characterized by elevated circulating ANG II levels.