Atrial natriuretic factor in patients with acromegaly

Area of Science:

• Endocrinology
• Nephrology
• Cardiovascular Physiology

Background:

• Acromegaly is characterized by chronically elevated plasma volume.
• Extracellular fluid volume homeostasis is often disrupted in acromegaly.
• The role of atrial natriuretic factor (ANF) in acromegaly-related fluid balance is not well understood.

Purpose of the Study:

• To investigate the plasma levels of ANF in patients with active and inactive acromegaly.
• To determine the relationship between plasma volume, growth hormone levels, and ANF in acromegaly.
• To assess the impact of acute fluid loading and successful treatment on ANF levels.

Main Methods:

• Plasma ANF levels were measured in 37 acromegalic patients (active and inactive) and 7 healthy controls.
• Plasma volume and growth hormone concentrations were assessed.
• Seven active and 4 inactive acromegalic patients underwent isotonic saline infusion.
• Five patients were studied before and after successful treatment.

Main Results:

• Plasma ANF concentrations did not differ significantly between active acromegaly, inactive acromegaly, and controls.
• No correlation was found between plasma volume and ANF levels in acromegalic patients.
• Isotonic saline infusion caused a similar, significant increase in ANF levels across all groups.
• Successful acromegaly treatment normalized plasma volume and growth hormone but did not alter ANF levels.

Conclusions:

• Plasma ANF levels are not significantly altered in acromegaly, irrespective of disease activity or plasma volume status.
• ANF does not appear to play a primary role in the chronic extracellular fluid volume expansion observed in acromegaly.
• The response of ANF to acute fluid loading is preserved in acromegaly.