Lack of Inhibitory Effect of α-Human Atrial Natriuretic Polypeptide on Cortisol Secretion in Cultured Adrenocortical Adenoma Cells from the Patients with Cushing's Syndrome

Summary

The effects of synthetic α-human atrial natriuretic polypeptide (α-hANP) on cortisol secretion by adrenocortical adenoma cells from patients with Cushing's syndrome (CS cells) in primary monolayer cultures, compared to cultured normal adrenal cells, were studied. α-hANP significantly inhibited cortisol secretion by human normal adrenal cells in culture, but had no direct effect on cortisol secretion from CS cells, in the presence or absence of 10^-8 M ACTH. α-hANP enhanced the accumulation of intracellular cyclic GMP in normal adrenal cells in culture, but not in CS cells. Visualization of [¹²⁵I] iodo-α-hANP-specific binding sites by an in vitro receptor autoradio-graphic technique showed that these sites were lacking in adrenocortical adenoma tissues. These results suggest that the loss of α-hANP inhibitory effect on cortisol secretion in CS cells may be due to the absence of α-hANP receptor sites.

Key-Words

Atrial Natriuretic Polypeptide - Cushing's Syndrome