Rapid receptor-mediated catabolism of 125I-atrial natriuretic factor by vascular endothelial cells.

The binding, internalization and degradation of 200 pM monoiodinated human atrial natriuretic factor-(99-126) (125I-hANF) by cultured bovine aortic endothelial cells (BAECs) were studied at 37 degrees C. 125I-hANF was rapidly cleared from the extracellular medium (t1/2 approximately 10 min), whereas preincubation of the cells in the presence of 20 mM-NH4Cl or 0.2 mM-chloroquine resulted in a significant inhibition of this process.

Subclinical adrenocortical insufficiency in renal amyloidosis.

In order to investigate the functional significance of possible adrenal amyloid infiltration in patients with renal amyloidosis, we performed corticotrophin stimulation tests in 15 patients having renal amyloidosis with no clinical evidence of adrenocortical insufficiency and 12 controls. In 7 of the patients, the cortisol increments obtained during the test were found to be consistent with primary adrenal insufficiency due to possible amyloid infiltration of the adrenal cortex; in contrast, in all control subjects, adrenal responses to the test were regarded as sufficient for proper adrenal function.

Metabolism of 125I-atrial natriuretic factor by vascular smooth muscle cells. Evidence for a peptidase that specifically removes the COOH-terminal tripeptide.

The addition of 200 pM monoiodinated human atrial natriuretic factor-(99-126) (125I-hANF) to cultured bovine aortic smooth muscle cells at 37 degrees C resulted in a rapid clearance from the medium (t1/2 approximately 7.5 min). Within 5 min, [125I]iodotyrosine126 (125I-Y), Arg125-[125I]iodotyrosine126 (125I-RY) and Phe124-Arg-[125]iodotyrosine126 (125I-FRY) appeared in the medium.