The international standard for atrial natriuretic factor. Calibration by an international collaborative study.

Biochemistry of natriuretic peptides

“…In this study the same samples gave substantially different results although the rank order of plasma results within assays were similar. Direct assays tended to give higher and more variable results [97]. Because of the structural similarities between ANP and BNP, extraction and assay methods for BNP are similar to those for ANP.…”

Atrial Natriuretic Peptide

“…Therefore, results obtained using the direct method should be interpreted with caution (Poole et al 1988;Richards et al 1987;Tan et al 1989). Although the direct method is less laborious and costly than the indirect method, the measurement of immunoreactive ANP without prior purification of plasma yields unreliable val-ues due to interference from some (unknown) plasma components.…”

Atrial Natriuretic Peptide

“…No cross- reactivity was observed with different parts of (l-126)hANP not containing the (99-126)hANP fragment. In contrast to the Peninsula antibody, both the S-31 and the S-32 antibodies have no affinity to rat (99-126)ANP, which differs from human (99-126)ANP by only one amino acid on position 110 (see figure [1][2][3]. Knowing that methionine on position 110 of human (99-126)ANP is easily oxi dized to the methionine sulfoxide form and that the antibodies used are highly specific for this methionine, a non-oxidized tracer for these antibodies had to be developed.…”

“…As early as 1935 Peters speculated on the existence of a volume controlling system which could 'sense the fullness of the blood stream' (1). In 1956 Henry, Gauer and Reeves (2) suggested that the heart could detect changes in the central blood volume.…”