Radioimmunoassays have recently made it possible to measure the concentration of gastrin in human plasma (Hansky and Cain, 1969; Byrnes, Young, Chisholm, and Lazarus, 1970; McGuigan and Trudeau, 1970; Yalow and Berson, 1970). It has been shown that the plasma gastrin rises in response to such stimuli as the ingestion of food and insulin hypoglycaemia. However, little is known about any quantita...

I describe a radioimmunoassay for human prothrombin, with use of a double-antibody technique. Antiserum raised in rabbits was absorbed with Al(OH)3 and heated to 56 degrees C for 30 min. 125I-labeled prothrombin retaining more than 90% of its biological activity was prepared by the iodine monochloride method. The mean concentration of prothrombin in plasma of 12 normal individuals was 100 +/- 2...

Substance P prohormones were identified in the caudate nucleus, hypothalamus, and substantia nigra of human brain. A polypeptide fraction of acidic brain extracts was fractionated on Sephadex G-50. The lyophilized fractions were sequentially treated with trypsin and a substance P-degrading enzyme with strong preference toward the Phe7-Phe8 and Phe8-Gly9 bonds. The released substance P(1-7) frag...

A sensitive and specific radioimmunoassay for cholecystokinin-pancreozymin (CCK-PZ) has been developed, using rabbit antisera to crude porcine hormone. Highly purified porcine CCK-PZ, labelled with (131)I, and repurified by column chromatography on Sephadex G15, was used as tracer. Separation of free from antibody-bound labelled CCK-PZ was carried out using charcoal, ion-exchange resin, or a do...

Sensitive and specific radioimmunoassays have been developed for cyclic adenosine 3’, 5’-monophosphate (CAMP), cyclic guanosine 3’ ,5’-monophosphate (cGMP), cyclic inosine 3’ ,5’-monophosphate (cIMP), and cyclic uridine 3’, 5’monophosphate (cUMP). These assays are based upon competition of the cyclic nucleotide with isotopically labeled cyclic nucleotide derivatives for binding sites on specifi...

A radioimmunoassay for the determination of plasma cortisol is described. The antiserum against cortisol was produced by the immunization of rabbits with cortisol21-BSA synthesized from cortisol via hemisuccinate derivative. The antiserum obtained had high affinity and high specificity for cortisol. 0.002 ml of plasma diluted with water was used for the assay. After 1,000 dpm of tritiated corti...

A column flow-through radioimmune assay for serum myoglobin has been developed. The assay uses antibodies to human or rhesus monkey myoglobin coupled to Sepharose by cyanogen bromide activation and myoglobin labeled by the Chloramine-T method. The labeled myoglobin is stable over two to three half-lives. Serum myoglobin levels were elevated when serum was taken up to 12 hours after myocardial i...

OBJECTIVE To develop radioimmunoassay for hypocretin-2 (Hcrt-2). And search for its presence in certain rat tissues. METHODS Anti-Hcrt-2 serum has been raised in New Zealand white rabbits immunized with a conjugate of synthetic Hcrt-2 with bovine serum albumin. Radioiodination of Hcrt-2 was performed by chloramine T method, followed by purification of radoiodinated material on Sephadex G-25 c...

Radioimmunoassay of serum estrogen (sum of estrone and estradiol-17f3) in 0.5 ml of human serum is described. After dilution of the serum, the estrogens are adsorbed on a Sephadex G-15 column in the presence of dilute HC1 and then eluted with benzene. After evaporation of the benzene eluate, the estrogens are dissolved in bovine serum albumin (5 g/. liter solution, at pH 8.0). An aliquot of thi...

In quantitative estimates from radioimmunoassay, one of four types of response curves is usually used: a freehand curve, a spline function, an equation based upon mass-action considerations, or a logistic equation. This paper comments briefly on the subjectivity and labor of the first and on the overparametrization of the second. It is chiefly concerned to compare the single binding-site equati...