Plasma levels of secretin in man and dogs: validation of a secretin radioimmunoassay

Journal Article · Tue Jun 01 04:00:00 EDT 1976 · Surgery; (United States)

OSTI ID:7226308

Rayford, P L; Curtis, P J; Fender, H R; Thompson, J C

We have developed and validated a secretin radioimmunoassay that is sufficiently sensitive to measure circulating levels of secretion in the plasma of man and dogs. At a final dilution of 1 : 50,000, the antibody bound 30 percent to 40 percent of radioiodinated (/sup 125/I) 6-tyrosyl synthetic secretin. Pure natural porcine secretin was used as a reference standard and a linear dose-response curve was generated with 10 to 1,000 pg. of the polypeptide. Little or no cross-reactivity was found when graded doses of other gastrointestinal polypeptides were assayed in the radioimmunoassay and immunoreactive secretin (IRS) in volumes of serum up to 300 ..mu..l could be measured accurately. Mean basal levels of IRS in the peripheral plasma of 22 normal human subjects was 216 +- 11.8 pg. per milliliter, in the peripheral plasma of dogs was 154 +- 6.1 pg. per milliliter, and in the portal plasma of dogs was 283 +- 22.2 pg. per milliliter. Basal IRS levels in portal plasma were significantly higher than in peripheral plasma (p < 0.05). In studies on the release of secretin in three normal human subjects, the mean basal level of secretin in peripheral plasma was 124 +- 8 pg. per milliliter. This level was increased to 137 +- 6, 137 +- 7, 149 +- 9, and 169 +- 10 pg. per milliliter during duodenal acidification with 0.15, 0.30, 0.77, and 1.25 mEq. 0.1N HCl per minute. The secretin response was related to the amount of acid used to irrigate the duodenum. In six dogs mean basal levels of secretin in the portal vein were 438 +- 102 pg. per milliliter. Secretin levels were significantly elevated above basal (p < 0.05) at 5, 10, 15, 20, 25, and 30 minutes during irrigation of the duodenum with 0.1N HCl and remained elevated for 5 and 10 minutes after duodenal acidification.

• Research Organization: Univ. of Texas, Galveston
• OSTI ID: 7226308
• Journal Information: Surgery; (United States), Journal Name: Surgery; (United States) Vol. 79:6; ISSN SURGA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD PLASMA
BODY FLUIDS
DAYS LIVING RADIOISOTOPES
DOGS
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
IMMUNE SERUMS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MAN
NUCLEI
ODD-EVEN NUCLEI
PRIMATES
RADIOASSAY
RADIOIMMUNOASSAY
RADIOISOTOPES
SECRETIN
TRACER TECHNIQUES
VERTEBRATES