Insulin receptors: the binding capacity and localization in the digestive tract during the rabbits neonatal period.
The aim of this study was to localize and measure the receptor-binding capacity for insulin in the stomach, duodenum, ileum, jejunum, caecum, colon and in isolated hepatocytes in 48 rabbits aged 1-7, 14 and 21 days. Two methods were employed: radioimmunoassay (RIA) and receptor-binding assay (RBA). Isolated rabbit hepatocytes were used to estimate the maximal binding (Bo). Insulin (INS) concentrations measured by RIA-INS test were highest in the colostrum (701 microU/mL as 100%) of the does, and in the blood (82 microU/mL) of newborn rabbits during the first day postpartum. The Bo of colostral insulin for isolated hepatocytes was 556 microU/mL, which corresponded to 79.1% of the total binding as assessed by the RIA-INS test. The Bo for insulin binding in the different parts of the digestive tract tested was the highest on the first day (mean 8.0 fM/g) and the lowest on the 6th day postnatally (mean 4.9 fM/g; P < 0.01). The receptor capacity for insulin varied in relation to the different parts of the digestive tract, and with the age of each individual rabbit.
Nowak
J W
JW
Department of Developmental and Experimental Endocrinology, Polish Academy of Sciences, Poznań, Poland.
Styczyńska
E
E
Slebodziński
A B
AB
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D002432:Cecum / Q000378:metabolism; D003106:Colon / Q000378:metabolism; D004064:Digestive System / Q000737:chemistry / Q000378:metabolism*; D004386:Duodenum / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007082:Ileum / Q000378:metabolism; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007583:Jejunum / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D011817:Rabbits; D011863:Radioimmunoassay; D011972:Receptor, Insulin / Q000032:analysis / Q000378:metabolism*; D014018:Tissue Distribution
D007328:Insulin; D011972:Receptor, Insulin