Evidence against extrapancreatic insulin synthesis.
Labeled and unlabeled insulin in acid/ethanol tissue extracts can be concentrated up to 100-fold by using a hydrophobic adsorption technique. After adsorption to and elution from an octadecylsilyl silica column, insulin is recovered in yields greater than 75%. By using this method of concentration, insulin in brain tissues of three of four fed rats and one rabbit was found to be less than 20% of plasma concentration. The kidney is the only extrapancreatic organ in which insulin is observed to be markedly above plasma levels. Porcine-insulin-like material was not detectable in guinea pig tissues (less than 0.02 ng/g). It is concluded that insulin is not synthesized in brain or other extrapancreatic tissues and that other mammalian insulins are not found in guinea pig tissues.
D000818:Animals; D001921:Brain / Q000378:metabolism; D006168:Guinea Pigs; D007328:Insulin / Q000096:biosynthesis* / Q000097:blood / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D012822:Silicon Dioxide
D007328:Insulin; C026679:octadecylsilica; D012822:Silicon Dioxide