PARALLEL MATURATION OF THE PANCREATIC SECRETORY RESPONSE TO CHOLINERGIC STIMULATION AND THE MUSCARINIC RECEPTOR POPULATION

Abstract
The appearance of pancreatic muscarinic receptors during development has been measured by use of the specific ligand [3H]‐quinuclidinyl benzilate ([3H]‐QNB). QNB binding sites are present in foetal pancreas; their maximal concentration is attained at the age of 30 days and a significant decrease is observed in one year old animals. Affinity of [3H]‐QNB for the muscarinic receptor does not change with age. An evaluation of the pancreatic secretory response to a cholinoceptor agonist as a function of age indicates that the development of this response parallels that of the receptor population. It is suggested that, at all ages from 3 days after birth onwards, the maximal secretory response of the exocrine pancreas to a cholinoceptor agonist mobilizes the same proportion of the total population of QNB binding sites.