Antibodies to the C-terminus of the cholecystokinin precursor: radioimmunoassay and immunohistochemical studies in adult and developing rat gut

Antibodies to the extreme C-terminal pentapeptide of procholecystokinin, YEYPS (in the single letter notation), have been used in radioimmunoassay and immunohistochemistry to characterize the material in rat intestine. There is a single major immunoreactive peptide in intestinal extracts that has the properties of the C-terminal tryptic peptide of the CCK precursor. Similar material has previously been found in rat brain. In immunohistochemistry, a population of cells in rat small intestine is revealed, these also contain C-terminal gastrin/CCK activity, but for the most part do not react with gastrin-specific antibodies. During postnatal development their numbers increase considerably. We conclude that the C-terminal flanking peptide of proCCK is a useful marker for sites of CCK production.     

Genetic variation in nutrient response functions

Summary Genetic differences in the non-linear growth response function of Pinus sylvestris seedlings to five nutrient levels are analyzed to estimate the causes of variation. Analyses of genotypic differences as quadratic response functions, as stability coefficients, and as separable functions indicate that the estimation of genetic effects can vary widely depending on the analytical model assumed. The existence of different reaction norms is demonstrated.