| dc.description.abstract | A method was developed for the assay of very small quantities
of radioactively-labelled peptide chains of human hemoglobin based
upon the formation of complex with porcine haptoglobin, and subsequent
precipitation of the complex with antiserum to the haptoglobin.
Attempts to apply the method to a kinetic study of
synthesis of the globin chains of embryonic chick hemoglobins
in explanted chick blastodiscs were unsuccessful. Exploratory
studies indicated one of the reasons for this failure is probably
a relatively low affinity of the embryonic chick Hbs for porcine
haptoglobin. Although the plasma of 8 week old chicks contained
a haptoglobin, no evidence was obtained for the presence of this
protein in the circulation of the 10 day embryo and supporting
membranes.
Reports in the literature indicate that levels of aminolevulinate
synthetase enzyme present in individual chick blastodiscs
are sufficient for assay by highly sensitive radiochemical
methods. However activity was not detectable by the most
sensitive method of assay currently available and prior positive
observations reflect artefacts of the assay method used.
The course of development of serotonin N-acetyltransferase
activity in the chick pineal during development to 18 days post hatch had no appreciable effect upon the course of increase in activity. However, a diurnal cycle in levels of activity was observed with
birds examined at 16 days post hatch. Preliminary studies of
organ cultures of embryonic chick pineal gland indicate that the
developmental increase in serotonin N-acetyltransferase activity
is probably not induced solely in response to norepinephrine. | en_US |
