Abstract:
A procedure to study the in vitro release of HPL was developed.
Hormone release, partially uncoupled from hormone biosynthesis, was
measured by incubating placental fragments in physiological salt solutions
for short periods. The effect of test substances and different ionic
environments on HPL release were tested to ascertain the roles of calcium
ion and cyclic AMP in the release mechanism.
2. The HPL concentration of the incubation media was measured
with a specific radioimmunoassay. Particular features of the assay were
the use of high concentrations of reagents, and the separation of antibody-bound
and free hormone by ethanol fractionation. The assay had a useful
range of 75-800 ng HPL/m1 with interassay and intra-assay variations of
14.7% and 3.2%, respectively.
