Priming effect of luteinizing hormone releasing factor: in vitro and in vivo evidence consistent with its dependence upon protein and RNA synthesis

Abstract

The aim of this study was to determine whether the priming effect of LH RF depends upon RNA and protein synthesis. In in vivo studies saline, actinomycin D, or cycloheximide was administered i.p. 3.5-4 h before the first i.v. injection of synthetic LH RF into pro oestrus rats anaesthetized with sodium pentobarbitone at 13.30 hr. The LH response to the second injection of LH RF (given 60 min after the first) was markedly reduced by the inhibitors, but the response to the first injection was not significantly affected. Studies with cycloheximide given i.v. showed that the inhibition of protein synthesis up to the second injection of LH RF reduced the magnitude of the priming effect, the reduct..