Failure of Inhibitors of Protein Synthesis to Affect the LH-Releasing Action of Hypothalamic Extracts in Vitro ∗

Abstract

Summary

Anterior pituitary halves from adult male rats were incubated in vitro for 6 hours following a preincubation of 30 min in tissue culture medium 199. The LH release from the glands was determined by the ovarian ascorbic acid depletion assay. Neither puromycin nor actinomycin in doses of 10-80 μg/ml interfered with the “basal” release of LH from the pituitaries. Purified LH-releasing factor (LHRF) enhanced the release of LH, and this enhancement was not influenced by the presence of either of the antibiotics. The LHRF can thus act when protein synthesis is blocked and must facilitate release of preformed LH from the cell. The present results with LHRF are different from those previously obtained with FSHRF whose action in increasing FSH release was blocked by the antibiotics and therefore appeared to require protein synthesis.