Effect of Inhibitors of Protein Synthesis on the FSH-Releasing Action of Hypothalamic Extractsin Vitro

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Abstract
Puromycln and actinomycin inhibited completely or nearly completely the release of FSH from adult male anterior pituitaries incubated in vitro for 6 hr. in the presence of hypothalamic extract. Both antibiotics were somewhat more effective if added during the 30 min. preincubation period, but this change was significant only in the case of actinomycin. The effect of actinomycin and puromycin was all or none, and the minimal effective dose of either substance to inhibit FSH release was 10 [mu]g/ml. The effective doses of puromycin and actinomycin interfered with the incorporation of labeled substrate into the protein and RNA fractions, respectively, of the incubated pituitaries. There was no effect of either antibiotic on the resting release of FSH which occurred in the absence of hypothalamic extract. Neither antibiotic produced a significant effect on pituitary FSH concentration determined at the end of the incubation period. The antibiotics did not interfere with the assay of FSH at the doses used in these experiments. It is suggested that protein synthesis may be required for the action of the FSH-releasing factor in inducing release of FSH from the anterior pituitary.