Abstract: Eleven peptides containing hydroxy-amino-acid have been synthesized manually by stepwise solid-phase method. Three of them were started on BHA-resin, the others on M errifield-resin. TFM SA/TFA/p -cresol were used as cleaving reagent in all peptide-resin(1～11) cleavage. Furthermore, HF cleaving procedure was also used paralleily to five of those peptide-resins for contrast. No conspicuous difference in yield was tbund between TFM SA and HF. The purity of all products was checked by the profiles of analytical reversed phase HP LC (C-18)and the data of amino acid analysis. All synthetic peptides were tested for the effect on progesterone production by rat corpus luteum in vitro. Among them, three peptides, GlyTyr-NH₂, LysTyr-NH₂ and GlySer Lys-OH, showed significant effect (p<0.01) on inhibiting hCG-induced progesterone production.