Improved solid phase synthesis of luteinizing hormone releasing hormone analogues using 9-fluorenylmethyloxycarbonyl amino acid active esters and catalytic transfer hydrogenation with minimal sidechain protection and their biological activities.

Using mainly 9-fluorenylmethyloxycarbonyl amino acid 2, 4, 5-trichlorophenyl esters in the presence of 1-hydroxybenzotriazole and the solid support p-alkoxybenzyl alcohol resin, synthesis of luteinizing hormone releasing hormone analogues was carried out with minimal side-chain protection. Catalytic transfer hydrogenation was employed for removal of NO2 and Z-groups from Arg and < Glu respectively avoiding the use of HF and this led to good yields. An aromatic, hydrophilic amino acid, D-(p-hydroxyphenyl) glycine was incorporated into luteinizing hormone releasing hormone molecule along with other modifications. The agonistic as well as antagonistic activities of all the peptides have been studied.

Effect of luteinizing hormone releasing hormone analogues on testosterone metabolism in vitro —A study with mature rat ventral prostates.

The effects of two luteinizing hormone releasing hormone analogues (a superagonist and an antagonist) on the conversion of testosterone to dihydrotestosterone in homogenates prepared from adult rat ventral prostates were studied. At higher doses, the superagonist showed a significant dose-dependent inhibition of the conversion of testosterone to dihydrotestosterone. In comparison, the antagonist showed only a marginally inhibitory trend. The implications of these observed effects vis-a-vis the use of the analogues in the endocrine management of prostatic cancer have been discussed.