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Biomedical subjects

L J Ge

Publications and source records attributed to L J Ge.

21 records · Page 2Linked to original sources
PubMedDate not supplied

Chemical characterization of angiotensin I in porcine follicular fluid.

In the search for novel neuropeptides in porcine follicular fluid (pff) using smooth muscle contractile activity as a response parameter, a substance with a marked activity was isolated in a pure form. By amino acid analysis and sequential study, this substance has been chemically revealed to be angiotensin I. A much smaller amount of additional activity was isolated and found to be angiotensin II, as determined by radioimmunoassay. Radioimmunoassays for angiotensin I and II confirmed that the amount of angiotensin I determined was much greater than that of angiotensin II. A comparative study of the extractions, however, indicated a large amount of angiotensin I had been generated from angiotensinogen by endogenous renin in the follicular fluid which could be activated during extraction and ultrafiltration at a low pH. These findings are consistent with the previous reports that described a high concentration of prorenin in the follicular fluid, acid activation of prorenin to renin and the subsequent generation of angiotensin I from endogenous angiotensinogen.

Amino Acid Sequence↗
PubMedDate not supplied

Structure-activity relationships of analogs of the endogenous brain peptides Tyr-MIF-1 and Tyr-W-MIF-1.

Analogs of the naturally occurring peptides Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) and Tyr-W-MIF-1 (Tyr-Pro-Trp-GLy-NH2) were synthesized and investigated for their opiate agonist as well as antagonist activity in the guinea pig ileum assay. [Tyr5]-Tyr-MIF-1 and the endogenous Tyr-W-MIF-1 were the most potent opiate agonists among the 20 compounds tested. Several analogs showed antiopiate activity in the ileum from morphine-tolerant animals as measured by attenuation of the agonistic effect of DAMGO, which inhibits electrically stimulated contractions of the ileum. The binding activity of the analogs at mu opiate receptors was determined by displacement of [3H]-DAMGO in rat brain. Tyr-W-MIF-1 and its analogs were more potent than Tyr-MIF-1 and its analogs in this binding assay. Thus, Tyr-MIF-1, Tyr-W-MIF-1 and several of their analogs could act as opiate agonists as well as antagonists.

Amino Acid Sequence↗