Biomedical subjects

Masaaki Yoshikawa

Publications and source records attributed to Masaaki Yoshikawa.

3 recordsLinked to original sources

PubMed2002

Albutensin A and complement C3a decrease food intake in mice.

Albutensin A (Ala-Phe-Lys-Ala-Trp-Ala-Val-Ala-Arg) derived from serum albumin dose-dependently decreased food intake after intracerebroventricular (10-50 nmol/mouse) or peripheral (0.3-1.0 micromol/mouse) administration in fasted conscious ddY mice. Albutensin A delayed gastric emptying and elevated blood glucose levels. Although albutensin A showed low affinity for bombesin receptor, it decreased food intake in bombesin receptor knockout mice, indicating that its inhibitory effect on feeding was not mediated through bombesin receptor. Then, we investigated whether the albutensin A-induced decrease in food intake was mediated by complement C3a and C5a receptors, because albutensin A had affinities for these receptors. Des-Arg-albutensin A, lacking affinity for C3a and C5a receptors, did not inhibit food intake. We found for the first time that centrally administered C3a (10-100 pmol/mouse) by itself decreased food intake in fasted mice. In contrast, C5a increased food intake after central injection. Based on these results, we conclude that the inhibitory effect of albutensin A on food intake is mediated through the C3a receptor.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2002

Release of hemorphin-5 from human hemoglobin by pancreatic elastase.

Opioid peptide hemorphin-5 (YPWTQ) was released from human hemoglobin by the action of pancreatic elastase. V-hemorphin-5 (VYPWTQ) was also released under the same conditions. The amount of hemorphin-5 was about 1/10 that of V-hemorphin-5. This is the first report showing release of hemorphin-5 only by the action of one enzyme.

Amino Acid Sequence↗

PubMed2002

Design of a highly potent anti-hypertensive peptide based on ovokinin(2-7).

Ovokinin(2-7) (RADHPF), an orally active antihypertensive peptide derived from ovalbumin, lowers blood pressure in SHRs at a dose of 10 mg/kg. Attempts were made to potentiate its anti-hypertensive activity by replacing the amino acid residues in [Pro2, Phe3]-ovokinin(2-7), which was previously reported to have 33-fold stronger activity than ovokinin(2-7). The anti-hypertensive activity of [Pro2, Phe3]-ovokinin(2-7) was improved by replacement of the C-terminal Phe residue with Trp. Then, the best amino acid residues at other positions for the anti-hypertensive effect were selected. RPLKPW, the most potent derivative obtained, showed significant anti-hypertensive activities at a dose of 0.1 mg/kg after oral administration in spontaneously hypertensive rats (SHRs). Thus, RPLKPW showed 100-fold more potent anti-hypertensive activity than ovokinin(2-7).

Administration, Oral↗