Reference

Crystal growth of some urinary stone constituents: I

Crystal growth of some urinary stone constituents: I. In-vitro crystallization of L-tyrosine and its characterization. Ramachandran, E.; Natarajan, S. (Department of Physics, Thiruvalluvar College, Papanasam 627425, India). Crystal Research and Technology, 37(11), 1160-1164 (English) 2002 Wiley-VCH Verlag GmbH & Co. KGaA. CODEN: CRTEDF. ISSN: 0232-1300. DOCUMENT TYPE: Journal CA Section: 34 (Amino Acids, Peptides, and Proteins) Section cross-reference(s): 75 L-Tyrosine (C9H11NO3) is an amino acid constituent of urinary stone. Having morphol. of spherulitic needles and long needles, L-tyrosine is crystd. in silica gel under suitable pH conditions and by single diffusion and double diffusion methods. The grown crystals were characterized by d. measurement, Fourier transform IR spectroscopy, x-ray powder diffraction and thermogravimetric anal.

Effect of L-tyrosine on 3b-hydroxysteroid dehydrogenase (3b-HSD) activity of rat luteal cells in vitro

Effect of L-tyrosine on 3b-hydroxysteroid dehydrogenase (3b-HSD) activity of rat luteal cells in vitro. Wang, Huiping; Ni, Jiang; Cheng, Zhiping (School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province 310031, Peop. Rep. China). Zhongguo Yingyong Shenglixue Zazhi, 20(2), 190-193 (Chinese) 2004 Zhongguo Yingyong Shenglixue Zazhi Bianjibu. CODEN: ZYSZE2. ISSN: 1000-6834. DOCUMENT TYPE: Journal CA Section: 13 (Mammalian Biochemistry) Section cross-reference(s): 2 Luteal cells were isolated from ovary tissues of female rats pretreated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG), and were cultured with 95% oxygen and 5% carbon dioxide at 37°. The activity of 3b-hydroxysteroid dehydrogenase (3b-HSD) was measured by RIA. L-Tyrosine (0.2 mmol×L-1 and 2.0 mmol×L-1) could significantly inhibit the activity of 3b-HSD, while the same concns. of L-phenylalanine and L-dopamine had no effects on the activity of 3b-HSD. L-Tyrosine (0.2 mmol×L-1) exerted different effects on 3b-HSD activity at different concns. of pregnenolone. The 3b-HSD activity was increased when the pregnenolone concn. was between 0.1 mmol×L-1 and 1 mmol×L-1. With further increase in the pregnenolone concn. up to 100 mmol×L-1, the stimulating effect of L-tyrosine was switched to suppression effect. Both L-tyrosine and L-tyrosine hydrazide inhibited 3b-HSD activity induced by hCG. L-Tyrosine significantly affects 3b-HSD activity of rat luteal cells in vitro, which is closely correlated with the substrate concn.