Search PubMed⌕ Search

Biomedical subjects

D L Hwang

Publications and source records attributed to D L Hwang.

42 records · Page 3Linked to original sources
PubMed1984

Effect of corticosterone on carbamylcholine-, leucine-, or calcium-induced insulin secretion by the isolated perfused rat pancreas.

Using the isolated pancreas of male Sprague-Dawley rats, three different concentrations of glucose were tested in the perfusion medium: 4.0, 6.7, and 9.4 mM. The insulinotropic effects of several potent secretagogues were examined with and without a 10(-7)-M corticosterone-21-acetate (CS) background. When the perfusion medium contained 4.0 mM glucose, there was no insulin secretion in the basal state, but 10(-6)M carbamylcholine chloride, 5 mM L-leucine, and 5 mM calcium chloride elicited moderate but sharp responses of insulin output. When the secretagogues were superimposed on CS infusion, their stimulatory effects were abolished. When the perfusion medium contained 6.7 mM glucose, a steady insulin secretion was observed. A 4- to 5-fold stimulation of insulin release was elicited by carbamylcholine, leucine, and calcium. With CS in the perfusate, the secretagogues were ineffective. However, at a higher glucose level (9.4 mM), the stimulants could partially escape the inhibitory effects of CS. It is concluded that CS may play a role in the regulation of insulin output by directly modulating the activities of some potent secretagogues.

Animals↗
PubMed1978

Rapid release of protease inhibitors from soybeans: immunochemical quantitation and parallels with lectins.

Specific antisera were prepared against the Bowman-Birk trypsin inhibitor and four other trypsin inhibitors of low molecular weight isolated from soybeans (Glycine max L. cv. Tracy). These antisera were used to detect the presence and amount of the inhibitors in: (a) seeds and protein extracts of soybean meal; (b) seedlings; and (c) the water surrounding the seeds and roots of seedlings. Lectin activities in seeds, seedlings, and water were also determined at the same time as the protease inhibitor activities. By competitive inhibition of immunoprecipitation, the combined five low molecular weight protease inhibitors were found to constitute the following percentages of proteins (w/w): 6.3% in defatted soybean meal; 8.1% of the protein extracted from the meal by a buffer of pH 8.6; 8.3, 14.7, 15.2, 16.1, 17.2, and 18.9% of the protein in a lyophilisate of water in which seeds were incubated for 4, 8, 12, 16, 20, and 24 hours, respectively; 8.2% in a lyophilisate of water in which roots of seedlings grew for 20 days; 1.5% in cotyledons; and less than 0.1% in epicotyls, hypocotyls, and roots of 12-day-old seedlings. Hemagglutination activities, expressed as the lowest amount of protein required to give a positive agglutination of 0.2 ml of 2% rabbit red blood cells, were as follows: purified soybean lectin, 0.08 mug; lyophilisate of water in which seeds were incubated for 4, 8, 12, 16, 20, and 24 hours, 10, 2.5, 5, 5, and 2.5 mug, respectively; lyophilisate of water in which roots grew for 20 days, 5 mug; 12-day-old cotyledons, roots, epicotyls, and hypocotyls, 12.5, 100, >1,000, and >500 mug, respectively. The results indicate that a large amount of protease inhibitors as well as lectins are released from seeds during the first 8 hours of imbibition. Neither lima bean trypsin inhibitor (mol wt, 10,000) nor Kunitz soybean trypsin inhibitor (mol wt, 21,500) showed competitive inhibition in tests with antisera against low molecular weight soybean protease inhibitors.

Journal Article↗
PubMed1977

Purification, partial characterization, and immunological relationships of multiple low molecular weight protease inhibitors of soybean.

Five protease inhibitors, I--V, in the molecular weight range 7000--8000 were purified from Tracy soybeans by ammonium sulfate precipitation, gel filtration on Sephadex G-100 and G-75, and column chromatography on DEAE-cellulose. In common with previously described trypsin inhibitors from legumes, I--V have a high content of half-cystine and lack tryptophan. By contrast with other legume inhibitors, inhibitor II contains 3 methionine residues. Isoelectric points range from 6.2 to 4.2 in order from inhibitor I to V. Molar ratios (inhibitor/enzyme) for 50% trypsin inhibition are I = 4.76, II = 1.32, III = 3.22, IV = 2.17, V = 0.97. Only V inhibit chymotrypsin significantly (molar ratio = 1.33 for 50% inhibition). The sequence of the first 16 N-terminal amino acid residued of inhibitor V is identical to that of the Bowman-Birk inhibitor; all other observations also indicate that inhibitor V and Bowman-Birk are identical. The first 20 N-terminal amino acid residues of inhibitor II show high homology to those of Bowman-Birk inhibitor, differing by 1 deletion and 5 substitutions. Immunological tests show that inhibitors I through IV are fully cross-reactive with each other but are distinct from inhibitor V.

Amino Acid Sequence↗
PubMed1977

A soybean trypsin inhibitor. Crystallization and x-ray crystallographic study.

Five trypsin and alpha-chymotrypsin inhibitors which have low molecular weights (ranging from 6800 to 8600) and are present in soybean seeds of the Tracy variety have been isolated and purified, and single crystals which give x-ray diffraction data beyond 3-A spacings have been obtained from one of them. The trypsin inhibitor crystallizes in a monoclinic unit cell of symmetry P2(1) and dimensions a = 25.919(7) A, b = 43.23(1) A, c = 19.905(5) A, and beta = 103.63(2) degrees. The assymmetric unit contains 1 molecule of molecular weight 6800. The crystal, which has been found to be unusually stable to x-radiation, has solvent content of approximately 26% by volume.

Crystallization↗
PubMedDate not supplied

Double-blind study of glycerol vs glucose in parenteral nutrition of postsurgical insulin-treated diabetic patients.

Twenty-five insulin-treated diabetic patients were randomly assigned postoperatively to 5 days of intravenous infusions of ProcalAmine (3% amino acids, 3% glycerol, and electrolytes) or FreAmineIII + dextrose and electrolytes. The solutions were given isocalorically and isonitrogenously. Insulin was adjusted to keep glycemia at the level of 150-200 mg/dl. The ProcalAmine group by the 5th day had plasma glucose of 158 +/- 25 mg/dl and required 1.20 +/- 0.10 U/hr insulin. The FreAmine + dextrose group had plasma glucose of 169 +/- 53 mg/dl and required 2.28 +/- 0.13 U/hr. At all time points postsurgically, the ProcalAmine group required less insulin.

Adult↗