Biomedical subjects

T T Daabees

Publications and source records attributed to T T Daabees.

5 recordsLinked to original sources

PubMed1979

Utilization of L-alanyl-L-tyrosine by nephrectomized rats when infused as part of a total parenteral nutrition regimen.

L-Alanyl-L-tyrosine is well utilized as a tyrosine source in parenterally fed rats. Such utilization may depend upon filtration of peptide into the glomerular filtrate, reabsorption into renal epithelial cells, hydrolysis to component amino acids in or at the surface of epithelial cells, and release of component amino acids to the blood. Bilaterially nephrectomized rats were infused with a parenteral solution providing L-alanyl-L-[U-14C]-tyrosine at 0.5 mmoles/kg over a 2 hour period to test this hypothesis. Despite the absence of kidneys, peptide did not accumulate in plasma or tissues. Plasma and liver tyrosine and alanine levels increased significantly over values noted in animals infused without peptide. One-quarter to one-third of the infused radioactivity was released as 14CO2, with the remainder found in the tissues. Between 15 and 51% of radioactivity in individual tissues was free tyrosine, the remainder was incorporated into protein. Isolation of this protein, acid hydrolysis and simultaneous radioactivity-amino acid analysis demonstrated that 94 to 99% of the radioactivity in protein was tyrosine. The data indicate good utilization of alanyl-tyrosine by nephrectomized rats when administered as part of a total parenteral nutrition regimen.

Animals↗

PubMed1979

L-alanyl-L-tyrosine as a tyrosine source during total parenteral nutrition. Infusion at 0.5 and 2 mmoles/kg/day in adult rats.

Tyrosine peptides, such as L-alanyl-L-tyrosine, have excellent solubility and are potential sources of iv tyrosine. Infusion of L-alanyl-L-U-14C-tyrosine as part of a total parenteral nutrition regimen in the rat at a level of 0.5 mmole/kg/day resulted in rapid labeling of tissue tyrosine pools, production of 14CO2, incorporation of 14C-labeled tyrosine into protein, and minimal urinary losses (7.7%). Plasma tyrosine levels, however, remained at fasting. Infusion of L-alanyl-L-tyrosine at 2 mmole/kg/day increased plasma tyrosine above fasting levels and maintained tissue tyrosine at levels seen in orally fed control animals without increasing the percent lost in urine (5.5%). Rapid utilization of L-alanyl-L-tyrosine was noted at both infusion levels with no accumulation of peptide noted in plasma. Plasma and tissue free tyrosine pools were rapidly labeled, as was tissue protein. Radioactivity incorporated in tissue protein was shown to be tyrosine after acid hyrolysis.

Alanine↗

PubMed1978

L-alanyl-L-tyrosine as a tyrosine source during intravenous nutrition of the rat.

Tyrosine is considered an essential amino acid for some premature infants, but its limited solubility prevents addition to intravenous solutions in adequate amounts. Tyrosine peptides with solubilities greater than tyrosine were synthesized to evaluate potential for intravenous use. Intraperitoneal injection of L-alanyl-L-[U-14C]tyrosine (0.5 mmoles/kg) into adult rats resulted in a rapid labeling of tissue pools and production of 14C-CO2. When the peptide was infused as part of an intravenous nutrition solution (0.5 mmoles/kg/24 hours) into adult rats, plasma and tissue tyrosine pools were rapidly labeled. The radioactivity distribution after 24 hours of infusion was: 41% CO2, 13.4% muscle, 7.7% urine, 7.1% liver, 5.5% intestine, 1.4% kidney, with the remainder in other carcass organs. No unhydrolyzed peptide was found in tissue homogenates. Between 9% and 17% of the radioactivity present in tissue was free tyrosine, with the remainder in tissue protein. Tyrosine accounted for more than 96% of this protein bound radioactivity. The data indicate good utilization of alanyl-tyrosine as a tyrosine source when administered intravenously.

Amino Acids↗

PubMed1978

Synthesis of some alkoxybenzamide derivatives as smooth muscle relaxant agents.

The preparation of 16 new N-substituted p-aminobenzamide derivatives which contain diethylaminoethyl-N-methylpiperazine, piperidine and morpholine moieties were described. Preliminary pharmacological testing of representative compounds showed that some of the prepared compounds possess anticholinergic and antihistaminic activities.

Animals↗

PubMed1978

Steroidal derivatives. Part 1: some novel steroidal thiosemicarbazones. Their synthesis, anticancer and endocrinological activities.

The synthesis of several novel thiosemicarbazone derivatives of steroids, including estrogens and androgens, is described. Evaluation of the products in P 388 Lymphocytic Leukemia indicated no anticancer activity. The endocrinological screening showed that estrogenicity is slightly reduced but not abolished in the thiosemicarbazones derived from estrone-3-methyl ether (compounds 1, 2 and 4). The androgenic activity of the thiosemicarbazones derived from testosterone (compounds 7--9) was more pronounced than that of testosterone. Among the same thiosemicarbazone derivatives 7--9, only o-tolyl derivative 8 exhibited anabolic activity.

Animals↗