Serum concentrations of 3, 3'-diiodothyronine, 3', 5'-diiodothyronine, and 3, 5-diiodothyronine in altered thyroid states

To investigate the thyroid hormone metabolism in altered states of thyroid function, serum concentrations of 3, 3'-diiodothyronine (3, 3'-T2), 3', 5'-T2 and 3, 5-T2 as well as T4, T3 and rT3 were determined by specific radioimmunoassays in 17 hyperthyroid and 10 hypothyroid patients, before and during the treatment. Serum T4, T3, rT3, 3, 3'-T2 and 3', 5'-T2 concentrations were all higher in the hyperthyroid patients than in age-matched controls and decreased to the normal ranges within 3 to 4 months following treatment with antithyroid drugs. In the hypothyroid patients, these iodothyronine concentrations were lower than in age-matched controls and returned to the normal ranges after 2 to 3 months treatment with T4. In contrast, serum 3, 5-T2 concentrations in hyperthyroid patients (mean +/- SE : 4.0 +/- 0.5 ng/dl) were not significantly different from those in controls (3.9 +/ 0.4 ng/dl), although they tended to decrease in 3 of 6 patients after the antithyroid drug therapy. Serum 3, 5-T2 levels in the hypothyroid patients (3.8 +/- 0.6 ng/dl) were also within the normal range and showed no significant change following the T4 replacement therapy. However, serum 3, 5-T2 as well as 3, 3'T2 concentrations rose significantly with a marked rise in serum T3 following T3 administration, 75 micrograms/day for 7 days, in Graves' patients in euthyroid state.(ABSTRACT TRUNCATED AT 250 WORDS)     

Synthesis of 2'-O-deuteriomethyl ribonucleosides Gm-d3, Am-d3, Um-d3 and Cm-d3.

The synthesis of 2'-O-deuteriomethyl ribonucleosides by iodomethane-d3 (99.5 + atom % D) deuteriomethylation of 3',5'-O-tetra(isopropyldisiloxane)-diyl nucleosides, followed by deprotection, is described.     

Monodeiodination of thyroxine to 3, 5, 3'-triiodothyronine and to 3, 3', 5'-triiodothyronine in isolated dog renal cortical tubuli

Monodeiodination of T4 to T3 and rT3 in the intact cells of dog renal tubuli and glomeruli was investigated. The tubuli and glomeruli were obtained by a sieve method. T4 (2 micrograms/ml) was incubated in Tris-HCl buffer, pH 7.5, with renal cells (180 micrograms protein/ml) and 5 mM DTT for 1 h at 37 degrees C and the T3 and rT3 generated during incubation were measured by specific radioimmunoassays. In order of decreasing activity, dog renal cortical tubuli, cortical homogenate, glomeruli and medullary tubuli were capable of converting T4 to T3. Net rT3 production from T4 in cortical tubuli was also greater than that in cortical homogenate. The conversion of T4 to T3 and also to rT3 in cortical tubuli was enzymatic in nature, since the reactions showed dependence on time and protein concentration; instability to heating; temperature and pH optimum. The production of T3 and rT3 from T4 was maximum at pH 6.5 and at pH 9.5, respectively, indicating that two different enzymic systems, a 5- and a 5'-monodeiodinase, might be involved in the deiodination of the tyrosyl and the phenolic ring of T4 in dog kidney.     

Syntheses, crystal structures, and hydrogen bonding patterns of 3'-C-methylenecarboxylic-3'-deoxythymidine and 3'-C-methyleneamidilylic-3'-deoxythymidine

Thymidine derivatives containing carboxylic acid and amide groups have been synthesized and the hydrogen-bonding patterns of 3'-C-methylenecarboxylic-3'-deoxythymidine 6 and 3'-C-methyleneamidilylic-3'-deoxythymidine 9 have been characterized by using X-ray crystallography.     

Syntheses of 3-fluoro-, 3-epi-3-fluoro-, and 3,3-difluoro-3-de(methoxy)sporaricin A

3-Fluoro- (4), 3-epi-3-fluoro- (3), and 3,3-difluoro-3-de(methoxy)sporaricin A (5) have been prepared by reaction of diethylaminosulfur trifluoride with the corresponding precursors: 1,2′,6′-tris(N-benzyloxycarbonyl)-4-N, 5-O-carbonyl-3-de(O-methyl)sporaricin B (6), its 3-epi-3-hydroxy isomer (10), and the 3-oxo derivative (9). The structures of 3,4, and 5 were determined by ¹H-, ¹³C-, and ¹⁹F-n.m.r. spectroscopy.     

Cell density and amino acid transport in 3T3, SV3T3, and SV3T3 revertant cells

The transport of selected neutral and cationic amino acids has been studied in Balb/c 3T3, SV3T3, and SV3T3 revertant cell lines. After properly timed preincubations to control the size of internal amino acid pools, the activity of systems A, ASC, L, and Ly⁺ has been discriminated by measurements of amino acid uptake (initial entry rate) in the presence and absence of sodium and of transportspecific model substrates. L-Proline, 2-aminoisobutyric acid, and glycine were primarily taken up by system A; L-alanine and L-serine by system ASC; L-phenylalanine by system L; and L-lysine by system Ly⁺ in SV3T3 cells. L-Proline and L-serine were also preferential substrates of systems A and ASC, respectively, in 3T3 and SV3T3 revertant cells. Transport activity of the Na⁺-dependent systems A and ASC decreased markedly with the increase of cell density, whereas the activity of the Na⁺-independent systems L and Ly⁺remained substantially unchanged. The density-dependent change in activity of system A occurred through a mechanism affecting transport maximum (V_max) rather than substrate concentration for half-maximal velocity (K_m). Transport activity of systems A and ASC was severalfold higher in transformed SV3T3 cells than in 3T3 parental cells at all the culture densities that could be compared. In SV3T3 revertant cells, transport activity by these systems remained substantially similar to that observed in transformed SV3T3 cells. The results presented here add cell density as a regulatory factor of the activity of systems A and ASC, and show that this control mechanism of amino acid transport is maintained in SV40 virus-transformed 3T3 cells that have lost density-dependent inhibition of growth, as well as in SV3T3 revertant cells that have resumed it.     

Interaction of the 5'-phosphates of the anti-HIV agents, 3'-azido-3'-deoxythymidine and 3'-azido-2',3'-dideoxyuridine, with thymidylate synthase

A study has been made of the interaction of 3'-azido-3'-deoxythymidine 5'-phosphate (AZTMP) and 3'-azido-2',3'-dideoxy-uridine 5'-phosphate (AZdUMP) with thymidylate synthase. With the enzyme from L1210 cells and the tapeworm Hymenolepis diminuta, AZTMP was a weak inhibitor competitive with respect to dUMP (Ki = 6.3 mM and 0.5 mM); hence cytotoxicity of AZT, in cells in which accumulation of AZTMP is not high, is not due to inhibition of cellular thymidylate synthase. AZdUMP, with the L1210 enzyme, was a weak substrate (competition with dUMP described by apparent Ki = 4.7 mM), excluding conversion of AZdUMP to AZTMP as a source of toxicity of 3'-azido-2',3'-dideoxyuridine. An efficient procedure is described for enzymatic phosphorylation on a preparative scale of dideoxynucleosides.     

The antiviral activity of 9-beta-D-arabinofuranosyladenine is enhanced by the 2',3'-dideoxyriboside, the 2',3'-didehydro-2',3'-dideoxyriboside and the 3'-azido-2',3'-dideoxyriboside of 2,6-diaminopurine

The 2',3'-dideoxyriboside (ddDAPR), 2',3'-didehydro-2',3'-dideoxyriboside (ddeDAPR) and 3'-azido-2',3'-dideoxyriboside (AzddDAPR) of 2,6-diaminopurine have been previously recognized as potent inhibitors of human immunodeficiency virus replication. These compounds are also potent inhibitors of adenosine deaminase and inhibit the deamination of 9-beta-D-arabinofuranosyladenine (araA). ddDAPR, ddeDAPR and AzddDAPR markedly potentiate the antiviral activity of araA against herpes simplex virus type 1 (HSV-1), type 2 (HSV-2) and vaccinia virus (VV). When used at a concentration of 20 micrograms/ml, which had by itself no antiviral effect, ddDAPR, ddeDAPR and AzddDAPR increased the ability of araA to suppress HSV-1, HSV-2 and VV yield by several orders of magnitude. The maximum antiviral effect was obtained with the combinations of ddDAPR or ddeDAPR with araA concentrations of 1 and 10 micrograms/ml.     

Improved synthesis of 3-keto, 4-ene-3-keto, and 4,6-diene-3-keto bile acids

Cholic and deoxycholic acids can be converted into 3-keto derivatives in 75-80% yield, by a four-step synthesis consisting of formylation, selective deformylation of the 3-formoxyl group, oxidation, then deformylation of the remaining formoxyl groups. The intermediate 3-keto formoxyl acids in this sequence were shown to be suitable starting compounds for the synthesis of 4-ene-3-keto acids, in 55-60% yield, via bromination, dehydrobromination, and deformylation. By extending the dehydrobromination reaction, the 7 alpha-formoxyl group of the intermediate 4-ene-3-keto-7 alpha,12 alpha-diformoxyl acid is also lost, hence providing a useful synthetic route to 4,6-diene-3-keto bile acids.