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N Tanphaichitr

Publications and source records attributed to N Tanphaichitr.

45 records · Page 3Linked to original sources
PubMed1977

Levels of L-carnitine and L-O-acetylcarnitine in normal and infertile human semen: a lower level of L-O-acetycarnitine in infertile semen.

The level of total L-carnitine was determined in normal human seminal plasma and sperm. Most of the L-carnitine is concentrated in the seminal plasma and its level is about 10 times higher than that in blood plasma. About 50% of total L-carnitine in normal human seminal plasma exists in the form of acetylcarnitine. Similar studies were also carried out in oligospermic and azoospermic human seminal plasma. The level of L-O-acetylcarnitine in both types of infertile samples is significantly lower than that in normal samples. On the other hand, the level of free L-carnitine is the same in fertile and infertile seminal plasma.

Acetylcarnitine↗
PubMed1977

In vitro stimulation of human sperm motility by acetylcarnitine.

An increase in motility of ejaculated human spermatozoa was observed after the addition of acetylcaritine or carnitine. Similar results were also obtained in the diluted semen with 25--30% initial motilities. However, indirect evidence suggests that carnitine is converted to acetylcarnitine prior to its stimulatory action. In addition, this stimulation was shown to be the result of no increase in ionic strength nor any change in the levels of ATP.

Acetylcarnitine↗
PubMed1976

Production of high levels of phosphorylated F1 histone by zinc chloride.

Methods have been sought to perturb the level of phosphohistones. ZnCl2 (10 mM) exhibits histone phosphate phosphatase in vivo in HTC cells and leads to hyperphysiological levels of F1 phosphohistone. Treatment of tissue culture cells with this concentration of ZnCl2 leads to a reduction in medium pH to 6.4. Control experiments have indicated that HTC cells grow efficiently at this pH and that the reduction of pH does not produce the hyperphosphorylated state per se. The optimum conditions for the ZnCl2 effect are described. That the effect of ZnCl2 on the heterogeneity of F1 histone is due to an effect on phosphorylation was demonstrated by the observation that the entire effect is abolished by treatment with alkaline phosphatase. The site of phosphorylation is in the carboxy-terminal end of the F1 molecule. The inhibitory effect of ZnCl2 on F3 phosphorylation in metaphase cells is also described.

Alkaline Phosphatase↗
PubMed1976

Relationship between chromosome condensation and metaphase lysine-rich histone phosphorylation.

Treatment of metaphase HTC cells with ZnCl2 inhibits histone phosphatase activity and leads to an increase in the hyperphosphorylated forms of the lysine-rich (F1) histone. Under normal conditions a massive phosphatase activity is triggered as the cells shift from M into G1 phase. In the presence of ZnCl2 this activity is abolished and thehyperphosphorylated form of F1 persists intact into G1. We have asked the simple question of whether the chromosome can still extend during the M-G1 transition even if the F1 histone is maintained in the hyperphosphorylated form. We observe an apparently normal extension os the chromosomal material under these conditions, though it is evident that high levels of ZnCl2 have rather substantial effects on other cell functions.

Cell Division↗
PubMedDate not supplied

Differential effects of (+) and (-) gossypol enantiomers on mitochondrial function and proliferation of cultured TM4 cells.

The in vitro effects of (+) and (-)gossypol enantiomers on the mitochondrial functions of mouse transformed Sertoli, TM4 cells were investigated by monitoring mitochondrial rhodamine 123 accumulation. When TM4 cells were cultured in medium without fetal calf serum, 5 micrograms/ml of both enantiomers caused similar declines in mitochondrial rhodamine 123 staining. By contrast, (-)gossypol had a greater adverse action than did (+)gossypol on the mitochondrial of TM4 cells that were cultured in medium supplemented with 2% fetal calf serum. Construction of dose response curves for the effects of the two enantiomers on rhodamine 123 accumulation by TM4 cells after 5 hr of drug treatment gave an EC50 of 7.5 micrograms/ml for the (-)gossypol isomer compared with 18 micrograms/ml for the (+)gossypol isomer. Similarly, TM4 cell proliferation was also more disturbed by (-)gossypol in medium supplemented with other concentrations of fetal calf serum. The results suggest that the lower effect of (+)gossypol on TM4 cells may be attributed to its higher affinity to serum components, which may impede its entrance into TM4 cells.

Animals↗
PubMedDate not supplied

Incorporation of gossypol and formation of its protein conjugates in mouse transformed Sertoli (TM4) cells.

Mitochondria of both mouse transformed Sertoli (TM4) cells and primary-cultured rat and mouse Sertoli cells were shown to be preferentially affected by gossypol (Tanphaichitr et al, 1984). To investigate whether this selective effect was due to a greater of TM4 cells to accumulate gossypol, TM4 and other somatic cell lines, including dog (MDCK) and kangaroo (PtK2) kidney epithelial cells, rat embryo fibroblasts (Rat-1) and mouse BALB/c 3T3 fibroblasts, were incubated with [14C]gossypol and the incorporated specific activity of the drug was assessed. The results indicate that TM4 cells accumulated [14C]gossypol at the highest level. Incorporated [14C]gossypol appeared to bind to TM4 cell macromolecules and remained in the dialysis tubing after extensive dialysis. Characterization of these gossypol-conjugated proteins by SDS-polyacrylamide gel electro-proteins had apparent Mr's of 92,500, 70,000, 63,200, 60,000, 58,100, 54,000, 52,000, 50,000, 47,500, 40,000 37,000, 35,000, 30,000, 20,000, and 14,500 daltons. Conjugation of these proteins with gossypol may result in macromolecular dysfunction and abnormal structure.

Animals↗