Biosynthesis of 5-aminolevulinic acid and heme from 4,5-dioxovalerate in the rat

5-aminolevulinic acid improves chicken sperm motility

Objective

This study investigated the effects of 5-aminolevulinic acid (5-ALA) on the motility parameters, mitochondrial membrane depolarization, and ATP levels in chicken sperm.

Methods

The pooled semen from Barred Plymouth Rock males was used. In the first experiment, the semen was diluted 4-times with phosphate-buffered saline (PBS (-)) containing various concentrations (0, 0.01, 0.05, and 0.1 mM) of 5-ALA, and then the sperm motility parameters after incubation were evaluated by computer-assisted sperm analysis (CASA). In the second experiment, the semen was diluted 4-times with PBS (-) containing 0.05 mM 5-ALA, and then sperm mitochondrial membrane depolarization and ATP levels after 1.5 h of incubation were analyzed with the MitoPT® JC-1 Assay and ATP Assay kits, respectively. In the third experiment, the semen was removed from the seminal plasma and resuspended with the mediums of PBS (-), PBS (-) supplemented with CaCl2 and MgCl2 (PBS (+)) + 5-ALA, PBS (+) + caffeine, and PBS (+) + caffeine + 5-ALA. Then, the sperm motility parameters after incubation were evaluated by CASA. In the last experiment, the semen was treated with the mediums of PBS (-), PBS (-) + 5-ALA, 5.7% glucose, 5.7% glucose + 5-ALA after removing the seminal plasma, and then the sperm motility parameters were evaluated by CASA.

Results

The addition of 0.05 mM 5-ALA significantly increased the chicken sperm motility, progressive motility, linearity, average path velocity, curvilinear velocity, straight-line velocity, and the wobble. The sperm mitochondrial membrane depolarization was also increased by the 5-ALA treatment. The 5-ALA treatment decreased the sperm ATP levels. Both the caffeine treatment and glucose treatment decreased the sperm motility during incubation period.

Conclusion

5-ALA might increase sperm mitochondrial membrane depolarization to utilize the ATP for enhancing sperm movement.

AGXT2: a promiscuous aminotransferase

Alanine-glyoxylate aminotransferase 2 (AGXT2) is a multifunctional mitochondrial aminotransferase that was first identified in 1978. The physiological importance of AGXT2 was largely overlooked for three decades because AGXT2 is less active in glyoxylate metabolism than AGXT1, the enzyme that is deficient in primary hyperoxaluria type I. Recently, several novel functions of AGXT2 have been 'rediscovered' in the setting of modern genomic and metabolomic studies. It is now apparent that AGXT2 has multiple substrates and products and that altered AGXT2 activity may contribute to the pathogenesis of cardiovascular, renal, neurological, and hematological diseases. This article reviews the biochemical properties and physiological functions of AGXT2, its unique role at the intersection of key mitochondrial pathways, and its potential as a drug target.

Use of the dietary supplement 5-aminiolevulinic acid (5-ALA) and its relationship with glucose levels and hemoglobin A1C among individuals with prediabetes

OBJECTIVE

This study examined the association between 5-aminolevulinic acid (5-ALA) and glucose tolerance.

DESIGN

A double blinded, randomized prospective parallel-group comparison study.

SETTING

Participants were recruited from the community in Honolulu, Hawaii, using radio and TV ads, and at community events.

PARTICIPANTS

One hundred fifty-four males and females ages 40-70 years, with evidence of prediabetes: hemoglobin A1c (HbA1c) 5.8%-7.0% at the screening visit.

INTERVENTION

Participants were randomized equally to one of three study groups: (1) low dose 5-ALA supplement (15 mg capsule); (2) high dose 5-ALA (50 mg capsule); and (3) control (placebo capsule of identical size and color).

MAIN OUTCOME MEASURES

HbA1c and 2 hours post-oral glucose tolerance test (OGTT) glucose levels.

RESULTS

Among individuals taking 5-ALA supplements for 12 weeks, 2 hours post-OGTT glucose levels declined significantly compared to those not taking the supplement (p= 0.02). The relationships were stronger among those with baseline glucose intolerance, or 2 hours post-OGTT glucose measurements greater than 140 mg/dL (p= 0.005 and p= 0.02 for the low and high dose group, respectively). Similar trends were observed for HbA1c but results were of borderline significance (p= 0.07). No untoward effects were reported.

CONCLUSIONS

Further studies are indicated. The potential benefits of 5-ALA dietary supplementation are affirmed by this investigation.