Urine 3-hydroxykynurenine is higher during the postovulatory phase than in the preovulatory phase indicating a higher vitamin B₆ requirement

Figures & data

Table 1. Comparison of urinary excretion of l-Trp and Its catabolites between preovulatory and postovulatory phases.

	Preovulatory phase	Postovulatory phase	p value
AnA, μmol/d	1.2 ± 0.3	1.1 ± 0.2	0.1702
KA, μmol/d	7.7 ± 2.6	7.6 ± 2.5	0.9496
3-HK, μmol/d	2.1 ± 1.0	5.6 ± 1.6	<0.0001
XA, μmol/d	2.0 ± 0.6	2.2 ± 0.6	0.3644
3-HA, μmol/d	1.9 ± 0.5	2.4 ± 1.1	0.1420
Nam, μmol/d	ND^1	ND^1	–
MNA, μmol/d	33.8 ± 8.7	30.0 ± 8.4	0.1552
2-Py, μmol/d	39.6 ± 12.7	35.3 ± 11.5	0.1378
4-Py, μmol/d	4.7 ± 1.7	4.5 ± 1.9	0.5742

¹ ND = not detected (<0.1 μmol/d).

Sexually mature women aged from 21 to 26 years old were recruited.

Values were means ± SD for 13 women.

Preovulatory phase; 24-h urine samples were collected at the 9th day of the menstrual cycle.

Postovulatory phase; 24-h urine samples were collected at the 21st day of the menstrual cycle.

Fig. 1. Metabolic Pathway of l-Trp.

Notes: 2-AAA, 2-aminoadipic acid; ACMS, α-amino-β-carboxymuconate-ε-semialdehyde; AMS, α-aminomuconate-ε-semialdehyde; AnA, anthranilic acid; N-FK, N-formylkynurenine; 3-HA, 3-hydroxyanthranilic acid; 3-HK, 3-hydroxykynurenine; KA, kynurenic acid; Kyn, kynurenine; MNA, N¹-methylnicotinamide; 2-Py, N¹-methyl-2-pyridone-5-carboxamide; 4-Py, N¹-methyl-4-pyridone-3-carboxamide; Nam, nicotinamide; NaAD, nicotinic acid adenine dinucleotide; NaMN, nicotinic acid mononucleotide; NMN, nicotinamide mononucleotide; 2-OAA, 2-oxoadipic acid; QA, quinolinic acid; Trp, l-tryptophan. (1), kynurenine 3-monooxygenase; (2), kynureninase; (3), kynurenine aminotransferase; (4) 3-hydroxyanthranilic acid 3,4-dioxygenase; (5), α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase; (6) quinolinic acid phosphoribosyltransferase.