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Increased free phenylalanine in the milk of a phenylketonuric mother
340
SHORT
COMMUNICATIONS
significant prolongation of life using the low-phenylalanine and lowtyrosine diet compared to the calorie-restricted group. Therefore, it appears that a low-phenylalanine and low-tyrosine diet has a more specific effect on survival than calorie restriction alone. REFERENCES 1. MELLORS, R. C., Amer. J. Clin. Pathol. 56, 270 ( 1971). 2. CASEY, T. P., J. Lab. Clin. Med. 71, 390 (1968). 3. HOROWITZ, R. E., DUFJOIS, E. L., WEINER, J., AND STRAIN, L., Lab. Invest. 21, 199 (1969). 4. CASEY, T. P., Blood 31, 396 (1968). 5. GREENWOOD, B. M., AND VOLLER, A., Clin. Exp. Immunol. 7, 793 (1970). 6. NISHIMURA, N., YASUI, M., OKAMOTO, H., KANAZAWA, M., KOTAKE, Y., AND SHIBATA, Y., Arch. Dermatol. 77, 255 (1958). 7. NISHIMURA, N., OKAMOTO, H., YASUI, M., MAEDA, K., AND OGURA, K., Arch. Dermatol. SO, 466 ( 1959). 8. CHANNIIUG, A. A., KASUGA, T., HOROWITZ, R. E., DUBOIS, E. L., AND DEMOPOULOS, H. B., Amer. J. Puthol. 47, 677 (1965). 9. SMYTHE, P. M., SCHONLAND, M., BRERETON-STILES, G. G., COOVADIA, H. M., GRACE, H. J., LOENING, W. E. K., MAFOYANE, A., PARENT, M. A., AND VOS, G. H., Lancet 939, ( 1971).
Rheumatic Disease and Department of Medicine University of Southern Los Angeles, California Received August 10,
Immunology California 90033 1972
Increased of
Free
EDMUND
L.
LORRENE
STRAIN
DUBOIS
Section
School of Medicine
Phenylalanine
a Phenylketonuric
in the
Milk
’
Mother
The genetically determined lack of phenylalanine hydroxylase in the liver of phenylketonuric (PKU) patients leads to the accumulation of phenylalanine (Phe) in their blood and tissues. Increased levels of Phe have been reported in plasma ( l-4), spinal fluid ( 1, 2) and sweat (5) of untreated individuals with phenylketonuria, but the occurrence of higher amounts of Phe in the milk of female PKU patients has not been described.
SHORT
FREE
PHENYLAL~NIN~
TABLE 1 IN THE MILK Phe (mg/lOO
Normal human (12 women) PKU subject (3 samples)
341
COMMUNICATIONS
0.20
+ 0.14 4.80
OF A PKU ml)
MOTHER Lys
(mg/lOO 0.80
ml)
+ 0.40 0.70
We have measured free Phe in the milk of a PKU mother, by the method outlined below. In addition, samples from 12 healthy females were examined for comparison purposes. Free amino acid determinations were carried out in a Hitachi-Perkin Elmer Amino-Acid Autoanalizer Mod. 034 as described by Arikawa (6). Milk samples were deproteinized and delipidized before analysis: 2 ml of milk were treated with 5 ml of a 0.1% solution of acetic acid in 65% ethyl alcohol, centrifugated at 2000g for 5 min and the supernatant was taken to dryness in vacuum (Rotavapor) below 40°C. The dry residue was dissolved with citrate buffer (pH 2.2), neutralized with 10% KOH and completely deproteinized by the addition of solid sulfosalicilic acid. After centrifugation the clear supematant was evaporated to dryness, redissolved in 2 ml of citrate buffer again and applied directly to the column. As shown in Table 1, the levels of Phe in the PKU milk are higher than those obtained from normal human milk. However, any significant difference was found in other amino acids (lysine values are also reported). These results suggest that the increase of free Phe in the milk is a direct consequence of the high plasma levels of Phe in the PKU mother (25.2 mg of free Phe per 100 ml). On the other hand, any change in the Phe content of the milk proteins can be expected. The determination of the levels of free Phe in the milk of female PKU carriers can be interesting in order to establish the possible effects on the suckling infants during the first days. REFERENCES 1. JI&VIS, G. A., BLOCK, R. J., BOLLING, D., KANZE, L., J. Biol. Chem. (1940). 2. BOREK, E., BRECHER, A., JERVIS, G. A., AND WAELSCH, H., Proc. Sot. Med. 75, 86 ( 1950). 3. LINNEWEH, F., AND EHRLICH, M., Klin. Wochenschr. 40, 225 (1962). 4. PARTINGTON, M. W., AND LEWIS, E. J. M., J. Pediut. 62, 348 ( 1963). 5. JERVIS, G. A., Proc. Exp. Biol Med. 75, 83 (1950). 6. ARIKAWA, Y., AND MAKINO, I., Fed. Proc. 25, 786 (1966).
134, Exp.
105 Biol.
342
SHORT
COMMUNICATIONS I?.
VALDIVIESO
M. MATIES M. UGARTE F. MAYOR
Depaltamento de Bioquimica Centro de Investigation de Alteraciones Molecules y Cromosdmicas Granada, Spain Received October 5, 1972
SHORT
COMMUNICATIONS
significant prolongation of life using the low-phenylalanine and lowtyrosine diet compared to the calorie-restricted group. Therefore, it appears that a low-phenylalanine and low-tyrosine diet has a more specific effect on survival than calorie restriction alone. REFERENCES 1. MELLORS, R. C., Amer. J. Clin. Pathol. 56, 270 ( 1971). 2. CASEY, T. P., J. Lab. Clin. Med. 71, 390 (1968). 3. HOROWITZ, R. E., DUFJOIS, E. L., WEINER, J., AND STRAIN, L., Lab. Invest. 21, 199 (1969). 4. CASEY, T. P., Blood 31, 396 (1968). 5. GREENWOOD, B. M., AND VOLLER, A., Clin. Exp. Immunol. 7, 793 (1970). 6. NISHIMURA, N., YASUI, M., OKAMOTO, H., KANAZAWA, M., KOTAKE, Y., AND SHIBATA, Y., Arch. Dermatol. 77, 255 (1958). 7. NISHIMURA, N., OKAMOTO, H., YASUI, M., MAEDA, K., AND OGURA, K., Arch. Dermatol. SO, 466 ( 1959). 8. CHANNIIUG, A. A., KASUGA, T., HOROWITZ, R. E., DUBOIS, E. L., AND DEMOPOULOS, H. B., Amer. J. Puthol. 47, 677 (1965). 9. SMYTHE, P. M., SCHONLAND, M., BRERETON-STILES, G. G., COOVADIA, H. M., GRACE, H. J., LOENING, W. E. K., MAFOYANE, A., PARENT, M. A., AND VOS, G. H., Lancet 939, ( 1971).
Rheumatic Disease and Department of Medicine University of Southern Los Angeles, California Received August 10,
Immunology California 90033 1972
Increased of
Free
EDMUND
L.
LORRENE
STRAIN
DUBOIS
Section
School of Medicine
Phenylalanine
a Phenylketonuric
in the
Milk
’
Mother
The genetically determined lack of phenylalanine hydroxylase in the liver of phenylketonuric (PKU) patients leads to the accumulation of phenylalanine (Phe) in their blood and tissues. Increased levels of Phe have been reported in plasma ( l-4), spinal fluid ( 1, 2) and sweat (5) of untreated individuals with phenylketonuria, but the occurrence of higher amounts of Phe in the milk of female PKU patients has not been described.
SHORT
FREE
PHENYLAL~NIN~
TABLE 1 IN THE MILK Phe (mg/lOO
Normal human (12 women) PKU subject (3 samples)
341
COMMUNICATIONS
0.20
+ 0.14 4.80
OF A PKU ml)
MOTHER Lys
(mg/lOO 0.80
ml)
+ 0.40 0.70
We have measured free Phe in the milk of a PKU mother, by the method outlined below. In addition, samples from 12 healthy females were examined for comparison purposes. Free amino acid determinations were carried out in a Hitachi-Perkin Elmer Amino-Acid Autoanalizer Mod. 034 as described by Arikawa (6). Milk samples were deproteinized and delipidized before analysis: 2 ml of milk were treated with 5 ml of a 0.1% solution of acetic acid in 65% ethyl alcohol, centrifugated at 2000g for 5 min and the supernatant was taken to dryness in vacuum (Rotavapor) below 40°C. The dry residue was dissolved with citrate buffer (pH 2.2), neutralized with 10% KOH and completely deproteinized by the addition of solid sulfosalicilic acid. After centrifugation the clear supematant was evaporated to dryness, redissolved in 2 ml of citrate buffer again and applied directly to the column. As shown in Table 1, the levels of Phe in the PKU milk are higher than those obtained from normal human milk. However, any significant difference was found in other amino acids (lysine values are also reported). These results suggest that the increase of free Phe in the milk is a direct consequence of the high plasma levels of Phe in the PKU mother (25.2 mg of free Phe per 100 ml). On the other hand, any change in the Phe content of the milk proteins can be expected. The determination of the levels of free Phe in the milk of female PKU carriers can be interesting in order to establish the possible effects on the suckling infants during the first days. REFERENCES 1. JI&VIS, G. A., BLOCK, R. J., BOLLING, D., KANZE, L., J. Biol. Chem. (1940). 2. BOREK, E., BRECHER, A., JERVIS, G. A., AND WAELSCH, H., Proc. Sot. Med. 75, 86 ( 1950). 3. LINNEWEH, F., AND EHRLICH, M., Klin. Wochenschr. 40, 225 (1962). 4. PARTINGTON, M. W., AND LEWIS, E. J. M., J. Pediut. 62, 348 ( 1963). 5. JERVIS, G. A., Proc. Exp. Biol Med. 75, 83 (1950). 6. ARIKAWA, Y., AND MAKINO, I., Fed. Proc. 25, 786 (1966).
134, Exp.
105 Biol.
342
SHORT
COMMUNICATIONS I?.
VALDIVIESO
M. MATIES M. UGARTE F. MAYOR
Depaltamento de Bioquimica Centro de Investigation de Alteraciones Molecules y Cromosdmicas Granada, Spain Received October 5, 1972