Klin. Wschr. 55, 1067-1069 (1977) Klinische

W°ch%nhrif t @) by Springer-Verlag 1977

Serum Protein-Bound Carbohydrates in Aging Men and Women

G e r d a Gnaci f l ska , K r y s t y n a Koz~owska and I rena Rawicz -Zegrzda

Department of Physiology and Department of Histology, Gdaflsk School of Medicine, Gdaflsk, Poland

Der Kohlenhydratgehalt in Giycoproteinen des menschlichen Blutplasmas in verschiedenen Lebensaltern

Zusammenfassung. In 162 m/innl ichen und 48 weibli- chen Seren wurde der Geha l t von P l a s m a p r o t e i n ge- bundenen Hexosen, A m i n o h e x o s e n und N e u r a m i n - sfiure in den verschiedenen Lebensa l t e rn untersucht . Es wurde festgestellt , dal3 bei M/ innern die genann ten K o h l e n h y d r a t a n t e i l e der Se rumglycopro te inen mi t z u n e h m e n d e m Lebensa l t e r ansteigen. Bei F r a u e n n immt nur der Ti ter von Hexosen zu, wS.hrend die A m i n o h e x o s e n und die Neuramins / iu re im Serum mit z u n e h m e n d e m Al t e r sinken. Bei F r a u e n wechsel t also der K o h l e n h y d r a t g e h a l t in den G l y c o p r o t e i n e n hauptsf ichl ich qual i ta t iv . Der Hexosengeha l t war in j e d e r A l t e r sg ruppe h6her bei F r a u e n als bei M/innern , die Neuraminsf iu re dagegen niedriger . Die A m i n o h e - xosen der G t y c o p r o t e i n e waren bei F r a u e n bis zum 30. Lebens j ah r h6her als bei Mfinnern in denselben A l t e r sg ruppen und n iedr iger bei F r a u e n in h6he rem Alter . Wi r vermuten , dab die )knderung in dem Koh- l enhydra tgeha l t der G lycop ro t e ine mi t dem wechseln- den S t e r o i d h o r m o n g e h a l t mi t z u n e h m e n d e m Al t e r ve rbunden ist.

Sehliisselw6rter: G l y c o p r o t e i n e - A m i n o h e x o s e n - Hexosen ---- Neuramins / iu re -- Alter .

Summary. C a r b o h y d r a t e c o m p o n e n t s o f serum glyco- p ro te ins were ana lysed in 162 men and 48 w o m e n of var ious age groups. Al l c o m p o n e n t s s tudied, namely amino-sugar s , hexoses and neuramin ic acid increased with age in men. In women only the hexoses level increased with age while the con ten t s o f amino - sugars and o f neuramin ic acid decreased with age, especial ly af ter the age o f 30. The s tat is t ical analysis showed tha t women had a h igher con ten t o f hexoses and a lower one o f neu ramin ic ac id than the men o f the same age groups . The a m i n o - s u g a r con ten t was h igher in w o m e n up to 30 years and lower in

Offprint requests to: Dr. Gerda Gnaciflska (address see above)

o lder w o m e n in c ompa r i son to men. It is a ssumed tha t these changes are due to changes in the s teroid h o r m o n e s with age.

Key words: Glycopro t e in s - A m i n o s u g a r s - Hex- oses - N e u r a m i n i c acid - Aging.

The conten ts o f many serum pro te ins change with age [5, 6]. Changes in serum p r o t e i n - b o u n d ca rbohy- drates , cons is t ing main ly o f amino-sugars , hexoses and neuramin ic acid however have been inves t iga ted with vary ing results [1, 2, 1 I]. In our prev ious experi- ments we suggested tha t an increas ing e ry th rocy te sed imen ta t ion rate in ag ing men and a decreas ing one in aging w o m e n m a y be connec ted with changes in serum g lycopro te in concen t r a t ions [4]. Thus we a t t e m p t e d to invest igate i f and how a change occurs with age in se rum p r o t e i n - b o u n d ca rbohydra t e s .

Materials and Methods

Human serum was obtained from 162 healthy male blood donars of 18 to 58 years of age and 48 women, mostly donars aged between 17-55 years. The following carbohydrate components of serum proteins were determined:

1. Amino-sugars by the Elson-Morgan method with Gardell modification [3]. Glucosamine (HC1) Sigma was used as a standard.

2. Hexoses by the antron method according to Shields and Burnett [I9]. The standard was glucose (Koch-Light).

3. Neuraminic acid by the method according to Saifer, Gersten- feld and Brooklyn [14]. The standard used was N-acetylo-neurami- nic acid (Sigma).

The subjects were divided into 4 age groups, results were ana- lysed statistically.

Results

The course o f the changes in the pa r t i cu l a r com- ponen ts o f se rum c a r b o h y d r a t e s con ten t s differs in bo th men and women. In men a gradual , s low increase occur r ing with age was observed for all the ca rbohy-

1068 G. Gnacifiska et al. : Protein-Bound Carbohydrates and Age

Table 1, Content of serum glycoprotein components in various age groups in men (rag/100 ml)

Age Amiuosugars Hexoses Neuraminic acid groups

S

n x ± S n x_+S n x ± S n x i S

I8-19 30 90.8 ± 17.6 29 154.0±41.8 31 73.8 ± 7.7 24 20-29 32 101.2 +_ 16.7 57 141.7 _+43.4 59 78.7 +_21.9 31 30-39 30 105,8 +_ 19.8 39 165.4-+ 43.3 40 74.5 _4-14.4 26 4 ~ 5 8 25 107.3 ± 15.6 29 168.2+28.2 32 83.1 ± 19.6 24

Total 117 101.0± 6.4 154 155 .0± t l . 2 162 7 Z 6 ± 3.9 105

330.2_+34.8 350.6±43.4 355.6_+51.1 354.8±40,3

348.2±43.2

x = m e a n value, n = n u m b e r of persons, S = S t a n d a r d deviation, X = s u m of glycoprotein components

Table 2. Content of serum glycoprotein components in various age groups in women (rag/100 ml)

Age Aminosugars Hexoses Neuraminic acid groups

n x ± S n x ± S n x ± S

Z

n x ± S

17-20 11 109.9 ± 14.4 13 168.0 ± 23.5 14 71.6 ± 9.0 21-30 11 111.5_+13.3 11 167.6±30.7 11 71.7± 7.3 31-40 14 102.0±10.5 18 179.3±24.8 17 67.7± 7,6 41--55 6 94.8 ± 14.5 6 191.8 _+ 48.2 6 67~3 ± 13.3

Total 42 105.6 +_ 13.7 48 175.2 ± 29.0 48 69,7 ± 8.7

11 11 14 6

42

351.6+_25.7 350.9 ± 37,0 350.2 ± 30.7 354.0 ± 55.4

351.3±33.7

x = mean value, N = number of persons, S = Standard deviation, ~ = sum

drate components investigated. The coefficient of cor- relation between age and contents of aminosugars, hexoses and neuraminic acid are 0.94, 0.97 and 0.94. The results are statistically significant (p below 0.001). The most evident was the increase of aminosugar contents (18%). The total sum of carbohydrate com- ponents of serum protein (aminosugars+hexoses +neuraminic acid) increases f rom 330 mg% at 18-19 years to 355 rag% in the group of men aged between 50 and 58 years (Table 1).

In women, the course and dynamics of the changes differ f rom those in men. Up to the age of 30, there are no evident changes in the contents of the investi- gated carbohydrate serum protein components. After the age of 30, a definite decrease in the contents of aminosugars is observed, a tess noticeable decrease of neuraminic acid takes place, while the contents of hexoses, as in men, increase with age. The coeffi- cients of correlation between age and contents of ami- nosugars, hexoses and neuraminic acid correspond to 0.85, 0.90 and 0.88. They are statistically significant (p less than 0.001). The total sum of carbohydrate serum protein components in women does not change with age. This is a consequence of the decrease in aminosugar and neuraminic acid contents with age and a simultaneous increase of hexoses. Therefore, it seems that especially the qualitative composition of carbohydrate components of serum glycoproteins change in women (Table 2).

Comparing the contents of the particular carbohy-

drate serum protein components in men and women of a same age, we notice a higher level of hexoses and a lower one of neuraminic acid in women than in men, while the aminosugar contents that are higher in women up to the age of 30 decrease in older groups to lower values than in men.

Discussion

The results obtained in our studies agree partly with those of other authors. B6ttiger et al. found an evi- dent increase only in the contents of neuraminic acid with age, both in men and women [1; 21. These au- thors did not find noticeable differences in the con- tents of serum protein-bound carbohydrates in men and women. Laskowski et al. [11] analysing the con- tens of serum protein-bound carbohydrates in men and women observed a slight increase of all these elements in both sexes without any distinct differences between them.

The results of our investigations indicate an in- crease of all glycoprotein components in men alone. In women an increase of hexoses only was observed, while with age a distinct decrease shows in the con- tents of aminosugars and neuraminic acid. In the in- vestigations of B6ttiger et al. [1, 2] the differences might be due to the different populations studied. The serum proteins vary phenotypically in different populations similarly to blood groups [15, 16, 17].

G. Gnacifiska et al.: Protein-Bound Carbohydrates and Age 1069

The change with age in contents of serum protein- bound carbohydrates probably depends on changes of glycoprotein synthesis. The increased contents of all elements of serum protein-bound carbohydrates found in men may indicate increased concentrations of particular serum glycoproteins and/or the emer- gence of a new glycoprotein. The concentration of some serum glycoproteins changes with age. An in- creased concentration of alfa 2 macroglobulin, alfa 1 antitrypsin [5], IgA and IgG [6] may be observed, for example, in men and in women. The change in composition of carbohydrate components in women above 30 years would rather indicate the appearance of new glycoproteins.

The influence of male and female sex hormones on the anabolism of proteins and on the increase of glycoprotein contents in serum is well known. An increase of alfa 2 globulin in serum was noted, for example, following injections of androgen steroids in human beings [13, 20, 21] and increase of alfa 1 globu- lin after estrogens [20]. In experimental animals changes in serum glycoprotein contents were seen fol- lowing injections of sex hormones or after an orchiec- tomy or ovariectomy [7]. The effect of cortisol which raises the level of cell glycoproteins by stimulating their synthesis is also known [8, 9, 10].

The concentration of steroid hormones changes with age. In women a lower estrogen secretion already begins in the third decade of life and is more intensely noticeable after the menopause. The contents of corti- sol [18] and androgens also get lower. In men the content of free testosteron in serum decreases [12], accompanied by a simultaneous increase in contents ofcortisol [18] and estrogens. In healthy men of 45-65 years, the urinary excretion of estrogens is almost twice that observed in younger men and definitely higher than in women following menopause. We pre- sume that with aging the changes in contents of ste- roid hormones, which are important in protein syn- thesis, may effect quantitative and qualitative changes of serum glycoproteins.

The fact of the existing similarity in the curve of increasing concentrations of all analysed glyco- protein carbohydrates in aging men and in the curve of the erythrocyte sedimentation rate [4] is most note- worthy, and it is possible that a causal relation be- tween them is present. In aging women a similarity only appears between the curve of aminosugars and neuraminic acid changes with age and the curve of erythrocyte sedimentation rate with age.

References

1. B6ttiger, L.E., Carlson, L.A.: Serum glucoprotein concentra- tion in normal men. Clin. Chim. Acta 5, 664 (1960)

2. B6ttiger, L.E,, Halmstrom, A. : Serum protein-bound carbohy- drates in normal women. J. Lab. Clin. Med. 63, 772 (1964)

3. Gardell, S. : Determination of hexosamines. Methods Biochem- ical Analysis Interscience Publ. INC. N. York 8, 42 (1968)

4. Gnacifiska, G.: Age and sex and erythrocyte sedimentation rate (in Polish). Pol. Tyg. Lek. 27, 1198 (1972)

5. Hamilton, P.J., Dawson, A.A., Ogston, D., Douglas, A.S.: The effect of age on the fibrinolytic enzyme system. J. Clin. Path. 27, 326 (I974)

6. Heide, K., Schwick, H.G.: Immunobiologische Aspekte des Blutes. Naturwissenschaften 57, 184 (1970)

7. Houssay, A.B., Blumenkrantz, N.: Changes in glycoproteins in Serum, urine and aqueous humor after gonadectomy or sex hormone injections in rats. Endocrinology 74, 825 (1964)

8. Koztowska, K., Zurawska-Czupa, B. : The effect of corticotrop- ine and cortisone on the content of fucose in the stomach mucosa of white rats. Endocrinologie 55, 349 (1969)

9. Kozlowska, K.: The effect of ACTH and cortisone on some glycoprotein components in the stomach mucosa of rats (in Polish). Patologia Polska 22, 505 (1971)

10. Koztowska, K.: Investigations on the effect of ACTH and cortisone on the carbohydrate-protein complexes in the stom- ach mucosa of white rats (in Polish). Ann. Acad. Med. Gedan. 2, 9 (1972)

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12. Nieschlag, E., Kley, H . K , Wiegelmann, W., Solbach, H.G., Kruskemper, H.L.: Lebensalter und endocrine Funktion der Testes des erwachsenen Mannes. Dtsch. Med. Wschr. 98, 1281 (1973)

13. Sachs, B.A., Danielson, E., Weston, R.E.: Effect of the syn- thetic anabolic steroid, 17-ethyl 19 nortestosterone on serum proteins, lipoproteins and lipids in human subjects. J. C1in. Endocrinol. 16, 1388 (I956)

14. Saifer, A., Gerstenfeld, S., Brooklyn, N.Y.: The serum neura- minic acid distribution. I Methodology. J. Lab. Clin. Med. 50, 17 (1957)

i5. Schlesinger, D. : Hp subgroups in the Polish population. Arch. Immunol. Therap. Exper. 19, 671 (1971)

16. Schlesinger, D., Halasa, J., D~ongowska-Dzongu, T.: Fre- quency of types in the Hp, Gc and Gm serum systems and acid phosphatase of erythrocytes in the Gl~ek population. Ibid. 679

17. Schlesinger, D., Luczkiewicz,-Mulczykowa A.: The Gm (1), Gm (2) and Gm (4) factors in the Polish population. Ibid. 703

18. Shou, J., Jansen, J., Hvidberg, E.: Decreased concentration of tissue cortisol in the menopause by a new micromethod. Nature 215, 202 (1967)

19. Shields, R., Burnett, W. : Determination of protein-bound car- bohydrate in serum by a modified antrone method. Anal. Chem. 32, 885 (1960)

20. v. Studnitz, W., Berezin, D. : Das Verhalten der elektrophoreti- schen Proteint~aktionen im Serum yon Franen nach Gaben von androgenen und 6strogenen Hormonen. Klin. Wschr. 34, 1239 (1956)

21. v. Studnitz, W., Nyman, M.: Effect of androgens on alfa2- globulins in women. J. Clin. EndocrinoL 17, 910 (1957)

Dr. Gerda Gnacifiska Dept of Physiology Gdafisk School of Medicine Debinki 1 80-211 Gdafisk/Polen