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Observations on the Biochemistry of Human Semen. 4. Cholesterol
..,...
Vol. 21, No. I, January 1970 Printed in U.S.A.
FERTILITY AND STERILITY
Copyright
© 1970 by The Williams & Wilkins Co.
OBSERVATIONS ON THE BIOCHEMISTRY OF HUMAN SEMEN. 4. CHOLESTEROL K. H. MOON, M.D.,
AND
R. G. BUNGE, M.D.
Department of Urology, University of Iowa College of Medicine, Iowa City, Iowa
The possible significance of cholesterol in the metabolism of the spermatozoa is not known. In 1935, Goldblatt3 reported that the concentration of cholesterol in human seminal plasma was 80 mg.j100 ml. In 1942, Swyer 9 observed that the adenomatous part of hypertrophic prostate glands contains about twice as much cholesterol as does normal tissue. Eliasson,2 in 1966, reported that mean concentration of cholesterol in human seminal plasma was 46.8 mg./100 ml. The observations herein described were undertaken to determine whether any correlation existed between concentration of cholesterol and various qualities of semen. Furthermore, evaluation of the androgenic effect on cholesterol production in the accessory glands and a comparison of cholesterol levels in normal and abnormal prostatic secretions were undertaken.
The final mixture was centrifuged and the clear supernatant was read in the Turner's fluorometer. I, 7 RESULTS
It should be emphasized that our classification of semen quality by counts, etc., is an arbitrary one and it was described in a preceding paper.4 Cholesterol Value in Normal Semen. In Table 1, sperm counts are classified into four groups: (1) known fertile group (sperm counts are above 20 million/mI.); (2) 20--40 million/ml.; (3) 40-60 million/ ml.; and (4) over 60 million/ml. The range of cholesterol in normal group showed a wide range from 16-94 mg.j100 ml.; an average value was 45 mg./100 ml. There is no significant correlation between the value of cholesterol and the sperm counts. Cholesterol Value in Abnormal Semen. In Table 2, several conditions were included in the study such as: (1) oligospermia; below 20 million/ml.; (2) azoospermia; (3) postvasectomy azoospermia; (4) Klinefelter's syndrome azoospermia. The range of cholesterol in these groups showed a wide range from 17-80 mg.j100 ml. with an average value of 45 mg./100 ml. The level of cholesterol was not correlated to the number of spermatozoa or any other abnormal findings in the semen. Although the average value of cholesterol in Klinefelter's syndrome was slightly higher than others, there was no significant statistical difference from other groups. Consistency of Cholesterol Value in the Same Individual. In Table 3, 3 normal persons were studied. The range of cholesterol
MATERIALS AND METHODS
Three hundred ten patients coming to the infertility clinic produced semen samples by masturbation after a minimum of 3 days' continence. Routine examination included volume, liquefaction time, counts in million per milliliter, viability, and abnormal forms. Activity was judged subjectively. After centrifugation, the supernatants were used for this study. The fluorometric method was used for the measurement of total seminal cholesterol, based on the Lieberman-Burchard reaction. To 20 fLl. of supernatants were added a 3: 2 mixture of acetic acid and chloroform and a 10: 3 mixture of chloroform and acetic anhydride followed by sulfuric acid. 80
January 1970
TABLE 1. The Level of Cholesterol in Normal Semen No. of samples
S~:~:
20' 86 30 48
million/ mi. >20 20-40 40-60 >60
Cholesterol concentration Range
Mean Total (184)
81
BIOCHEMISTRY OF HUMAN SEMEN. 4
Average
mg./lOO ml.
Cholesterol content in total ejaculates Range
Average
mg.
20-89 20-94 22-81 16-76
43 45 47 43
0.3-4.5 0.4-3.3 0.2-2.8
1.5 1.6 1.4
16-94
45
0.2-4.5
1.5
• Known fertile male; sperm counts are above 20 million/ml
in M ..J. was 20-33 mg./IOO ml. while the fructose range was 204-285 mg/IOO ml. The range of cholesterol in O. B. was 26-50 mg/IOO ml. while fructose ranged from 564-660 mg./l00 ml. M. Y. showed a range of cholesterol from 54-74 mg/IOO ml. while fructose was from 152-217 mg./IOO ml. There was considerable fluctuation of cholesterol in the same individual as well as fluctuation of fructose .. Also, there was no quantitative correlation between the level of fructose and cholesterol. Cholesterol Level in Seminal Plasma and Blood Testosterone. In Table 4, 2 Klinefelter's patients were studied. In C. L. the level of cholesterol at precastration was 62 mg·/l00 ml. with subnormal blood testosterone (normal male testosterone: 044-1.0 p.gm./100 ml.). Cholesterol level at 8 weeks after castration remained the same as the precastrated level in spite of no detectable amounts of blood testosterone. After 12 weeks of testosterone treatment, cholesterol level dropped to 24 mg/100 ml. In L. P. the level of cholesterol, precastration, was 66 mg/100 ml. with an extremely low level of blood testosterone. There was a level of 27 mg/IOO ml. of cholesterol at 8 weeks after castration with no detectable blood testosterone and 63 mg/l00 ml. of cholesterol at 12 weeks during testosterone therapy. In both cases, blood testosterones were at normal male levels at 12 weeks during therapy. It is evident also that the fruc-
tose level dropped to a trace level after castration, but there was no effect on the production of cholesterol in seminal fluid in the absence of testosterone. It is evident that contradictory values of cholesterol were obtained, one showing a decrease after castration and the other indicating a decrease after testosterone treatment. The Level of Cholesterol in Normal and Abnormal Prostatic Secretion. In Table 5, in 12 patients who had acute or chronic prostatitis cholesterol levels in prostatic secretions ranged from 103-198 mg./IOO ml. The average was 148 mg/100 ml. Normal prostatic secretion obtained from 6 subjects showed that the range was 26-76 mg/IOO ml. and the average was 58 mg/ 100 ml. Prostatic secretion in prostatitis contained significantly higher cholesterol levels than in secretions 0 f the normal prostates. TABLE 2. Tf"e, Level of Cholesterol in Abnormal Semen No. of samples
Sperm count
million/mi. 81 22 13 10
Below 20 Azoospermia Postvasectomy azoospermia Klinefelter's
Cholesterol concentration
Cholesterol content in total ejaculates
Range Average
Range
mg./JOO mi.
Average
mg.
17-80 18-58 25-65
42 40 44
0.2-4.4 0.2-3.3 0.3-1.7
1.5 1.3 0.7
39-66
54
0.3-2.2
0.7
17-80
45
0.2-4.4
1.1
syndrome Azoospermia
Mean Total (126)
TABLE 3. Individual Variation of Seminal Cholesterol in Known Fertile Males Sample 1 Patients Choles- Fructose terol mg./lOO ml
M.J. O.B. M. Y.
29 33 67
285 660 217
Sample 2
Sample 3
Choles- Fructerol tose
Choles- Fructerol tose
mg./JOO mi.
mg./JOO mi.
33 50 54
264 564 152
20 26 74
204 588 156
T
82
Vol. 21
MOON AND BUNGE
TABLE 4. The Level of Seminal Cholesterol in Pre- and Postcastration and during Androgenic Treatment in 2 PatieTl.ts with Klinefelter's Syndrome T
C' mg.
C. L. L. P.
62 66
%
Pog.%
0.27 0.057
On hormonal therapy (12 weeks)
Postcastration (8 weeks)
Precastration
Patients
F mg.
C
%
mg.
%
62 27
285 144
T
F
Pog· %
mg.%
N.D. N.D.
24 12
T
C mg.
%
24
63
Pog.%
0.439 0.414
F mg.
%
240 165
* C, cholesterol; T, testosterone; F, fructose. TABLE 5. The Level of Cholesterol in Normal Prostatic Secretions and Prostatic Secretions Obtained from Patients with Acute or Chronic prostatitis No. of cases
Cholesterol Clinical diagnosis
Range
Average
mg.jlOO ml.
12 Acute or chronic prosta- 103-198 titis 6 Normal prostate
26-76
148 58
DISCUSSION
The average cholesterol level in the seminal plasma was reported differently as 80 mg.j100 ml. by Goldblatt,S 70-120 mg.j100 ml. by Scott,S and 46.8 mg.jml. by Eliasson. 2 It was agreed that the origination of cholesterol in the seminal plasma was mainly derived from the prostate gland. In our results, the average of cholesterol in the normal group was 45 mg./100 ml. and ranged from 16-94 mg./100 ml. The average in the abnormal group was 45 mg.j100 ml. and ranged from 17-80 mg./100 ml. There was no correlation between the level of cholesterol and the various semen qualities. It is, therefore, presumed that cholesterol in the seminal plasma plays no significant role in sperm metabolism. However, it has been suggested that the lipoproteins in semen may act as protective colloids for the sperm cells and lipids themselves do not seem to influence the sperm metabolism. 5 In order to evaluate the hormonal effect on cholesterol production, we observed the concentration of cholesterol in the seminal plasma of 2 patients with
Klinefelter's syndrome in the pre-, postcastration, and during testosterone treatment periods. There was no hormonal influence on the production of cholesterol. This was also confirmed by our observation on the value of seminal cholesterol before and after androgenic or estrogenic therapy on oligospermic patients. 6 A sharp elevation of cholesterol in the prostatic secretion in acute or chronic prostatitis is a significant finding compared to the value in normal prostatic secretion. Swyer,9 in 1942, reported that the concentration of cholesterol in the enlarged prostate is higher than that of normal prostate. Although the mechanism of cholesterol formation in the prostate is not clear, its level in the prostatic secretion might be a useful indicator for the evaluation of prostatic lesions. SUMMARY
1. The cholesterol level of human seminal plasma has been estimated in 310 patients. The average concentrations were 45 mg.j100 ml. (range 16-94) in normal semen and 45 mg./100 ml. (range 17-80) in abnormal semen. There was no correlation between the cholesterol concentration and the various semen qualities. 2. There is a suggestion that the level of cholesterol in seminal plasma was not altered by endogenous or exogenous androgenic hormone. 3. In prostatitis, the concentration of cholesterol in the prostatic secretion was significantly higher than in the normal prostatic secretion.
January 1970
BIOCHEMISTRY OF HUMAN SEMEN. 4
REFERENCES 1. ALBERS, R. W., AND LOWRY, O. H. Fluorometric
2. 3. 4.
5.
determination of 0.1 to 10 micrograms of cholesterol. Anal Chem 27 :1829,1955. ELIASSON, R. Cholesterol in human semen. Biochem J 98 :242, 1966. GOLDBLATT, M. W. Constituents of human seminal plasma. Biochem J 29:1346,1935. MOON, K. H., AND BUNGE, R. G. Observations on the biochemistry of human semen. 1. Fructose. Fertil Steril19 :186, 1968. MANN, T. Biochemistry of Semen and of the
6. 7.
8.
9.
83
Male Reproductive Tract. Methuen, London. 1964. MOON, K. H., AND BUNGE, R. G. Unpublished data. PHILLIPS, R. E. "Total Serum Cholesterol." In Manual of Fluorometric Chemical Procedures. G. K. Turner Associations, Inc., Palo Alto, Calif., 1966. SCOTT, W. W. The lipids of the prostatic fluid, seminal plasma and enlarged prostate gland of man. J Urol 53 :712, 1945. SWYER, G. 1. M. The cholesterol content of normal and enlarged prostates. Cancer Res 2 :372, 1942.
Vol. 21, No. I, January 1970 Printed in U.S.A.
FERTILITY AND STERILITY
Copyright
© 1970 by The Williams & Wilkins Co.
OBSERVATIONS ON THE BIOCHEMISTRY OF HUMAN SEMEN. 4. CHOLESTEROL K. H. MOON, M.D.,
AND
R. G. BUNGE, M.D.
Department of Urology, University of Iowa College of Medicine, Iowa City, Iowa
The possible significance of cholesterol in the metabolism of the spermatozoa is not known. In 1935, Goldblatt3 reported that the concentration of cholesterol in human seminal plasma was 80 mg.j100 ml. In 1942, Swyer 9 observed that the adenomatous part of hypertrophic prostate glands contains about twice as much cholesterol as does normal tissue. Eliasson,2 in 1966, reported that mean concentration of cholesterol in human seminal plasma was 46.8 mg./100 ml. The observations herein described were undertaken to determine whether any correlation existed between concentration of cholesterol and various qualities of semen. Furthermore, evaluation of the androgenic effect on cholesterol production in the accessory glands and a comparison of cholesterol levels in normal and abnormal prostatic secretions were undertaken.
The final mixture was centrifuged and the clear supernatant was read in the Turner's fluorometer. I, 7 RESULTS
It should be emphasized that our classification of semen quality by counts, etc., is an arbitrary one and it was described in a preceding paper.4 Cholesterol Value in Normal Semen. In Table 1, sperm counts are classified into four groups: (1) known fertile group (sperm counts are above 20 million/mI.); (2) 20--40 million/ml.; (3) 40-60 million/ ml.; and (4) over 60 million/ml. The range of cholesterol in normal group showed a wide range from 16-94 mg.j100 ml.; an average value was 45 mg./100 ml. There is no significant correlation between the value of cholesterol and the sperm counts. Cholesterol Value in Abnormal Semen. In Table 2, several conditions were included in the study such as: (1) oligospermia; below 20 million/ml.; (2) azoospermia; (3) postvasectomy azoospermia; (4) Klinefelter's syndrome azoospermia. The range of cholesterol in these groups showed a wide range from 17-80 mg.j100 ml. with an average value of 45 mg./100 ml. The level of cholesterol was not correlated to the number of spermatozoa or any other abnormal findings in the semen. Although the average value of cholesterol in Klinefelter's syndrome was slightly higher than others, there was no significant statistical difference from other groups. Consistency of Cholesterol Value in the Same Individual. In Table 3, 3 normal persons were studied. The range of cholesterol
MATERIALS AND METHODS
Three hundred ten patients coming to the infertility clinic produced semen samples by masturbation after a minimum of 3 days' continence. Routine examination included volume, liquefaction time, counts in million per milliliter, viability, and abnormal forms. Activity was judged subjectively. After centrifugation, the supernatants were used for this study. The fluorometric method was used for the measurement of total seminal cholesterol, based on the Lieberman-Burchard reaction. To 20 fLl. of supernatants were added a 3: 2 mixture of acetic acid and chloroform and a 10: 3 mixture of chloroform and acetic anhydride followed by sulfuric acid. 80
January 1970
TABLE 1. The Level of Cholesterol in Normal Semen No. of samples
S~:~:
20' 86 30 48
million/ mi. >20 20-40 40-60 >60
Cholesterol concentration Range
Mean Total (184)
81
BIOCHEMISTRY OF HUMAN SEMEN. 4
Average
mg./lOO ml.
Cholesterol content in total ejaculates Range
Average
mg.
20-89 20-94 22-81 16-76
43 45 47 43
0.3-4.5 0.4-3.3 0.2-2.8
1.5 1.6 1.4
16-94
45
0.2-4.5
1.5
• Known fertile male; sperm counts are above 20 million/ml
in M ..J. was 20-33 mg./IOO ml. while the fructose range was 204-285 mg/IOO ml. The range of cholesterol in O. B. was 26-50 mg/IOO ml. while fructose ranged from 564-660 mg./l00 ml. M. Y. showed a range of cholesterol from 54-74 mg/IOO ml. while fructose was from 152-217 mg./IOO ml. There was considerable fluctuation of cholesterol in the same individual as well as fluctuation of fructose .. Also, there was no quantitative correlation between the level of fructose and cholesterol. Cholesterol Level in Seminal Plasma and Blood Testosterone. In Table 4, 2 Klinefelter's patients were studied. In C. L. the level of cholesterol at precastration was 62 mg·/l00 ml. with subnormal blood testosterone (normal male testosterone: 044-1.0 p.gm./100 ml.). Cholesterol level at 8 weeks after castration remained the same as the precastrated level in spite of no detectable amounts of blood testosterone. After 12 weeks of testosterone treatment, cholesterol level dropped to 24 mg/100 ml. In L. P. the level of cholesterol, precastration, was 66 mg/100 ml. with an extremely low level of blood testosterone. There was a level of 27 mg/IOO ml. of cholesterol at 8 weeks after castration with no detectable blood testosterone and 63 mg/l00 ml. of cholesterol at 12 weeks during testosterone therapy. In both cases, blood testosterones were at normal male levels at 12 weeks during therapy. It is evident also that the fruc-
tose level dropped to a trace level after castration, but there was no effect on the production of cholesterol in seminal fluid in the absence of testosterone. It is evident that contradictory values of cholesterol were obtained, one showing a decrease after castration and the other indicating a decrease after testosterone treatment. The Level of Cholesterol in Normal and Abnormal Prostatic Secretion. In Table 5, in 12 patients who had acute or chronic prostatitis cholesterol levels in prostatic secretions ranged from 103-198 mg./IOO ml. The average was 148 mg/100 ml. Normal prostatic secretion obtained from 6 subjects showed that the range was 26-76 mg/IOO ml. and the average was 58 mg/ 100 ml. Prostatic secretion in prostatitis contained significantly higher cholesterol levels than in secretions 0 f the normal prostates. TABLE 2. Tf"e, Level of Cholesterol in Abnormal Semen No. of samples
Sperm count
million/mi. 81 22 13 10
Below 20 Azoospermia Postvasectomy azoospermia Klinefelter's
Cholesterol concentration
Cholesterol content in total ejaculates
Range Average
Range
mg./JOO mi.
Average
mg.
17-80 18-58 25-65
42 40 44
0.2-4.4 0.2-3.3 0.3-1.7
1.5 1.3 0.7
39-66
54
0.3-2.2
0.7
17-80
45
0.2-4.4
1.1
syndrome Azoospermia
Mean Total (126)
TABLE 3. Individual Variation of Seminal Cholesterol in Known Fertile Males Sample 1 Patients Choles- Fructose terol mg./lOO ml
M.J. O.B. M. Y.
29 33 67
285 660 217
Sample 2
Sample 3
Choles- Fructerol tose
Choles- Fructerol tose
mg./JOO mi.
mg./JOO mi.
33 50 54
264 564 152
20 26 74
204 588 156
T
82
Vol. 21
MOON AND BUNGE
TABLE 4. The Level of Seminal Cholesterol in Pre- and Postcastration and during Androgenic Treatment in 2 PatieTl.ts with Klinefelter's Syndrome T
C' mg.
C. L. L. P.
62 66
%
Pog.%
0.27 0.057
On hormonal therapy (12 weeks)
Postcastration (8 weeks)
Precastration
Patients
F mg.
C
%
mg.
%
62 27
285 144
T
F
Pog· %
mg.%
N.D. N.D.
24 12
T
C mg.
%
24
63
Pog.%
0.439 0.414
F mg.
%
240 165
* C, cholesterol; T, testosterone; F, fructose. TABLE 5. The Level of Cholesterol in Normal Prostatic Secretions and Prostatic Secretions Obtained from Patients with Acute or Chronic prostatitis No. of cases
Cholesterol Clinical diagnosis
Range
Average
mg.jlOO ml.
12 Acute or chronic prosta- 103-198 titis 6 Normal prostate
26-76
148 58
DISCUSSION
The average cholesterol level in the seminal plasma was reported differently as 80 mg.j100 ml. by Goldblatt,S 70-120 mg.j100 ml. by Scott,S and 46.8 mg.jml. by Eliasson. 2 It was agreed that the origination of cholesterol in the seminal plasma was mainly derived from the prostate gland. In our results, the average of cholesterol in the normal group was 45 mg./100 ml. and ranged from 16-94 mg./100 ml. The average in the abnormal group was 45 mg.j100 ml. and ranged from 17-80 mg./100 ml. There was no correlation between the level of cholesterol and the various semen qualities. It is, therefore, presumed that cholesterol in the seminal plasma plays no significant role in sperm metabolism. However, it has been suggested that the lipoproteins in semen may act as protective colloids for the sperm cells and lipids themselves do not seem to influence the sperm metabolism. 5 In order to evaluate the hormonal effect on cholesterol production, we observed the concentration of cholesterol in the seminal plasma of 2 patients with
Klinefelter's syndrome in the pre-, postcastration, and during testosterone treatment periods. There was no hormonal influence on the production of cholesterol. This was also confirmed by our observation on the value of seminal cholesterol before and after androgenic or estrogenic therapy on oligospermic patients. 6 A sharp elevation of cholesterol in the prostatic secretion in acute or chronic prostatitis is a significant finding compared to the value in normal prostatic secretion. Swyer,9 in 1942, reported that the concentration of cholesterol in the enlarged prostate is higher than that of normal prostate. Although the mechanism of cholesterol formation in the prostate is not clear, its level in the prostatic secretion might be a useful indicator for the evaluation of prostatic lesions. SUMMARY
1. The cholesterol level of human seminal plasma has been estimated in 310 patients. The average concentrations were 45 mg.j100 ml. (range 16-94) in normal semen and 45 mg./100 ml. (range 17-80) in abnormal semen. There was no correlation between the cholesterol concentration and the various semen qualities. 2. There is a suggestion that the level of cholesterol in seminal plasma was not altered by endogenous or exogenous androgenic hormone. 3. In prostatitis, the concentration of cholesterol in the prostatic secretion was significantly higher than in the normal prostatic secretion.
January 1970
BIOCHEMISTRY OF HUMAN SEMEN. 4
REFERENCES 1. ALBERS, R. W., AND LOWRY, O. H. Fluorometric
2. 3. 4.
5.
determination of 0.1 to 10 micrograms of cholesterol. Anal Chem 27 :1829,1955. ELIASSON, R. Cholesterol in human semen. Biochem J 98 :242, 1966. GOLDBLATT, M. W. Constituents of human seminal plasma. Biochem J 29:1346,1935. MOON, K. H., AND BUNGE, R. G. Observations on the biochemistry of human semen. 1. Fructose. Fertil Steril19 :186, 1968. MANN, T. Biochemistry of Semen and of the
6. 7.
8.
9.
83
Male Reproductive Tract. Methuen, London. 1964. MOON, K. H., AND BUNGE, R. G. Unpublished data. PHILLIPS, R. E. "Total Serum Cholesterol." In Manual of Fluorometric Chemical Procedures. G. K. Turner Associations, Inc., Palo Alto, Calif., 1966. SCOTT, W. W. The lipids of the prostatic fluid, seminal plasma and enlarged prostate gland of man. J Urol 53 :712, 1945. SWYER, G. 1. M. The cholesterol content of normal and enlarged prostates. Cancer Res 2 :372, 1942.