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Growth Hormone Releasing Hormone Test for Infertile Men With Spermatogenetic Maturation Arrest
0022-5347/02/1685-2083/0 THE JOURNAL OF UROLOGY® Copyright © 2002 by AMERICAN UROLOGICAL ASSOCIATION, INC.®
Vol. 168, 2083–2085, November 2002 Printed in U.S.A.
DOI: 10.1097/01.ju.0000034265.27750.49
GROWTH HORMONE RELEASING HORMONE TEST FOR INFERTILE MEN WITH SPERMATOGENETIC MATURATION ARREST MASATO FUJISAWA, KUNITO YAMANAKA, HIROSHI OKADA, SOICHI ARAKAWA AND SADAO KAMIDONO From the Division of Urology, Department of Organs Therapeutics, Kobe University Graduate School of Medicine, Kobe, Japan
ABSTRACT
Purpose: Growth hormone has an important role in the function of the male reproductive system. We investigated infertile men with impaired growth hormone secretion. Materials and Methods: Growth hormone status was studied in 8 fertile men and 9 infertile men with azoospermia due to spermatogenetic maturation arrest. Growth hormone releasing hormone, the specific stimulatory neurohormone, was used in the growth hormone stimulation test. A dose of 100 g. of growth hormone releasing hormone was infused intravenously and serum growth hormone concentrations were measured at 0, 15, 30, 60, 90 and 120 minutes. Serum follicle-stimulating hormone, luteinizing hormone, prolactin, testosterone and estradiol were also measured before the test. Results: Serum follicle-stimulating hormone concentrations were significantly increased in the azoospermic group and basal levels of growth hormone were similar to those in the control group. Serum growth hormone concentrations increased after injection of growth hormone releasing hormone and the levels of growth hormone peaked after 30 minutes in both groups. At time 30 minutes growth hormone levels had decreased significantly more in the azoospermic group than in the controls. Men with azoospermia due to spermatogenetic maturation arrest had a low response to the growth hormone releasing hormone test. Conclusions: Relative growth hormone insufficiency, which may be caused by reduced reactivity to growth hormone releasing hormone in pituitary growth hormone secretory cells, is strongly related to spermatogenic dysfunction. KEY WORDS: somatotropin; somatotropin-releasing hormone; spermatogenesis; sperm maturation
Growth hormone has a role in pubertal development of male and female functions and somatic growth. It has been reported that patients with isolated growth hormone deficiency have a significantly delayed puberty and that the size of the testes and penis increased after growth hormone treatment.1, 2 Among men with isolated growth hormone deficiency due to neurosurgery, treatment with growth hormone increased levels of serum testosterone and volume of seminal plasma.3 Several studies have demonstrated by classical stimulating tests (arginine or clonidine) that growth hormone secretion is impaired in infertile men.4, 5 We evaluate growth hormone status in infertile men with spermatogenetic maturation arrest and used growth hormone releasing hormone as the specific stimulatory neurohormone.
and 120 minutes. Before the test serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin were assayed by chemiluminescence. Testosterone and estradiol concentrations were measured by radioimmunoassay. Serum was separated and stored at ⫺20C until it was assayed. Serum growth hormone concentrations were determined by immunoradiometric assay. Statistical evaluations were performed using the nonparametric Mann-Whitney U test to reveal differences between the control and azoospermic groups. Possible correlations were tested by Pearson’s correlation coefficients, with p ⬍0.05 considered significant.
RESULTS MATERIALS AND METHODS
This study included 9 men with a mean age ⫾ SD of 33.1 ⫾ 4.1 years (range 28 to 40) with nonobstructive azoospermia and testicular biopsy proven spermatogenetic maturation arrest, and 8 healthy fertile volunteers with a mean age ⫾ SD of 29.6 ⫾ 3.8 years (25 to 35) with normal seminograms who served as controls. None of the men with azoospermia had received any medication for male infertility before the study. All patients were subjected to the same study after informed consent was obtained. Each patient arrived at the hospital at 9:00 a.m. following an overnight fast and was placed in the supine position. A cannula was inserted into the antecubital vein and 100 g. per body of growth hormone releasing hormone was infused intravenously after a 30-minute rest period. Serum growth hormone concentrations were measured at 0, 15, 30, 60, 90 Accepted for publication May 24, 2002.
Serum FSH concentrations were significantly increased in the azoospermic group compared to those in the control group. Serum LH, prolactin, testosterone and estradiol concentrations in the azoospermic group were similar to those in the control group (see table). In the azoospermic group mean Johnsen’s score ⫾ SD was 5.1 ⫾ 1.1. Basal levels of growth hormone were similar in both groups. Serum growth hormone concentrations increased after growth hormone releasing hormone injections and the growth hormone levels peaked at 30 minutes in both groups. There was a significant difference in the 30-minute growth hormone response between the groups (see figure). There were no correlations between the peak value of growth hormone, and serum FSH, LH, prolactin, testosterone or estradiol levels in either group. There were also no correlations between Johnsen’s score and peak values of growth hormone in patients with azoospermia and a calculated Johnsen score.
2083
2084
GROWTH HORMONE RELEASING HORMONE AND INFERTILITY Characteristics of patient and control groups Mean ⫾ SD
Age FSH (mIU/ml.)* LH (mIU/ml.) Prolactin (ng./ml.) Testosterone (ng./ml.) Estradiol (pg./ml.) Johnsen’s score * p ⬍0.05.
Azoospermia Group
Control Group
33.1 ⫾ 4.1 10.0 ⫾ 8.5 6.0 ⫾ 3.2 9.6 ⫾ 4.3 5.4 ⫾ 1.6 25.2 ⫾ 6.4 5.1 ⫾ 1.1
29.8 ⫾ 3.8 4.1 ⫾ 2.5 3.6 ⫾ 1.5 7.2 ⫾ 4.0 4.7 ⫾ 0.7 25.7 ⫾ 13.6
clonidine (clonidine test).5 Ovesen et al evaluated growth hormone reserve among fertile men, patients with oligospermia and patients with asthenospermia using the intravenous arginine growth hormone stimulating test.4 They found that basal levels of growth hormone were similar among the 3 groups and that growth hormone secretion to arginine injection in patients with oligospermia or asthenospermia was significantly deficient compared to that of the control group. They suggested that reduced growth hormone secretion may represent only a relative deficiency since there was no difference in serum IGF-I levels among the 3 groups. Our results so supported these findings and suggest that relative growth hormone insufficiency may be a cause of impaired spermatogenesis. CONCLUSIONS
Results of growth hormone releasing hormone test in men with azoospermia and maturation arrest, and normal fertile men.
Growth hormone releasing hormone, the specific stimulatory neurohormone, directly stimulates growth hormone synthesis and release from somatotrophs in the pituitary gland. However, clonidine and arginine have indirect effects on growth hormone secretion through mechanisms involving stimulation of growth hormone releasing hormone secreting neurons and/or inhibition of hypothalamic IGF-1 release.14 Therefore, it is suggested that relative growth hormone insufficiency may be caused by reduced reactivity to growth hormone releasing hormone in pituitary growth hormone secretory cells as well as peripheral feedback inhibition of growth hormone secretion. We believe that relative growth hormone insufficiency may be caused by reduced reactivity to growth hormone releasing hormone in pituitary growth hormone secretory cells and is strongly involved in spermatogenic maturation arrest.
DISCUSSION
Growth hormone has an important role in the development and function of the reproductive system in men and exerts its effects on male gonads either directly or by local production of insulin-like growth factor I (IGF-I).1, 6, 7 Many studies have shown that growth hormone deficiency may result in reproductive dysfunction. The onset of puberty is delayed in patients with growth hormone deficiency and pubertal development can be accelerated by administration of growth hormone.2, 8 –10 It has been shown that the size of the penis and testis increased after therapy with recombinant growth hormone in patients with isolated growth hormone deficiency.2, 9 Furthermore, deprivation of growth hormone is known to cause delayed spermatogenesis which is characterized by the absence or near absence of spermatozoa in male rats.11 IGF-I receptors have been found in Sertoli and Leydig cells. In human testis Sertoli cells have been shown to produce or store IGF-I, which may be interpreted as expression of autocrine activity. It has been suggested that IGF-I may act on the process of differentiation of secondary spermatocytes and early spermatids that are intensely immunoreactive for IGF-I.7 When adding IGF-I isolated and cultured premature rat Leydig cells increased production of androgen in response to LH stimulation.12 In another study premature male rats treated with growth hormone and/or IGF-I had significantly higher responses of testosterone production to human chorionic gonadotropin loading.13 In our study stimulated growth hormone release was blunted in the azoospermic group; but basal levels of growth hormone did not differ between the 2 groups. The azoospermic group had increased serum FSH levels, which reflected the severely impaired damage of spermatogenesis. However, serum LH, prolactin, testosterone and estradiol levels were within the normal range and were not significantly different between the 2 groups. In the study by Shimonovitz et al 10 of 11 patients with azoospermia due to spermatogenetic maturation arrest had low growth hormone secretion during oral administration of
REFERENCES
1. Aynsley-Green, A., Zachmann, M. and Prader, A.: Interrelation of the therapeutic effects of growth hormone and testosterone on growth in hypopituitarism. J Pediatr, 89: 992, 1976 2. Tato, L., Zamboni, G., Antoniazzi, F. and Piubello, G.: Gonadal function and response to growth hormone (GH) in boys with isolated GH deficiency and to GH and gonadotropins in boys with multiple pituitary hormone deficiencies. Fertil Steril, 65: 830, 1996 3. Carani, C., Granata, A. R., De Rosa, M., Garau, C., Zarrilli, S., Paesano, L. et al: The effect of chronic treatment with GH on gonadal function in men with isolated GH deficiency. Eur J Endocrinol, 140: 224, 1999 4. Ovesen, P., Jorgensen, J. O., Kjaer, T., Ho, K. K., Orskov, H. and Christiansen, J. S.: Impaired growth hormone secretion and increased growth hormone-binding protein levels in subfertile males. Fertil Steril, 65: 165, 1996 5. Shimonovitz, S., Zacut, D., Ben Chetrit, A. and Ron, M.: Growth hormone status in patients with maturation arrest of spermatogenesis. Hum Reprod, 8: 919, 1993 6. Chatelain, P. G., Avallet, M. O., Nicolino, M., Lejeune, H., Clark, A., Chuzel, F. et al: Insulin-like growth factor I actions on steroidogenesis. Acta Paediatr, suppl., 339: 176, 1994 7. Vannelli, B. G., Barni, T., Orlando, C., Natali, A., Serio, M. and Balboni, G. C.: Insulin-like growth factor-I (IGF-I) and IGF-I receptor in human testis: an immunohistochemical study. Fertil Steril, 49: 666, 1988 8. Darendeliler, F., Hindmarsh, P. C., Preece, M. A., Cox, L. and Brook, C. G.: Growth hormone increases rate of pubertal maturation. Acta Endocrinol (Copenh), 122: 414, 1990 9. Laron, Z., Mimouni, F. and Pertzelan, A.: Effect of human growth hormone therapy on penile and testicular size in boys with isolated growth hormone deficiency: first year treatment. Isr J Med Sci, 19: 338, 1983 10. Tanner, J. M., Whitehouse, R. H., Hughes, P. C. and Carter, B. S.: Relative importance of growth hormone and sex steroids for the growth at puberty of trunk length, limb length, and muscle width in growth hormone-deficient children. J Pediatr, 89: 1000, 1976 11. Arsenijevic, Y., Wehrenberg, W. B., Conz, A., Eshkol, A., Sizonenko, P. C. and Aubert, M. L.: Growth hormone (GH) deprivation induced by passive immunization against rat GH-
GROWTH HORMONE RELEASING HORMONE AND INFERTILITY releasing factor delays sexual maturation in the male rat. Endocrinology, 124: 3050, 1989 12. Gelber, S. J., Hardy, M. P., Mendis-Handagama, S. M. and Casella, S. J.: Effects of insulin-like growth factor-I on androgen production by highly purified pubertal and adult rat Leydig cells. J Androl, 13: 125, 1992 13. Ohyama, K., Ohta, M., Nakagomi, Y., Yamori, T., Sano, T.,
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Shimura, Y. et al: Effects of growth hormone and insulin-like growth factor I on testosterone secretion in premature male rats. Endocr J, 42: 817, 1995 14. Aimaretti, G., Baffoni, C., DiVito, L., Bellone, S., Grottoli, S., Maccario, M. et al: Comparisons among old and new provocative tests of GH secretion in 178 normal adults. Eur J Endocrinol, 142: 347, 2000
Vol. 168, 2083–2085, November 2002 Printed in U.S.A.
DOI: 10.1097/01.ju.0000034265.27750.49
GROWTH HORMONE RELEASING HORMONE TEST FOR INFERTILE MEN WITH SPERMATOGENETIC MATURATION ARREST MASATO FUJISAWA, KUNITO YAMANAKA, HIROSHI OKADA, SOICHI ARAKAWA AND SADAO KAMIDONO From the Division of Urology, Department of Organs Therapeutics, Kobe University Graduate School of Medicine, Kobe, Japan
ABSTRACT
Purpose: Growth hormone has an important role in the function of the male reproductive system. We investigated infertile men with impaired growth hormone secretion. Materials and Methods: Growth hormone status was studied in 8 fertile men and 9 infertile men with azoospermia due to spermatogenetic maturation arrest. Growth hormone releasing hormone, the specific stimulatory neurohormone, was used in the growth hormone stimulation test. A dose of 100 g. of growth hormone releasing hormone was infused intravenously and serum growth hormone concentrations were measured at 0, 15, 30, 60, 90 and 120 minutes. Serum follicle-stimulating hormone, luteinizing hormone, prolactin, testosterone and estradiol were also measured before the test. Results: Serum follicle-stimulating hormone concentrations were significantly increased in the azoospermic group and basal levels of growth hormone were similar to those in the control group. Serum growth hormone concentrations increased after injection of growth hormone releasing hormone and the levels of growth hormone peaked after 30 minutes in both groups. At time 30 minutes growth hormone levels had decreased significantly more in the azoospermic group than in the controls. Men with azoospermia due to spermatogenetic maturation arrest had a low response to the growth hormone releasing hormone test. Conclusions: Relative growth hormone insufficiency, which may be caused by reduced reactivity to growth hormone releasing hormone in pituitary growth hormone secretory cells, is strongly related to spermatogenic dysfunction. KEY WORDS: somatotropin; somatotropin-releasing hormone; spermatogenesis; sperm maturation
Growth hormone has a role in pubertal development of male and female functions and somatic growth. It has been reported that patients with isolated growth hormone deficiency have a significantly delayed puberty and that the size of the testes and penis increased after growth hormone treatment.1, 2 Among men with isolated growth hormone deficiency due to neurosurgery, treatment with growth hormone increased levels of serum testosterone and volume of seminal plasma.3 Several studies have demonstrated by classical stimulating tests (arginine or clonidine) that growth hormone secretion is impaired in infertile men.4, 5 We evaluate growth hormone status in infertile men with spermatogenetic maturation arrest and used growth hormone releasing hormone as the specific stimulatory neurohormone.
and 120 minutes. Before the test serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin were assayed by chemiluminescence. Testosterone and estradiol concentrations were measured by radioimmunoassay. Serum was separated and stored at ⫺20C until it was assayed. Serum growth hormone concentrations were determined by immunoradiometric assay. Statistical evaluations were performed using the nonparametric Mann-Whitney U test to reveal differences between the control and azoospermic groups. Possible correlations were tested by Pearson’s correlation coefficients, with p ⬍0.05 considered significant.
RESULTS MATERIALS AND METHODS
This study included 9 men with a mean age ⫾ SD of 33.1 ⫾ 4.1 years (range 28 to 40) with nonobstructive azoospermia and testicular biopsy proven spermatogenetic maturation arrest, and 8 healthy fertile volunteers with a mean age ⫾ SD of 29.6 ⫾ 3.8 years (25 to 35) with normal seminograms who served as controls. None of the men with azoospermia had received any medication for male infertility before the study. All patients were subjected to the same study after informed consent was obtained. Each patient arrived at the hospital at 9:00 a.m. following an overnight fast and was placed in the supine position. A cannula was inserted into the antecubital vein and 100 g. per body of growth hormone releasing hormone was infused intravenously after a 30-minute rest period. Serum growth hormone concentrations were measured at 0, 15, 30, 60, 90 Accepted for publication May 24, 2002.
Serum FSH concentrations were significantly increased in the azoospermic group compared to those in the control group. Serum LH, prolactin, testosterone and estradiol concentrations in the azoospermic group were similar to those in the control group (see table). In the azoospermic group mean Johnsen’s score ⫾ SD was 5.1 ⫾ 1.1. Basal levels of growth hormone were similar in both groups. Serum growth hormone concentrations increased after growth hormone releasing hormone injections and the growth hormone levels peaked at 30 minutes in both groups. There was a significant difference in the 30-minute growth hormone response between the groups (see figure). There were no correlations between the peak value of growth hormone, and serum FSH, LH, prolactin, testosterone or estradiol levels in either group. There were also no correlations between Johnsen’s score and peak values of growth hormone in patients with azoospermia and a calculated Johnsen score.
2083
2084
GROWTH HORMONE RELEASING HORMONE AND INFERTILITY Characteristics of patient and control groups Mean ⫾ SD
Age FSH (mIU/ml.)* LH (mIU/ml.) Prolactin (ng./ml.) Testosterone (ng./ml.) Estradiol (pg./ml.) Johnsen’s score * p ⬍0.05.
Azoospermia Group
Control Group
33.1 ⫾ 4.1 10.0 ⫾ 8.5 6.0 ⫾ 3.2 9.6 ⫾ 4.3 5.4 ⫾ 1.6 25.2 ⫾ 6.4 5.1 ⫾ 1.1
29.8 ⫾ 3.8 4.1 ⫾ 2.5 3.6 ⫾ 1.5 7.2 ⫾ 4.0 4.7 ⫾ 0.7 25.7 ⫾ 13.6
clonidine (clonidine test).5 Ovesen et al evaluated growth hormone reserve among fertile men, patients with oligospermia and patients with asthenospermia using the intravenous arginine growth hormone stimulating test.4 They found that basal levels of growth hormone were similar among the 3 groups and that growth hormone secretion to arginine injection in patients with oligospermia or asthenospermia was significantly deficient compared to that of the control group. They suggested that reduced growth hormone secretion may represent only a relative deficiency since there was no difference in serum IGF-I levels among the 3 groups. Our results so supported these findings and suggest that relative growth hormone insufficiency may be a cause of impaired spermatogenesis. CONCLUSIONS
Results of growth hormone releasing hormone test in men with azoospermia and maturation arrest, and normal fertile men.
Growth hormone releasing hormone, the specific stimulatory neurohormone, directly stimulates growth hormone synthesis and release from somatotrophs in the pituitary gland. However, clonidine and arginine have indirect effects on growth hormone secretion through mechanisms involving stimulation of growth hormone releasing hormone secreting neurons and/or inhibition of hypothalamic IGF-1 release.14 Therefore, it is suggested that relative growth hormone insufficiency may be caused by reduced reactivity to growth hormone releasing hormone in pituitary growth hormone secretory cells as well as peripheral feedback inhibition of growth hormone secretion. We believe that relative growth hormone insufficiency may be caused by reduced reactivity to growth hormone releasing hormone in pituitary growth hormone secretory cells and is strongly involved in spermatogenic maturation arrest.
DISCUSSION
Growth hormone has an important role in the development and function of the reproductive system in men and exerts its effects on male gonads either directly or by local production of insulin-like growth factor I (IGF-I).1, 6, 7 Many studies have shown that growth hormone deficiency may result in reproductive dysfunction. The onset of puberty is delayed in patients with growth hormone deficiency and pubertal development can be accelerated by administration of growth hormone.2, 8 –10 It has been shown that the size of the penis and testis increased after therapy with recombinant growth hormone in patients with isolated growth hormone deficiency.2, 9 Furthermore, deprivation of growth hormone is known to cause delayed spermatogenesis which is characterized by the absence or near absence of spermatozoa in male rats.11 IGF-I receptors have been found in Sertoli and Leydig cells. In human testis Sertoli cells have been shown to produce or store IGF-I, which may be interpreted as expression of autocrine activity. It has been suggested that IGF-I may act on the process of differentiation of secondary spermatocytes and early spermatids that are intensely immunoreactive for IGF-I.7 When adding IGF-I isolated and cultured premature rat Leydig cells increased production of androgen in response to LH stimulation.12 In another study premature male rats treated with growth hormone and/or IGF-I had significantly higher responses of testosterone production to human chorionic gonadotropin loading.13 In our study stimulated growth hormone release was blunted in the azoospermic group; but basal levels of growth hormone did not differ between the 2 groups. The azoospermic group had increased serum FSH levels, which reflected the severely impaired damage of spermatogenesis. However, serum LH, prolactin, testosterone and estradiol levels were within the normal range and were not significantly different between the 2 groups. In the study by Shimonovitz et al 10 of 11 patients with azoospermia due to spermatogenetic maturation arrest had low growth hormone secretion during oral administration of
REFERENCES
1. Aynsley-Green, A., Zachmann, M. and Prader, A.: Interrelation of the therapeutic effects of growth hormone and testosterone on growth in hypopituitarism. J Pediatr, 89: 992, 1976 2. Tato, L., Zamboni, G., Antoniazzi, F. and Piubello, G.: Gonadal function and response to growth hormone (GH) in boys with isolated GH deficiency and to GH and gonadotropins in boys with multiple pituitary hormone deficiencies. Fertil Steril, 65: 830, 1996 3. Carani, C., Granata, A. R., De Rosa, M., Garau, C., Zarrilli, S., Paesano, L. et al: The effect of chronic treatment with GH on gonadal function in men with isolated GH deficiency. Eur J Endocrinol, 140: 224, 1999 4. Ovesen, P., Jorgensen, J. O., Kjaer, T., Ho, K. K., Orskov, H. and Christiansen, J. S.: Impaired growth hormone secretion and increased growth hormone-binding protein levels in subfertile males. Fertil Steril, 65: 165, 1996 5. Shimonovitz, S., Zacut, D., Ben Chetrit, A. and Ron, M.: Growth hormone status in patients with maturation arrest of spermatogenesis. Hum Reprod, 8: 919, 1993 6. Chatelain, P. G., Avallet, M. O., Nicolino, M., Lejeune, H., Clark, A., Chuzel, F. et al: Insulin-like growth factor I actions on steroidogenesis. Acta Paediatr, suppl., 339: 176, 1994 7. Vannelli, B. G., Barni, T., Orlando, C., Natali, A., Serio, M. and Balboni, G. C.: Insulin-like growth factor-I (IGF-I) and IGF-I receptor in human testis: an immunohistochemical study. Fertil Steril, 49: 666, 1988 8. Darendeliler, F., Hindmarsh, P. C., Preece, M. A., Cox, L. and Brook, C. G.: Growth hormone increases rate of pubertal maturation. Acta Endocrinol (Copenh), 122: 414, 1990 9. Laron, Z., Mimouni, F. and Pertzelan, A.: Effect of human growth hormone therapy on penile and testicular size in boys with isolated growth hormone deficiency: first year treatment. Isr J Med Sci, 19: 338, 1983 10. Tanner, J. M., Whitehouse, R. H., Hughes, P. C. and Carter, B. S.: Relative importance of growth hormone and sex steroids for the growth at puberty of trunk length, limb length, and muscle width in growth hormone-deficient children. J Pediatr, 89: 1000, 1976 11. Arsenijevic, Y., Wehrenberg, W. B., Conz, A., Eshkol, A., Sizonenko, P. C. and Aubert, M. L.: Growth hormone (GH) deprivation induced by passive immunization against rat GH-
GROWTH HORMONE RELEASING HORMONE AND INFERTILITY releasing factor delays sexual maturation in the male rat. Endocrinology, 124: 3050, 1989 12. Gelber, S. J., Hardy, M. P., Mendis-Handagama, S. M. and Casella, S. J.: Effects of insulin-like growth factor-I on androgen production by highly purified pubertal and adult rat Leydig cells. J Androl, 13: 125, 1992 13. Ohyama, K., Ohta, M., Nakagomi, Y., Yamori, T., Sano, T.,
2085
Shimura, Y. et al: Effects of growth hormone and insulin-like growth factor I on testosterone secretion in premature male rats. Endocr J, 42: 817, 1995 14. Aimaretti, G., Baffoni, C., DiVito, L., Bellone, S., Grottoli, S., Maccario, M. et al: Comparisons among old and new provocative tests of GH secretion in 178 normal adults. Eur J Endocrinol, 142: 347, 2000