1. Sullivan KA, Silverman A-J. 1993 The ontogeny of gonadotropin-releasing hormone neurons in the chick. Neuroendocrinology. 58:597-608.

2. Waldhauser F, Weissenbacher G, Frisch H, Pollak A. 1981 Pulsatile secretion of gonadotropins in early infancy. European Journal of Pediatrics. 137:71-74.

3. Apter D, Cacciatore B, Alfthan H, Stenman UH. 1989 Serum luteinizing hormone concentrations increase 100-fold in females from 7 years to adulthood, as measured by time-resolved immunofluorometric assay. J Clin Endocrinol Metab. 68:53-7.

4. Boyar RM, Rosenfeld RS, Kapen S, et al. 1974 Human puberty. Simultaneous augmented secretion of luteinizing hormone and testosterone during sleep. J Clin Invest. 54:609-18.

5. Wiemann JN, Clifton DK, Steiner RA. 1989 Pubertal changes in gonadotropin-releasing hormone and proopiomelanocortin gene expression in the brain of the male rat. Endocrinology. 124:1760-1767.

6. El Majdoubi M, Sahu A, Ramaswamy S, Plant TM. 2000 Neuropeptide Y: A hypothalamic brake restraining the onset of puberty in primates. Proc Natl Acad Sci U S A. 97:6179-84.

7. Spratt DI, O'Dea LSL, Schoenfeld D, Butler J, Rao PN, Crowley Jr WF. 1988 Neuroendocrine-gonadal axis in men: frequent sampling of LH, FSH, and testosterone. American Journal of Physiology. 254:E658-E666.

8. Hutson JM. 1985 A biphasic model for the hormonal control of testicular descent. Lancet. 2:419-21.

9. Berkowitz GS, Lapinski RH, Dolgin SE, Gazella JG, Bodian CA, Holzman IR. 1993 Prevalence and natural history of cryptorchidism. Pediatrics. 92:44-9.

10. Bardin CW, Ross GT, Rifkind AB, Cargille CM, Lipsett MB. 1969 Studies of the pituitary-Leydig cell axis in young men with hypogonadotropic hypogonadism and hyposmia: comparison with normal men, prepubertal boys, and hypopituitary patients. J Clin Invest. 48:2046-56.

11. Pitteloud N, Hayes FJ, Boeppk PA, DeCruz S, Seminere SB, McLaughlin DT, Crowley WF,Jr. The role of prior pubertal development, biochemical markers of testicular maturation, and genetics in deciding the phenotype heterogeneity of idiopathic hypogonadotrpic hypogonadism. J Clin Endocrinol Metab 2002: 87:152-160.

12. Boyar RM, Finkelstein JW, Witkin M, Kapen S, Weitzman E, Hellman L. 1973 Studies of endocrine function in "isolated" GnRH deficiency. Journal of Clinical Endocrinology and Metabolism. 36:64-72.

13. Lieblich JM, Rogol AD, White BJ, Rosen SW. 1982 Syndrome of anosmia with hypogonadotropic hypogonadism (Kallmann syndrome). American Journal of Medicine. 73:506-519.

14. Nachtigall LB, Boepple PA, Pralong FP, Crowley Jr WF. 1997 Adult-onset idiopathic hypogonadotropic hypogonadism-a treatable form of male infertility. New England Journal of Medicine. 336:410-415.

15. Santoro N, Filicori M, Crowley Jr WF. 1986 Hypogonadotropic disorders in men and women: diagnosis and therapy with pulsatile gonadotropin-releasing hormone. Endocrine Reviews. 7:11-23.

16. Spratt DI, Carr DB, Merriam GR, Scully RE, Rao PN, Crowley Jr WF. 1987 The spectrum of abnormal patterns of gonadotropin-releasing hormone secretion in men with idiopathic hypogonadotropic hypogonadism: clinical and laboratory correlations. Journal of Clinical Endocrinology and Metabolism. 64:283-291.

17. Whitcomb RW, Crowley Jr WF. 1990 Clinical review 4: diagnosis and treatment of isolated gonadotropin-releasing hormone deficiency in men. Journal of Clinical Endocrinology and Metabolism. 70:3-7.

18. Kallmann FJ, Schoenfeld WA. 1944 The genetic aspects of primary eunuchoidism. American Journal of Mental Deficiency. 158:203-236.

19. Schwankhaus JD, Currie J, Jaffe MJ, Rose SR, Sherins RJ. 1989 Neurologic findings in men with isolated hypogonadotropic hypogonadism. Neurology. 39:223-226.

20. Waldstreicher J, Seminara SB, Jameson JL, et al. 1996 The genetic and clinical heterogeneity of gonadotropin-releasing hormone deficiency in the human. Journal of Clinical Endocrinology and Metabolism. 81:4388-4395.

21. Filippi G. 1986 Klinefelter's syndrome in Sardinia. Clinical report of 265 hypogonadic males detected at the time of military check-up. Clinical Genetics. 30:276-284.

22. Fromantin M, Gineste J, Didier A, Rouvier J. 1973 Les impuberismes et les hypogonadismes a l'incorporation. 16:179-199.

23. McCullagh EP, Beck JC, Schaffenburg CA. 1953 A syndrome of eunuchoidism with spermatogenesis, normal urinary FSH and low or normal ICSH: "Fertile Eunuchs". Journal of Clinical Endocrinology and Metabolism. 13:489-509.

24. Boyar RM, Wu RH, Kapen S, Hellman L, Weitzman ED, Finkelstein JW. 1976 Clinical and laboratory heterogeneity in idiopathic hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 43:1268-75.

25. Pitteloud N, Boepple PA, DeCruz S, Valkenburgh SB, Crowley WF Jr, Hayes FJ. 2001 The fertile eunuch variant of idiopathic hypogonadotropic hypogonadism: spontaneous reversal associated with a homozygous mutation in the GnRH receptor. J Clin Endocrinol Metab.86: 2470-75.

26. Rogol AD, Mittal KK, White BJ, McGinniss MH, Lieblich JM, Rosen SW. 1980 HLA-compatible paternity in two "fertile eunuchs" with congenital hypogonadotropic hypogonadism and anosmia (the Kallmann syndrome). Journal of Clinical Endocrinology and Metabolism. 51:275-279.

27. Smals AGH, Kloppenborg PWC, van Haelst UJG, Lequin R, Benraad TJ. 1978 Fertile eunuch syndrome versus classic hypogonadotrophic hypogonadism. Acta Endocrinologica. 87:389-399.

28. Styne DM. 1991 Puberty and its disorders in boys. Endocrine and Metabolism Clinics of North America. 20:43-69.

29. Berga SL, Girton LG. 1989 The psychoneuroendocrinology of functional hypothalamic amenorrhea. Psychiatric Clinics of North America. 12:105-116.

30. Laughlin GA, Dominguez CE, Yen SSC. 1998 Nutritional and endocrine-metabolic aberrations in women with functional hypothalamic amenorrhea. Journal of Clinical Endocrinology and Metabolism. 83:25-32.

31. Warren MP. 1980 The effects of exercise on pubertal progression and reproductive function in girls. Journal of Clinical Endocrinology and Metabolism. 51:1150-1157.

32. Klibanski A, Beitins IZ, Badger T, Little R, McArthur JW. 1981 Reproductive function during fasting in men. Journal of Clinical Endocrinology and Metabolism. 53:258-263.

33. Veldhuis JD, Iranmanesh A, Evans WS, Lizarralde G, Thorner MO, Vance ML. 1993 Amplitude suppression of the pulsatile mode of immunoradiometric luteinizing hormone release in fasting-induced hypoandrogenemia in normal men. Journal of Clinical Endocrinology and Metabolism. 76:587-593.

34. McColl EM, Wheeler GD, Gomes P, Bhambhani Y, Cumming DC. 1989 The effects of acute exercise on pulsatile LH release in high-mileage male runners. Clin Endocrinol (Oxf). 31:617-21.

35. Wheeler GD, Wall SR, Belcastro AN, Cumming DC. 1984 Reduced serum testosterone and prolactin levels in male distance runners. Journal of the American Medical Association. 252:514-6.

36. Bagatell CJ, Dahl KD, Bremner WJ. 1994 The direct pituitary effect of testosterone to inhibit gonadotropin secretion in men is partially mediated by aromatization to estradiol. Journal of Andrology. 15:15-21.

37. Snegovskaya V, Viru A. 1993 Steroid and pituitary hormone responses to rowing: relative significance of exercise intensity and duration and performance level. Eur J Appl Physiol Occup Physiol. 67:59-65.

38. Alen M, Reinila M, Vihko R. 1985 Response of serum hormones to androgen administration in power athletes. Med Sci Sports Exerc. 17:354-9.

39. Ruokonen A, Alen M, Bolton N, Vihko R. 1985 Response of serum testosterone and its precursor steroids, SHBG and CBG to anabolic steroid and testosterone self-administration in man. J Steroid Biochem. 23:33-8.

40. MacAdams MR, White RH, Chipps BE. 1986 Reduction of serum testosterone levels during chronic glucocorticoid therapy. Ann Intern Med. 104:648-51.

41. Abs R, Verhelst J, Maeyaert J, et al. 2000 Endocrine consequences of long-term intrathecal administration of opioids. J Clin Endocrinol Metab. 85:2215-22.

42. Van den Berghe G, de Zegher F, Lauwers P, Veldhuis JD. 1994 Luteinizing hormone secretion and hypoandrogenaemia in critically ill men: effect of dopamine. Clin Endocrinol (Oxf). 41:563-9.

43. Wang C, Chan V, Yeung RT. 1978 Effect of surgical stress on pituitary-testicular function. Clin Endocrinol (Oxf). 9:255-66.

44. Wang C, Chan V, Tse TF, Yeung RT. 1978 Effect of acute myocardial infarction on pituitary-testicular function. Clin Endocrinol (Oxf). 9:249-53.

45. Lephart ED, Baxter CR, Parker CR, Jr. 1987 Effect of burn trauma on adrenal and testicular steroid hormone production. J Clin Endocrinol Metab. 64:842-8.

46. Van den Berghe G, de Zegher F, Bouillon R. 1998 Clinical review 95: Acute and prolonged critical illness as different neuroendocrine paradigms. J Clin Endocrinol Metab. 83:1827-34.

47. Spratt DI, Bigos ST, Beitins I, Cox P, Longcope C, Orav J. 1992 Both hyper- and hypogonadotropic hypogonadism occur transiently in acute illness: bio- and immunoactive gonadotropins. J Clin Endocrinol Metab. 75:1562-70.

48. Bates AS, Van't Hoff W, Jones PJ, Clayton RN. 1996 The effect of hypopituitarism on life expectancy. J Clin Endocrinol Metab. 81:1169-72.

49. Arafah BM. 1986 Reversible hypopituitarism in patients with large nonfunctioning pituitary adenomas. J Clin Endocrinol Metab. 62:1173-9.

50. Selmanoff M, Shu C, Petersen SL, Barraclough CA, Zoeller RT. 1991 Single cell levels of hypothalamic messenger ribonucleic acid encoding luteinizing hormone-releasing hormone in intact, castrated, and hyperprolactinemic male rats. Endocrinology. 128:459-66.

51. Carter JN, Tyson JE, Tolis G, Van Vliet S, Faiman C, Friesen HG. 1978 Prolactin-secreting tumors and hypogonadism in 22 men. N Engl J Med. 299:847-52.

52. Charbonnel B, Chupin M, Le Grand A, Guillon J. 1981 Pituitary function in idiopathic haemochromatosis: hormonal study in 36 male patients. Acta Endocrinol (Copenh). 98:178-83.

53. Thodou E, Asa SL, Kontogeorgos G, Kovacs K, Horvath E, Ezzat S. 1995 Clinical case seminar: lymphocytic hypophysitis: clinicopathological findings. J Clin Endocrinol Metab. 80:2302-11.

54. Snyder PJ, Fowble BF, Schatz NJ, Savino PJ, Gennarelli TA. 1986 Hypopituitarism following radiation therapy of pituitary adenomas. Am J Med. 81:457-62.

55. Littley MD, Shalet SM, Beardwell CG, Ahmed SR, Applegate G, Sutton ML. 1989 Hypopituitarism following external radiotherapy for pituitary tumours in adults. Q J Med. 70:145-60.

56. Eastman RC, Gorden P, Roth J. 1979 Conventional supervoltage irradiation is an effective treatment for acromegaly. J Clin Endocrinol Metab. 48:931-40.

57. Lam KS, Tse VK, Wang C, Yeung RT, Ho JH. 1991 Effects of cranial irradiation on hypothalamic-pituitary function--a 5-year longitudinal study in patients with nasopharyngeal carcinoma. Q J Med. 78:165-76.

58. Randeva HS, Schoebel J, Byrne J, Esiri M, Adams CB, Wass JA. 1999 Classical pituitary apoplexy: clinical features, management and outcome. Clin Endocrinol (Oxf). 51:181-8.

59. Arimura A, Kastin AJ, Gonzales-Barcena D, Siller J, Weaver RE, Schally AV. 1974 Disappearance of LH-releasing hormone in man as determined by radioimmunoassay. 3:421-425.

60. Pimstone B, Epstein S, Hamilton SM, LeRoith D, Hendricks S. 1977 Metabolic clearance and plasma half-disappearance time of exogenous gonadotropin-releasing hormone in normal subjects and in patients with liver disease and chronic renal failure. Journal of Clinical Endocrinology and Metabolism. 44:356-360.

61. Clarke IJ, Cummins JT. 1982 The temporal relationship between gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion in ovariectomized ewes. Endocrinology. 111:1737-1739.

62. Levine JN, Pau KYF, Ramirez VD, Jackson GL. 1982 Simultaneous measurement of luteinizing hormone releasing hormone and luteinizing hormone release in unanesthetized, ovariectomized sheep. Endocrinology. 111:1449-1455.

63. Whitcomb RW, O'Dea LSL, Finkelstein JS, Heavern DM, Crowley Jr WF. 1990 Utility of free alpha-subunit as an alternative neuroendocrine marker of gonadotropin-releasing hormone (GnRH) stimulation of the gonadotroph in the human: evidence from normal and GnRH-deficient men. Journal of Clinical Endocrinology and Metabolism. 70:1654-1661.

64. Hall JE, Whitcomb RW, Rivier JE, Vale WW, Crowley Jr WF. 1990 Differential regulation of luteinizing hormone, follicle-stimulating hormone, and free à-subunit from the gonadotrope by gonadotropin-releasing hormone (GnRH): Evidence from the use of two GnRH antagonists. Journal of Clinical Endocrinology and Metabolism. 70:328-335.

65. Hayes FJ, McNicholl DJ, Schoenfeld D, Marsh EE, Hall JE. 1999 Free alpha-subunit is superior to luteinizing hormone as a marker of gonadotropin-releasing hormone despite desensitization at fast pulse frequencies. Journal of Clinical Endocrinology and Metabolism. 1999:1028-1036.

66. Beitins IZ, Dufau ML, O'Loughlin K, Catt KJ, McArthur JW. 1977 Analysis of biological and immunological activities in the two pools of LH released during constant infusion of luteinizing hormone-releasing hormone (LHRH) in men. Journal of Clinical Endocrinology and Metabolism. 45:605-608.

67. de Roux N, Young J, Misrahi M, et al. 1997 A family with hypogonadotropic hypogonadism and mutations in the gonadotropin-releasing hormone receptor. New England Journal of Medicine. 337:1597-1602.

68. Franco B, Guioli S, Pragliola A, et al. 1991 A gene deleted in Kallmann's syndrome shares homology with neural cell adhesion and axonal path-finding molecules. Nature. 353:529-536.

69. Layman LC, Wilson JT, Huey LO, Lanclos LD, Plouffe Jr L, McDonough PG. 1992 Gonadotropin-releasing hormone, follicle-stimulating hormone beta, luteinizing hormone beta gene structure in idiopathic hypogonadotropic hypogonadism. Fertility and Sterility. 57:42-49.

70. Legouis R, Hardelin JP, Levilliers J, et al. 1991 The candidate gene for the X-linked Kallmann syndrome encodes a protein related to adhesion molecules. Cell. 67:423-435.

71. Jakacki RI, Kelch RP, Sauder SE, Lloyd JS, Hopwood NJ, Marshall JC. 1982 Pulsatile secretion of luteinizing hormone in children. Journal of Clinical Endocrinology and Metabolism. 55:453-458.

72. Rugarli EI, Lutz B, Kuratani SC, et al. 1993 Expression pattern of the Kallmann syndrome gene in the olfactory system suggests a role in neuronal targeting. Nature Genetics. 4:19-26.

73. Bick D, Franco B, Sherins RJ, et al. 1992 Brief report: intragenic deletion of the KALIG-1 gene in Kallmann's syndrome. New England Journal of Medicine. 326:1752-1755.

74. Edelman GM, Crossin KL. 1991 Cell adhesion molecules: implications for a molecular histology. 60:155-190.

75. Schwanzel-Fukuda M, Pfaff D. 1989 Origin of luteinizing hormone-releasing hormone neurons. Nature. 338:161-164.

76. Ballabio A, Bardoni B, Carrozzo R, et al. 1989 Continguous gene syndromes due to deletions in the distal short arm of the human X chromosome. Proceedings of the National Academy of Sciences of the United States of America. 86:10001-10005.

77. Clark SJ, Hauffa BP, Rodens KP, Styne DL, Kaplan SL, Grumbach MM. 1989 Hormone ontogeny in the ovine fetus: XIX: The effect of a potent luteinizing hormone-releasing factor agonist on gonadotropin and testosterone release in the fetus and neonate. Pediatric Research. 25:347-352.

78. Cohen-Salmon M, Tronche F, del Castillo I, Petit C. 1995 Characterization of the promoter of the human KAL gene, responsible for the X-chromosome-linked Kallmann syndrome. Gene. 164:235-242.

79. Hardelin JP, Levilliers J, Blanchard S, et al. 1993 Heterogeneity in the mutations responsible for X chromosome- linked Kallmann syndrome. Human Molecular Genetics. 2:373-377.

80. Georgopoulos NA, Pralong FP, Seidman CE, Seidman JG, Crowley Jr WF, Vallejo M. 1997 Genetic heterogeneity evidenced by low incidence of KAL-1 gene mutations in sporadic cases of gonadotropin-releasing hormone deficiency. Journal of Clinical Endocrinology and Metabolism. 82:213-217.

81. Parenti G, Rizzolo MG, Ghezzi M, et al. 1995 Variable penetrance of hypogonadism in a sibship with Kallmann syndrome due to a deletion of the KAL gene. American Journal of Medical Genetics. 57:476-478.

82. Quinton R, Duke VM, de Zoysa PA, et al. 1996 The neuroradiology of Kallmann's syndrome: A genotypic and phenotypic analysis. Journal of Clinical Endocrinology and Metabolism. 81:3010-3017.

83. Zanaria E, Muscatelli F, Bardoni B, et al. 1994 An unusual member of the nuclear hormone receptor superfamily responsible for X-linked adrenal hypoplasia congenita. Nature. 372:635-41.

84. Merke DP, Tajima T, Baron J, Cutler GB, Jr. 1999 Hypogonadotropic hypogonadism in a female caused by an X-linked recessive mutation in the DAX1 gene. N Engl J Med. 340:1248-52.

85. Habiby RL, Boepple P, Nachtigall L, Sluss PM, Crowley WF, Jr., Jameson JL. 1996 Adrenal hypoplasia congenita with hypogonadotropic hypogonadism: evidence that DAX-1 mutations lead to combined hypothalamic and pituitary defects in gonadotropin production [see comments]. J Clin Invest. 98:1055-62.

86. Caron P, Imbeaud S, Bennet A, Plantavid M, Camerino G, Rochiccioli P. 1999 Combined hypothalamic-pituitary-gonadal defect in a hypogonadic man with a novel mutation in the DAX-1 gene. J Clin Endocrinol Metab. 84:3563-9.

87. Seminara SB, Achermann JC, Genel M, Jameson JL, Crowley WF, Jr. 1999 X-linked adrenal hypoplasia congenita: a mutation in DAX1 expands the phenotypic spectrum in males and females. J Clin Endocrinol Metab. 84:4501-9.

88. Tabarin A, Achermann JC, Recan D, et al. 2000 A novel mutation in DAX1 causes delayed-onset adrenal insufficiency and incomplete hypogonadotropic hypogonadism. J Clin Invest. 105:321-8.

89. Nakayama Y, Wondisford FE, Lash RW, et al. 1990 Analysis of gonadotropin-releasing hormone gene structure in families with familial central precocious puberty and idiopathic hypogonadotropic hypogonadism. Journal of Clinical Endocrinology and Metabolism. 70:1233-1238.

90. Weiss J, Crowley Jr WF, Jameson JL. 1989 Normal structure of the gonadotropin-releasing hormone (GnRH) gene in patients with GnRH deficiency and idiopathic hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 69:299-303.

91. Mason AJ, Pitts SL, Nikolics K, et al. 1986 The hypogonadal mouse: reproductive functions restored by gene therapy. Science. 234:1372-1378.

92. de Roux N, Young J, Brailly-Tabard S, Misrahi M, Milgrom E, Schaison G. 1999 The same molecular defects of the gonadotropin-releasing hormone receptor determine a variable degree of hypogonadism in affected kindred. Journal of Clinical Endocrinology and Metabolism. 84:567-572.

93. Caron P, Chauvin S, Christin-Maitre S, et al. 1999 Resistance of hypogonadic patients with mutated GnRH receptor genes to pulsatile GnRH administration. Journal of Clinical Endocrinology and Metabolism. 84:990-996.

94. Layman LC, Peak DB, Xie J, Sohn SH, Reindollar RH, Gray MR. 1997 Mutation analysis of the gonadotropin-releasing hormone receptor gene in idiopathic hypogonadotropic hypogonadism. Fertility and Sterility. 68:1079-1085.

95. Pralong FP, Gomez F, Castillo E, et al. 1999 Complete hypogonadotropic hypogonadism associated with a novel inactivating mutation of the gonadotropin-releasing hormone receptor. Journal of Clinical Endocrinology and Metabolism. 84:3811-3816.

96. Seminara SB, Beranova M, Oliveira LMB, Martin KA, Crowley Jr WF, Hall JE. 2000 Successful use of pulsatile gonadotropin-releasing hormone (GnRH) for ovulation induction and pregnancy in a patient with GnRH receptor mutations. Journal of Clinical Endocrinology and Metabolism. 85:

97. Stojilkovic SS, Reinhart J, Catt KJ. 1994 Gonadotropin-releasing hormone receptors: structure and signal transduction pathways. Endocr Rev. 15:462-99.

98. Fan NC, Jeung E, Peng C, Olofsson JI, Krisinger J, Leung PCK. 1994 The human gonadotropin-releasing hormone (GnRH) receptor gene: cloning, genomic organization and chromosomal assignment. Molecular and Cellular Endocrinology. 103:R1-R6.

99. Layman LC, Cohen DP, Jin M, et al. 1998 Mutations in gonadotropin-releasing hormone receptor gene cause hypogonadotropic hypogonadism. Nature Genetics. 18:14-15.

100. Dode, C.; Levilliers, J.; Dupont, J.-M.; et al. 2003. Loss-of-function mutations in FGFR1 cause autosomal dominant Kallmann syndrome. Nature Genet. 33: 463-465.

101. de Roux, N.; Genin, E.; Carel, J.-C et al. 2003. Hypogonadotropic hypogonadism due to loss of function of the KiSS1-derived peptide receptor GPR54. Proc. Nat. Acad. Sci. 100: 10972-10976.

102. Seminara, S. B.; Messager, S.; Chatzidaki, E. E. et al. 2003. The GPR54 gene as a regulator of puberty. New Eng. J. Med. 349: 1614-1627.

103. Weiss J, Axelrod L, Whitcomb RW, Harris PE, Crowley Jr WF, Jameson JL. 1992 Hypogonadism caused by a single amino acid substitution in the beta subunit of luteinizing hormone. N Engl J Med. 326:179-183.

104. Lindstedt G, Nystrom E, Matthews C, Ernest I, Janson PO, Chatterjee K. 1998 Follitropin (FSH) deficiency in an infertile male due to FSH beta gene mutation. A syndrome of normal puberty and virilization but underdeveloped testicles with azoospermia, low FSH but high lutropin and normal serum testosterone concentrations. Clin Chem Lab Med. 36:663-5.

105. Phillip M, Arbelle JE, Segev Y, Parvari R. 1998 Male hypogonadism due to a mutation in the gene for the beta subunit of follicle stimulating hormone. New Engl J Med. 338:1729-1732.

106. Parks JS, Brown MR, Hurley DL, Phelps CJ, Wajnrajch MP. 1999 Heritable disorders of pituitary development. J Clin Endocrinol Metab. 84:4362-70.

107. Fluck C, Deladoey J, Rutishauser K, et al. 1998 Phenotypic variability in familial combined pituitary hormone deficiency caused by a PROP1 gene mutation resulting in the substitution of Arg-->Cys at codon 120 (R120C). J Clin Endocrinol Metab. 83:3727-34.

108. Deladoey J, Fluck C, Buyukgebiz A, et al. 1999 "Hot spot" in the PROP1 gene responsible for combined pituitary hormone deficiency. J Clin Endocrinol Metab. 84:1645-50.

109. Abs R, Van Vleymen E, Parizel PM, Van Acker K, Martin M, Martin JJ. 1990 Congenital cerebellar hypoplasia and hypogonadotropic hypogonadism. Journal of Neurological Sciences. 98:259-265.

110. Tapanainen JS, Aittomaki K, Min J, Vaskivuo T, Huhtaniemi IT. 1997 Men homozygous for an inactivating mutation of the follicle-stimulating hormone (FSH) receptor gene present variable suppression of spermatogenesis and fertility. Nature (London). 15:205-206.

111. Behre HM, Baus S, Kliesch S, Keck C, Simoni M, Nieschlag E. 1995 Potential of testosterone buciclate for male contraception: endocrine differences between responders and nonresponders. J Clin Endocrinol Metab. 80:2394-403.

112. O'Donnell L, Narula A, Balourdos G, et al. 2001 Impairment of spermatogonial development and spermiation after testosterone-induced gonadotropin suppression in adult monkeys (Macaca fascicularis). J Clin Endocrinol Metab. 86:1814-22.

113. Gromoll J, Simoni M, Nieschlag E. 1996 An activating mutation of the follicle-stimulating hormone receptor autonomously sustains spermatogenesis in a hypophysectomized man. J Clin Endocrinol Metab. 81:1367-70.

114. Burris AS, Rodbard HW, Winters SJ, Sherins RJ. 1988 Gonadotropin therapy in men with isolated hypogonadotropic hypogonadism: the response to human chorionic gonadotropin is predicted by initial testicular size. J Clin Endocrinol Metab. 66:1144-51.

115. Schaison G, Young J, Pholsena M, Nahoul K, Couzinet B. 1993 Failure of combined follicle-stimulating hormone-testosterone administration to initiate and/or maintain spermatogenesis in men with hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 77:1545-9.

116. Buchter D, Behre HM, Kliesch S, Nieschlag E. 1998 Pulsatile GnRH or human chorionic gonadotropin/human menopausal gonadotropin as effective treatment for men with hypogonadotropic hypogonadism: a review of 42 cases. Eur J Endocrinol. 139:298-303.

117. Recombinant Human FSH Product Development Group 1998 Recombinant follicle stimulating hormone: development of the first biotechnology product for the treatment of infertility.. Hum Reprod Update. 4:862-81.

118. Mannaerts B, Fauser B, Lahlou N, et al. 1996 Serum hormone concentrations during treatment with multiple rising doses of recombinant follicle stimulating hormone (Puregon) in men with hypogonadotropic hypogonadism. Fertil Steril. 65:406-10.

119. Finkel DM, Phillips JL, Snyder PJ. 1985 Stimulation of spermatogenesis by gonadotropins in men with hypogonadotropic hypogonadism. N Engl J Med. 313:651-5.

120. Vicari E, Mongioi A, Calogero AE, et al. 1992 Therapy with human chorionic gonadotrophin alone induces spermatogenesis in men with isolated hypogonadotrophic hypogonadism--long-term follow-up. Int J Androl. 15:320-9.

121. European Metrodin HP Study Group 1998 Efficacy and safety of highly purified urinary follicle-stimulating hormone with human chorionic gonadotropin for treating men with isolated hypogonadotropic hypogonadism. Fertil Steril. 70:256-62.

122. Barrio R, de Luis D, Alonso M, Lamas A, Moreno JC. 1999 Induction of puberty with human chorionic gonadotropin and follicle-stimulating hormone in adolescent males with hypogonadotropic hypogonadism. Fertil Steril. 71:244-8.

123. Liu PY, Turner L, Rushford D, et al. 1999 Efficacy and safety of recombinant human follicle stimulating hormone (Gonal-F) with urinary human chorionic gonadotrophin for induction of spermatogenesis and fertility in gonadotrophin-deficient men. Hum Reprod. 14:1540-5.

124. Liu L, Banks SM, Barnes KM, Sherins RJ. 1988 Two-year comparison of testicular responses to pulsatile gonadotropin-releasing hormone and exogenous gonadotropins from the inception of therapy in men with isolated hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 67:1140-5.

125. Kulin HE, Samojlik E, Santen R, Santner S. 1981 The effect of growth hormone on the Leydig cell response to chorionic gonadotrophin in boys with hypopituitarism. Clin Endocrinol (Oxf). 15:463-72.

126. Chatelain PG, Sanchez P, Saez JM. 1991 Growth hormone and insulin-like growth factor I treatment increase testicular luteinizing hormone receptors and steroidogenic responsiveness of growth hormone deficient dwarf mice. Endocrinology. 128:1857-62.

127. Spratt DI, Crowley Jr WF, Butler JP, Hoffman AR, Conn PM, Badger TM. 1985 Pituitary luteinizing hormone responses to intravenous and subcutaneous administration of gonadotropin releasing hormone in men. Journal of Clinical Endocrinology and Metabolism. 61:890-895.

128. Schopohl J, Mehltretter G, von Zumbusch R, Eversmann T, von Werder K. 1991 Comparison of gonadotropin-releasing hormone and gonadotropin therapy in male patients with idiopathic hypothalamic hypogonadism. Fertil Steril. 56:1143-50.

129. Devroey P. 1998 Clinical application of new micromanipulative technologies to treat the male. Hum Reprod. 13 Suppl 3:112-22; discussion 123-6.

130. Liebaers I, Bonduelle M, Van Assche E, Devroey P, Van Steirteghem A. 1995 Sex chromosome abnormalities after intracytoplasmic sperm injection. Lancet. 346:1095.