The development of Leydig cells and steroidogenesis are controlled by activation of luteinizing hormone (LH) receptors by placental HCG during intrauterine life and by pituitary LH after birth. Naturally occurring isolated LH deficiency in man thus provide useful information to understand the intriguing role of this gonadotrophin.
The patient was a 23 yr-old man from Afghanistan with a 46, XY karyotype. He presented with absent pubertal development and primary infertility. His parents have consanguinity and elder sister has primary infertility. He was 185 cm tall and thin (BMI 18 kg/m2) with arm span of 196 cm and lower segment 102 cm. There was no anosmia, midline defects or gynaecomastia. He had scanty pubic hair which came only after testosterone injection (Tanner stage 2) but no axillary hair. Penile length was normal and testicular volume about 8 ml on each side. He had normal erection and libido but scanty azoospermic ejaculation. LH was undetectable <0.1 by IRMA and RIA, FSH 18 IU/L (1–8), β-hCG <2 IU/L (0–5), testosterone 0.03 nmol/L (10–27), inhibin B 142 ng/L (<400), DHT 0.15 nmol/L (0.8–2.6), 8 am cortisol 540 nmol/L, ACTH 11 pmol/L. Acute LHRH stimulation failed to detect LH whereas FSH showed an exaggerated response, being stimulated from 18 to 54 IU/L. Testicular biopsy demonstrated immature Leydig and Sertoli cells, intact seminiferous tubules and rare spermatids. Testosterone IM was able to normalise FSH allowing azoospermic ejaculation. Subsequently, treatment with β-hCG restored testosterone secretion and semen analysis revealed mature spermatozoa.
This case represents a rare form of hypogonadotropic hypogonadism resulting from isolated LH deficiency. LH mediated high intra-testicular testosterone is essential for postnatal male sexual maturation and spermatogenesis.