CHEMICAL ENDOCRINOLOGY

By N. ALENO

CONTENTS NEUROENDOCRINE CONTROL OF TESTICULAR FUNCTION LEYDIG CELL FUNCTION IN MAN SPERMATOGENESIS AND ITS REGULATION IN HIGHER PRIMATES NORMAL AND DELAYED PUBERTY CONGENITAL HYPOGONADOTROPIC HYPOGONADISM: CLINICAL FEATURES AND PATHOPHYSIOLOGY MALE HYPOGONADISM RESULTING FROM MUTATIONS IN THE GENES FOR THE GONADOTROPIN SUBUNITS AND THEIR RECEPTORS HYPOGONADISM IN MALES WITH CONGENITAL ADRENAL HYPERPLASIA MALE HYPOGONADISM RESULTING FROM DISORDERS OF THE PITUITARY AND SUPRASELLAR REGION KLINEFELTER’S SYNDROME CRYPTORCHIDISM HYPOGONADISM IN MEN WITH HIV-AIDS HYPOGONADISM IN MEN WITH CHRONIC RENAL FAILURE MALE HYPOGONADISM RESULTING FROM CANCER AND CANCER TREATMENTS AN ENSEMBLE PERSPECTIVE OF AGING-RELATED HYPOANDROGENEMIA IN MEN ENVIRONMENTAL CAUSES OF TESTICULAR DYSFUNCTION EXERCISE AND MALE HYPOGONADISM: TESTOSTERONE, THE HYPOTHALAMIC– PITUITARY–TESTICULAR AXIS, AND PHYSICAL EXERCISE TESTOSTERONE, SHBG, AND THE METABOLIC CARDIOVASCULAR SYNDROME ANDROGEN REPLACEMENT THERAPY IN HYPOGONADAL MEN STIMULATION OF SPERMATOGENESIS IN HYPOGONADOTROPIC MEN OVERVIEW THE PROXIMATE REGULATOR OF TESTICULAR FUNCTION IS GONADOTROPIN-RELEASING HORMONE (GNRH), WHICH IS PRODUCED IN NEURONS SCATTERED THROUGHOUT THE ANTERIOR HYPOTHALAMUS WHEN IT REACHES THE ANTERIOR PITUITARY, GNRH STIMULATES THE SYNTHESIS AND SECRETION OF THE PITUITARY GONADOTROPIC HORMONES, LUTEINIZING HORMONE (LH), AND FOLLICLE-STIMULAT- ING HORMONE (FSH) LH AND FSH ARE RELEASED INTO THE CIRCULATION IN BURSTS AND ACTIVATE G PROTEIN-COUPLED RECEPTORS (GPCRS) ON LEYDIG AND SERTOLI CELLS, RESPECTIVELY, THAT STIMULATE TESTOSTERONE PRODUCTION AND SPERMATOGENESIS THE SYSTEM IS TIGHTLY REGULATED AND IS MAINTAINED AT A PROPER SET POINT BY THE NEGATIVE FEEDBACK EFFECTS OF TESTICULAR STEROIDS AND INHIBIN-B TESTICULAR FUNCTION IS ALSO IN?UENCED BY MULTIPLE INTERNAL AND EXTERNAL ENVIRONMENTAL FACTORS NEUROENDOCRINE CONTROL OF TESTICULAR FUNCTION OVERVIEW GNRH SYNTHESIS AND SECRETION GONADOTROPHS AND GNRH RECEPTORS THE GONADOTROPIC HORMONES PULSATILE GONADOTROPIN SECRETION LH CONTROL OF TESTOSTERONE SYNTHESIS ESTROGENS IN MALES TESTICULAR CONTROL OF GONADOTROPIN SECRETION INHIBIN, ACTIVIN, AND FSH NEUROENDOCRINE MECHANISMS FOR THE DIFFERENTIAL CONTROL OF FSH AND LH CONCLUSION REFERENCES