Gonadotropin-independent precocious puberty.
Gonadotropin-independent precocious puberty presents a challenge in diagnosis and management and in the elucidation of its pathophysiologic basis. Current therapeutic strategies reflect the fact that, irrespective of the underlying mechanism, the clinical and biochemical aspects of the disease process are consequences of gonadal autonomy. In MAS and in testotoxicosis, the most successful therapeutic maneuvers have focused on the local inhibition of steroidogenesis. Despite the positive reports on the use of MPA and cyproterone acetate, long-term experience with these preparations has been generally unsatisfactory, and there is a consensus that testolactone or ketoconazole represent optimal management. Although ketoconazole use, in our experience, has not been associated with any adverse effects either on liver function or on cortisol metabolism, the risk potential is always there. Nevertheless, its effects are dramatic in boys with testotoxicosis, and its mode of action allows for easy monitoring of its efficacy. Testolactone use in MAS, and in combination with spironolactone in testotoxicosis, appears to be relatively safe and reasonably effective. However, because serum testosterone levels are not lowered during treatment, assessment of efficacy depends largely on long-term evaluation of growth rate and of skeletal maturation. The etiology of these disorders remains unclear. The McCune-Albright syndrome is a multisystem disease and sporadic in nature. The organ involvement--ovary, thyroid, adrenal glands, bone, and kidney--is reminiscent of pseudohypoparathyroidism, ironically also bearing Albright's name (Albright's hereditary osteodystrophy, AHO). It is well established that in this syndrome, organ hypofunction associated with the AHO phenotype is caused by deficiency or dysfunction of the G-(or N) regulatory protein essential for production of intracellular cAMP and induction of specific protein kinases. The hypothesis that MAS is caused by abnormal regulation of the membrane receptor/kinase complex would seem logical. Despite its clinical similarity to MAS, the mechanism underlying testostoxicosis is clearly different. This disease is autosomal dominant and is expressed clinically only in boys. Its effects are confined to the production of gonadal autonomy. However, it is difficult to theorize how such autonomy could arise. The enzymatic reactions converting cholesterol to testosterone within the testis or adrenal gland are acquired typically through autosomal recessive inheritance, including the initial rate-limiting step of desmolase side-chain cleavage.(ABSTRACT TRUNCATED AT 400 WORDS)
Holland
F J
FJ
Faculty of Health Sciences, McMaster University Medical Center, Hamilton, Ontario, Canada.
D005260:Female; D005359:Fibrous Dysplasia, Polyostotic / Q000188:drug therapy / Q000503:physiopathology; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D006065:Gonadotropins, Pituitary / Q000502:physiology*; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D011547:Pseudohypoparathyroidism / Q000188:drug therapy / Q000503:physiopathology; D011629:Puberty, Precocious / Q000188:drug therapy / Q000235:genetics / Q000503:physiopathology
D006065:Gonadotropins, Pituitary; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone