Male-female differences in 6-sulfatoxymelatonin excretion in hypopituitary patients

ABSTRACT Objective To evaluate melatonin secretion in adult hypopituitary patients with Growth Hormone deficiency (AGHD) on and off replacement therapy. Subjects and methods We studied 48 subjects: 12 (6 males) untreated AGHD (AGHDnt), 20 (10 males) treated AGHD (AGHDt) and 16 healthy subjects (8 males) as control group (CG). We measured urinary 6-sulfatoxymelatonin (6-SM) in total (24 h samples), nocturnal (6-SMn): 1800-0800 and diurnal samples (6-SMd): 0800-1800. Results Significant differences were observed among the 3 groups of male subjects, in total 6-SM (p < 0.05), nocturnal 6-SM (p < 0.02) and nighttime-daytime delta values (p < 0.003). CG had significantly higher values than the AGHDnt in total 6-SM (p < 0.01), nocturnal 6-SM (p < 0.05) and nighttime-daytime delta values (p < 0.01). AGHDt patients showed significantly higher levels in nighttime-daytime delta values than AGHDnt patients (p < 0.05). In females, no significant differences were found among the 3 groups studied in total, nocturnal, diurnal or nighttime-daytime delta values. In males, significant correlations were found among total 6-SM (r = 0.58; p = 0.029), nocturnal 6-SM (r = 0.70; p = 0.006) and nighttime-daytime delta values (r = 0.71; p = 0.004) vs. serum IGF-1 levels in subjects evaluated. In females, significant correlations were found among total 6-SM (r = 0.57; p = 0.02) vs. serum IGF-1 levels in subjects evaluated. A tendency towards a significant correlation was found in diurnal 6-SM (r = 0.48; p = 0.07). Conclusions Our findings show a sexual dimorphism in 6-SM excretion in AGHD patients and provide an interesting approach to a further understanding of some chronobiological disorders involved in GH deficiency

Growth hormone during the transtion period

La etapa de transición ha sido definida como el período de la vida que comienza hacia el fin de la pubertad y finaliza cuando se adquiere la maduración adulta completa. Esta fase dura aproximadamente 6 a 8 años y durante la misma se producen una serie de modificaciones cuantitativas y cualitativas en la esfera física y psíquica, caracterizadas por la adquisición de la talla y composición corporal adulta, del pico de masa ósea, la obtención de una plena capacidad fértil y, finalmente, de las características psicosociales propias del adulto. Deben recordarse los efectos que la hormona de crecimiento (GH) ejerce a lo largo de toda la vida del sujeto sobre el metabolismo, función y estructura cardíaca, hueso, composición corporal y calidad de vida. Sin embargo, hay datos conflictivos sobre la necesidad de continuar, sin interrupción, con la terapia de GH durante la etapa de transición. Se debe tener en cuenta, también, que existe un grupo de pacientes que adquieren la insuficiencia de GH durante el período de transición. Si bien existen claras evidencias que indican no discontinuar el tratamiento luego de haber finalizado la etapa de crecimiento, los pacientes deben ser reevaluados previamente para constatar si el déficit es suficientemente severo como para justificar mantener la terapéutica con GH. La respuesta a gran parte de estas dudas podrá resolverse con estudios randomizados y observacionales a largo plazo, desarrollados por equipos multidisciplinarios especializados.148-156hugofideleff@arnet.com.arCuatrimestralTransition phase has been defined as the period of life starting in late puberty and ending with full adult maturation. This phase extends over approximately 6 to 8 years. A number of quantitative and qualitative changes occur during this phase both in physical and psychic aspects, which are characterized by attainment of adult height and body composition, peak bone mass, full reproductive potential and, finally, psychosocial characteristics inherent to adults. We should remember the effects exerted by growth hormone (GH) throughout the life of a subject on metabolism, cardiac function and structure, bone, body composition and quality of life. However, there are controversial data on the need to continue GH therapy during the transition period with no discontinuation. We should also take into account that there is a group of patients who develop GH deficiency during the transition period. Even if there is clear evidence against discontinuation of therapy after completion of the growth period, patients should be previously reevaluated to confirm if GH deficiency is severe enough to warrant continuation of GH therapy. The response to many of these issues may be obtained from long-term randomized and observational studies conducted by specialized multidisciplinary teams