Interaction between suprachiasmatic nucleus (SCN) and leptin hormone and their effect on puberty

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In the first study, hamsters were SCN lesioned, exposed to different feeding regimes, adrenalectomized and implanted with cortisol implants and leptin levels were examined. The results showed that the diurnal rhythm of leptin hormone release is directly regulated by the SCN. In the second study, animals were SCN lesioned, pinealectomized and melatonin infused. Infusions suppressed the leptin levels independently from the duration of the infusion (p<0,05). In the third study, five experiments were performed. In the first four experiment, animals were injected, subcutaneously infused, and intracerebroventrically infused with leptin at CT 10. Leptin hormone phase advanced the locomotor activity (p<0,05). In the fifth experiment, hamsters

were SCN lesioned and received timed leptin infusions. Infusions restored the arrhythmic locomotor activity of the SCN lesioned animals. In the fourth study, two experiments were performed. In the first, female hamsters were paired and injected with leptin, insulin, melatonin and saline. After weaning, the prepubertal hamsters were examined for their body, testes, adipose, epididymis and seminal vesicle weights. All parameters were heavier in hamsters borned to leptin injected mothers (p<0,01). In the second experiment, pregnant hamsters were injected with leptin. After parturition, the newborn pups were decapitated and their brains were examined for their weight, volume and the number of the neurons. Leptin accelerated the development of the brains. In the fifth study, photoperiodic control of leptin rhythm was investigated in hamsters with intact or pinealectomized groups. The leptin levels were the lowest in lipectomy group at the first week however leptin levels were similar to each other in lipectomy and leptin injected groups at the eighth week of the experiment.