Chronic subcutaneous administration of kisspeptin-54 causes testicular degeneration in adult male rats.
Am J Physiol Endocrinol Metab
; 291(5): E1074-82, 2006 Nov.
Article
em En
| MEDLINE
| ID: mdl-16787965
ABSTRACT
The kisspeptins are KiSS-1 gene-derived peptides that signal through the G protein-coupled receptor-54 (GPR54) and have recently been shown to be critical regulators of reproduction. Acute intracerebroventricular or peripheral administration of kisspeptin stimulates the hypothalamic-pituitary-gonadal (HPG) axis. This effect is thought to be mediated via the hypothalamic gonadotropin-releasing hormone (GnRH) system. Chronic administration of GnRH agonists paradoxically suppresses the HPG axis after an initial agonistic stimulation. We investigated the effects of continuous peripheral kisspeptin administration in male rats by use of Alzet minipumps. Initially we compared the effects of acute subcutaneous administration of kisspeptin-10, -14, and -54 on the HPG axis. Kisspeptin-54 produced the greatest increase in plasma LH and total testosterone at 60 min postinjection and was used in the subsequent continuous administration experiments. Chronic subcutaneous long-term administration of 50 nmol kisspeptin-54/day for 13 days decreased testicular weight. Histological examination showed degeneration of the seminiferous tubules associated with a significant decrease in the circulating levels of the testes-derived hormone, inhibin B. Plasma free and total testosterone were also lower, although these changes did not reach statistical significance. Further studies examined the effects of shorter periods of continuous kisspeptin administration. Subcutaneous administration of 50 nmol kisspeptin-54 for 1 day increased plasma LH and testosterone. This effect was lost after 2 days of administration, suggesting a downregulation of the HPG axis response to kisspeptin following continuous administration. These findings indicate that kisspeptin may provide a novel tool for the manipulation of the HPG axis and spermatogenesis.
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Base de dados:
MEDLINE
Assunto principal:
Testículo
/
Proteínas Supressoras de Tumor
/
Endocrinologia
Tipo de estudo:
Etiology_studies
Limite:
Animals
Idioma:
En
Revista:
Am J Physiol Endocrinol Metab
Assunto da revista:
ENDOCRINOLOGIA
/
FISIOLOGIA
/
METABOLISMO
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Reino Unido