Central administration of neuropeptide Y induces precocious puberty in female rats.
To examine the role of neuropeptide Y (NPY) in the regulation of puberty, the effects of various doses of NPY or saline injected into the 3rd ventricle of peripubertal female rats were determined. A single injection of NPY at a dose range of 10-20 micrograms into the 3rd ventricle of 30-day-old female rats advanced the time of vaginal opening (VO) and first ovulation by 4 days, as compared to saline-treated controls. Ova number and ovarian, adrenal and uterine weights at first estrous were similar in all animals regardless of treatment. The NPY-treated precocious animals showed lower body weight than did the VO-matched controls, but showed similar body weight as that of age-matched controls. Determination of plasma luteinizing hormone (LH) levels in the peripubertal female rats revealed that plasma LH was increased transiently immediately after NPY administration. Also, NPY-treated rats which had precocious puberty showed elevated pituitary and plasma LH levels on the day of VO. These results suggest that NPY can activate the hypothalamic-pituitary-gonadal axis to precociously initiate puberty.
Department of Veterinary and Comparative Anatomy, Washington State University, Pullman 99164-6520, USA.
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D000367:Age Factors; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D005260:Female; D007278:Injections, Spinal; D007986:Luteinizing Hormone / Q000187:drug effects / Q000378:metabolism; D009478:Neuropeptide Y / Q000494:pharmacology* / Q000502:physiology; D010053:Ovary / Q000187:drug effects; D010902:Pituitary Gland / Q000187:drug effects; D011629:Puberty, Precocious / Q000139:chemically induced*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D009478:Neuropeptide Y; D007986:Luteinizing Hormone