Chronic neuropeptide Y infusion during lactation suppresses pup growth and reduces the length of lactational infertility in rats.
In lactating rats, food restriction potentiates the already high levels of hypothalamic neuropeptide Y (NPY). To investigate the role that high levels of NPY might play in the prolongation of lactational infertility that typically accompanies a food restricted lactation we investigated the effects of chronic central infusions of NPY in ad libitum-fed lactating females. First, we compared the effects of intracerebroventricular (icv) infusion of NPY from Days 12-19 postpartum at a dose of 14.4 microg/day with a similar treatment in nonlactating females. In subsequent experiments we examined the effects of NPY infusions into the lateral ventricle at doses of 6 or 20 mug/day or unilaterally into the medial preoptic area at a dose of 1 microg/day from either Days 12-19 or 7-21 postpartum. Effects on food intake; female body weight; and, where appropriate, litter weight and length of lactational diestrus were compared between NPY and vehicle-treated females. As expected NPY infusion produced a robust increase in body weight and food intake in nonlactating females that was accompanied by a suppression of cyclicity. By contrast NPY treatment in lactating rats resulted in a marked decrease in litter growth and an earlier termination of lactational diestrus.
Woodside
Barbara
B
Psychology Department, Center for Studies in Behavioral Neurobiology, Concordia University, 7141 Sherbrooke St. W., Montréal, Québéc, H4B 1R6, Canada. woodside@csbn.concordia.ca
Beaulé
Christian
C
Lauay
Christine
C
D000818:Animals; D000833:Animals, Suckling / Q000254:growth & development*; D004435:Eating / Q000187:drug effects; D005260:Female; D007247:Infertility, Female / Q000503:physiopathology*; D007276:Injections, Intraventricular; D007774:Lactation / Q000187:drug effects*; D009478:Neuropeptide Y / Q000494:pharmacology*; D011301:Preoptic Area / Q000187:drug effects; D011388:Prolactin / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015430:Weight Gain / Q000187:drug effects
D009478:Neuropeptide Y; D011388:Prolactin