Leptin-receptor gene transfer into the arcuate nucleus of female Fatty zucker rats using recombinant adeno-associated viral vectors stimulates the hypothalamo-pituitary-gonadal axis.
Fatty fa/fa Zucker rats with a missense mutation in the leptin receptor (OB-R) are obese and infertile with prolonged estrous cycles. To determine whether their reproductive deficits could be corrected by OB-R installation, we employed viral vectors to introduce the OB-R gene into either the arcuate nucleus (ARC) or the paraventricular nucleus (PVN) of the hypothalamus, sites of OB-R expression in wild-type rats. Recombinant adeno-associated viral (rAAV) vectors encoding the human leptin-receptor gene (rAAV-OB-Rb) were microinjected intraparenchymally to produce doxycycline-regulatable OB-R gene expression. Expression of the OB-R gene in the ARC and PVN was verified using reverse transcription-polymerase chain reaction. Expression of OB-R in the ARC, but not in the PVN, resulted in normalization of estrous cycle length, increased ovarian follicular development, and decreased serum progesterone levels. Compared to saline-injected rats, hypothalamic expression of neuropeptide Y (NPY) and pro-opiomelanocortin were decreased in ARC rAAV-OB-Rb-injected rats. Parallel decreases were noted in NPY and beta-endorphin (beta-END) concentrations in the hypothalamus, whereas luteinizing hormone-releasing hormone (LHRH) levels increased. These studies showed that rAAV vectors can be successfully used to install functional OB-R in the hypothalamus for extended periods. The resultant stimulation of the hypothalamo-pituitary-gonadal (HPG) axis in ARC-injected rats was probably brought about by the observed decreases in NPY and beta-END, which inhibit hypothalamic LHRH. Because these changes were seen in ARC-injected, but not in PVN-injected, rats, the results suggest that the ARC may be the primary site where leptin acts to regulate the HPG axis.
Keen-Rhinehart
Erin
E
Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL 32601, USA.
Kalra
Satya P
SP
Kalra
Pushpa S
PS
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D000229:Dependovirus / Q000235:genetics; D030762:Estrous Cycle; D005260:Female; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006728:Hormones / Q000378:metabolism; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D007031:Hypothalamus / Q000378:metabolism; D008845:Microinjections; D009479:Neuropeptides / Q000378:metabolism; D009765:Obesity / Q000503:physiopathology*; D006080:Ovarian Follicle / Q000503:physiopathology; D010053:Ovary / Q000503:physiopathology*; D011374:Progesterone / Q000097:blood; D051381:Rats; D011924:Rats, Zucker / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D054411:Receptors, Leptin; D011995:Recombination, Genetic
D006728:Hormones; C515448:LEPR protein, human; D009479:Neuropeptides; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; D011374:Progesterone