Leptin-responsive GABAergic neurons regulate fertility through pathways that result in reduced kisspeptinergic tone.
The adipocyte-derived hormone leptin plays a critical role in the central transmission of energy balance to modulate reproductive function. However, the neurocircuitry underlying this interaction remains elusive, in part due to incomplete knowledge of first-order leptin-responsive neurons. To address this gap, we explored the contribution of predominantly inhibitory (GABAergic) neurons versus excitatory (glutamatergic) neurons in the female mouse by selective ablation of the leptin receptor in each neuronal population: Vgat-Cre;Lepr(lox/lox) and Vglut2-Cre;Lepr(lox/lox) mice, respectively. Female Vgat-Cre;Lepr(lox/lox) but not Vglut2-Cre;Lepr(lox/lox) mice were obese. Vgat-Cre;Lepr(lox/lox) mice had delayed or absent vaginal opening, persistent diestrus, and atrophic reproductive tracts with absent corpora lutea. In contrast, Vglut2-Cre;Lepr(lox/lox) females exhibited reproductive maturation and function comparable to Lepr(lox/lox) control mice. Intracerebroventricular administration of kisspeptin-10 to Vgat-Cre;Lepr(lox/lox) female mice elicited robust gonadotropin responses, suggesting normal gonadotropin-releasing hormone neuronal and gonadotrope function. However, adult ovariectomized Vgat-Cre;Lepr(lox/lox) mice displayed significantly reduced levels of Kiss1 (but not Tac2) mRNA in the arcuate nucleus, and a reduced compensatory luteinizing hormone increase compared with control animals. Estradiol replacement after ovariectomy inhibited gonadotropin release to a similar extent in both groups. These animals also exhibited a compromised positive feedback response to sex steroids, as shown by significantly lower Kiss1 mRNA levels in the AVPV, compared with Lepr(lox/lox) mice. We conclude that leptin-responsive GABAergic neurons, but not glutamatergic neurons, act as metabolic sensors to regulate fertility, at least in part through modulatory effects on kisspeptin neurons.
Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, and Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115.
Cecilia
C
Martin
Víctor M
VM
Navarro
Serap
S
Simavli
Linh
L
Vong
Rona S
RS
Carroll
Bradford B
BB
Lowell
Ursula B
UB
Kaiser
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D005298:Fertility / Q000187:drug effects / Q000502:physiology*; D059330:GABAergic Neurons / Q000187:drug effects / Q000378:metabolism*; D059648:Kisspeptins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D020738:Leptin / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D051379:Mice; D018345:Mice, Knockout; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
C106628:KISS1 protein, human; D059648:Kisspeptins; D020738:Leptin; D054411:Receptors, Leptin; D004958:Estradiol; D007986:Luteinizing Hormone
GABA; female; glutamate; leptin; metabolism; reproduction