Open AccessThe Mammalian Target of Rapamycin as Novel Central Regulator of Puberty Onset via Modulation of Hypothalamic Kiss1 System
Author(s) -
Juan Roa,
David García-Galiano,
Luis Varela,
Miguel A. Sánchez-Garrido,
Rafael Pineda,
Juan Manuel Parreño Castellano,
Francisco Ruíz-Pino,
Marı́a T. Martı́n-Romero,
E. Aguilar,
Miguel López,
Francisco Gaytán,
Carlos Diéguez,
Leonor Pinilla,
Manuel TenaSempere
Publication year - 2009
Publication title -
endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.674
H-Index - 257
eISSN - 1945-7170
pISSN - 0013-7227
DOI - 10.1210/en.2009-0096
Subject(s) - endocrinology , medicine , pi3k/akt/mtor pathway , biology , leptin , hypothalamus , mechanistic target of rapamycin , arcuate nucleus , kisspeptin , signal transduction , microbiology and biotechnology , obesity
The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that operates as sensor of cellular energy status and effector for its coupling to cell growth and proliferation. At the hypothalamic arcuate nucleus, mTOR signaling has been recently proposed as transducer for leptin effects on energy homeostasis and food intake. However, whether central mTOR also participates in metabolic regulation of fertility remains unexplored. We provide herein evidence for the involvement of mTOR in the control of puberty onset and LH secretion, likely via modulation of hypothalamic expression of Kiss1. Acute activation of mTOR by l-leucine stimulated LH secretion in pubertal female rats, whereas chronic l-leucine infusion partially rescued the state of hypogonadotropism induced by food restriction. Conversely, blockade of central mTOR signaling by rapamycin caused inhibition of the gonadotropic axis at puberty, with significantly delayed vaginal opening, decreased LH and estradiol levels, and ovarian and uterine atrophy. Inactivation of mTOR also blunted the positive effects of leptin on puberty onset in food-restricted females. Yet the GnRH/LH system retained their ability to respond to ovariectomy and kisspeptin-10 after sustained blockade of mTOR, ruling out the possibility of unspecific disruption of GnRH function by rapamycin. Finally, mTOR inactivation evoked a significant decrease of Kiss1 expression at the hypothalamus, with dramatic suppression of Kiss1 mRNA levels at the arcuate nucleus. Altogether our results unveil the role of central mTOR signaling in the control of puberty onset and gonadotropin secretion, a phenomenon that involves the regulation of Kiss1 and may contribute to the functional coupling between energy balance and gonadal activation and function.