title: Programming of GnRH feedback controls timing puberty and adult reproductive activity.
abstract: The timing of puberty generally differs between sexes, and this may be due to sex differences in the organization of steroid feedback systems. We propose that the reproductive neuroendocrine default sex is female. If the individual is male, the feedback control of GnRH secretion is programmed early in development, and the pubertal GnRH rise is either advanced or delayed depending upon species. This developmental programming is by androgens. Early programming also reorganizes adult reproductive neuroendocrine function to change a pattern of cyclic gamete release (periodic ovulations) requiring multiple feedback systems to that of a continuous one (spermatogenesis) requiring only the negative feedback control. The multiple feedback systems underlying the complex ovulatory cycle are innate, and in the male the unnecessary feedbacks are abolished or rendered less sensitive during development by the estrogenic, as well as the androgenic metabolites of testosterone.
authors.affiliation: Reproductive Sciences Program, Departments of Obstetrics & Gynecology, Pediatrics, and Physiology, University of Michigan, Ann Arbor, MI 48109-0404, United States. dfoster@umich.edu
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Foster
authors.forename: Leslie M
authors.initials: LM
authors.lastname: Jackson
authors.forename: Vasantha
authors.initials: V
authors.lastname: Padmanabhan
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D008297:Male; D008954:Models, Biological; D009421:Nervous System Malformations / Q000150:complications; D009474:Neurons / Q000378:metabolism; D011627:Puberty / Q000502:physiology*; D011673:Pulsatile Flow / Q000502:physiology; D012098:Reproduction / Q000502:physiology*; D012727:Sex Characteristics; D046468:Sexual Development; D012756:Sheep; D013995:Time
chemical_list: D012739:Gonadal Steroid Hormones; D007987:Gonadotropin-Releasing Hormone