New cells are added during both puberty and adulthood to hypothalamic regions that govern reproduction, homeostasis, and social behaviors, yet the functions of these late-born cells remain elusive. Here, we pharmacologically inhibited cell proliferation in ventricular zones during puberty or in adulthood and determined subsequent effects on the hormone-induced surge of luteinizing hormone (LH) ...

Ski protein is implicated in proliferation/differentiation in a variety of cells. We had previously reported that Ski protein is present in granulosa cells of atretic follicles, but not in preovulatory follicles, suggesting that Ski has a role in apoptosis of granulosa cells. The alternative fate of granulosa cells other than apoptosis is to differentiate to luteal cells; however, it is unknown...

GnRH is the key neuropeptide controlling reproductive function in all vertebrate species. Two different neuroendocrine mechanisms have evolved among female mammals to regulate the mediobasal hypothalamic (MBH) release of GnRH leading to the preovulatory secretion of LH by the anterior pituitary gland. In females of spontaneously ovulating species, including rats, mice, guinea pigs, sheep, monke...

The ability of luteinizing hormone-releasing hormone (LHRH) neurons to express the oncogene c-fos was examined during the estrous cycle in rats. The immunocytochemical localization of the c-fos-encoded antigen, Fos, was coupled with the immunocytochemical localization of LHRH. LHRH neurons showed no Fos immunoreactivity during diestrus-1, diestrus-2, estrus, or the morning of proestrus. However...

Gonadotrophin-releasing hormone (GnRH) neurones constitute the final output pathway of a neuronal network that controls the preovulatory luteinising hormone (LH) surge and ovulation. Throughout the reproductive cycle, several neurotransmitters stimulate and inhibit the activity of GnRH neurones, including oxytocin. The central administration of oxytocin antiserum abolishes the pro-oestrous LH s...

Hypokalemia produced different effects on steroid sex hormone concentrations in plasma and ovary in the mouse. Estradiol levels were slightly increased, whereas circulating progesterone was markedly decreased in all estrous periods. The preovulatory surge of gonadotropins and the secondary surge of follicle-stimulating hormone (FSH) at estrus were also decreased, but basal levels of both gonado...

In a normal menstrual cycle the hypothalamus in the brain signals the release of gonadotropin releasing hormone (GnRH) which, in turn stimulates the anterior pituitary gland to release FSH followed by LH. These hormones target the granulosa and theca cells respectively within the ovary. The dual action of these hormones causes the follicle to mature, and during its maturation oestrogen is incre...

Orexin A stimulates GnRH release from hypothalamic explants in vitro. The sites of action of orexin A in the regulation of LH release have been investigated in vivo in ovariectomized rats that were given vehicle or estradiol benzoate (EB), with or without an injection of progesterone 48 h later. Orexin A was administered intrahypothalamically under Saffan anesthesia, 50 h after the EB or vehicl...

The necessity of brain aromatization for sexual differentiation was investigated by treating pregnant guinea pigs with an aromatase inhibitor, 1,4,6-androstatriene-3,17-dione (ATD), from Day 30 to Day 55 of gestation. In postnatal Week 16, subjects were gonadectomized, and blood samples were collected after treatment with 10 micrograms estradiol benzoate (EB), used to elicit an LH surge; subjec...