<unk>  is secreted in the hypophysial portal bloodstream at the median eminence. The portal blood carries the<unk>  to the pituitary gland, which contains the gonadotrope cells, where<unk>  activates its own receptor,<unk>  receptor <unk> R), a seven-transmembrane G-protein-coupled receptor that stimulates the beta isoform of Phosphoinositide phospholipase C, which goes on to mobilize calcium and protein kinase C. This results in the activation of proteins involved in the synthesis and secretion of the gonadotropins LH and FSH.<unk>  is degraded by proteolysis within a few minutes.<unk>  activity is very low during childhood, and is activated at puberty or adolescence. During the reproductive years, pulse activity is critical for successful reproductive function as controlled by feedback loops. However, once a pregnancy is established,<unk>  activity is not required. Pulsatile activity can be disrupted by hypothalamic-pituitary disease, either dysfunction (i.e., hypothalamic suppression) or organic lesions (trauma, tumor). Elevated prolactin levels decrease<unk>  activity. In contrast, hyperinsulinemia increases pulse activity leading to disorderly LH and FSH activity, as seen in polycystic ovary syndrome (PCOS).<unk>  formation is congenitally absent in Kallmann syndrome. Control of FSH and LH At the pituitary,<unk>  stimulates the synthesis and secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These processes are controlled by the size and frequency of<unk>  pulses, as well as by feedback from androgens and estrogens. Low-frequency<unk>  pulses are required for FSH release, whereas high-frequency<unk>  pulses stimulate LH pulses in a one-to-one manner. There are differences in<unk>  secretion between females and males. In males,<unk>  is secreted in pulses at a constant frequency; however, in females, the frequency of the pulses varies during the menstrual cycle, and there is a large surge of<unk>  just before ovulation.<unk>  secretion is pulsatile in all vertebrates, and is necessary for correct reproductive function. Thus, a single hormone,<unk> 1, controls a complex process of follicular growth, ovulation, and corpus luteum maintenance in the female, and spermatogenesis in the male. Neurohormone<unk>  is considered a neurohormone, a hormone produced in a specific neural cell and released at its neural terminal. A key area for production of<unk>  is the preoptic area of the hypothalamus, which contains most of the<unk> -secreting neurons.<unk>  neurons originate in the nose and migrate into the brain, where they are scattered throughout the medial septum and hypothalamus and connected by very long >1-millimeter-long dendrites. These bundle together so they receive shared synaptic input, a process that allows them to synchronize their<unk>  release. The<unk>  neurons are regulated by many different afferent neurons, using several different transmitters (including norepinephrine, GABA, glutamate). For instance, dopamine appears to stimulate LH release (through<unk>  in estrogen-progesterone-primed females; dopamine may inhibit LH release in ovariectomized females. Kisspeptin appears to be an important regulator of<unk>  release.<unk>  release can also be regulated by estrogen. It has been reported that there are kisspeptin-producing neurons that also express estrogen receptor alpha. Other organs<unk>  is found in organs outside of the hypothalamus and pituitary, and its role in other life processes is poorly understood. For instance, there is likely to be a role for<unk> 1 in the placenta and in the gonads.<unk>  and<unk>  receptors are also found in cancers of the breast, ovary, prostate, and endometrium.
Gonadotropin-releasing hormone
Menotropin
Counterregulatory hormone
Antigonadotropin
Prolactin-releasing peptide
Luteinizing hormone
Growth hormone–releasing hormone
Progonadotropin