to a pituitary production of both LH and FSH. While this is typical in menopause, it is abnormal in the reproductive years. There it may be a sign of: Premature menopause Gonadal dysgenesis, Turner syndrome, Klinefelter syndrome Castration Swyer syndrome Polycystic ovary syndrome Certain forms of congenital adrenal hyperplasia Testicular failure Pregnancy - BetaHCG can mimic LH so tests may show elevated LH Note: A medical drug for inhibiting luteinizing hormone secretion is Butinazocine. Deficiency Diminished secretion of LH can result in failure of gonadal function (hypogonadism). This condition is typically manifest in males as failure in production of normal numbers of sperm. In females, amenorrhea is commonly observed. Conditions with very low LH secretions include: Pasqualini syndrome Kallmann syndrome Hypothalamic suppression Hypopituitarism Eating disorder Female athlete triad Hyperprolactinemia Hypogonadism Gonadal suppression therapy GnRH antagonist GnRH agonist (inducing an initial stimulation (flare up) followed by permanent blockage of the GnRH pituitary receptor) As a medication LH is available mixed with FSH in the form of menotropin, and other forms of urinary gonadotropins. More purified forms of urinary gonadotropins may reduce the LH portion in relation to FSH. Recombinant LH is available as lutropin alfa (Luveris). All these medications have to be given parenterally. They are commonly used in infertility therapy to stimulate follicular development, the notable one being in IVF therapy. Often, HCG medication is used as an LH substitute because it activates the same receptor. Medically used hCG is derived from urine of pregnant women, is less costly, and has a longer half-life than LH. Role in phosphorylation Phosphorylation is a biochemical process that involves the addition of phosphate to an organic compound. Steroidogenesis entails processes by which cholesterol is converted to biologically active steroid hormones. Recent study shows that LH via a PKA signaling pathway regulates the phosphorylation and localization of DRP1 within mitochondria of the steroidogenic cells of the ovary. References External links Recombinant proteins Glycoproteins Gonadotropin-releasing hormone and gonadotropins Merck brands Peptide hormones Sex hormones Human hormones Hormones of the hypothalamus-pituitary-gonad axis Anterior pituitary hormones