[Biology Class Notes] on Luteinizing Hormone Pdf for EXAM

Hormones extensively regulate the reproductive system of the human body and one such hormone is luteinizing hormone. That important hormone is vital to ensuring a healthy reproductive system, with different roles in men and women’s bodies. Having your reproductive health under control requires understanding that important hormone.

Luteinizing hormone (LH) is produced in the anterior pituitary gland, and released. This hormone is called a gonadotrophic hormone because of its role in controlling female ovary function and male testing, known as gonads.

Structure:

LH is a glycoprotein with a heterodimeric nature. -monomeric unit is a molecule of glycoproteins; one alpha and one beta subunit form the complete, functional protein.

Compared to other glycoprotein hormones, follicle-stimulating hormone (FSH), thyroid – stimulating hormone (TSH), and human chorionic gonadotropin ( hCG), the structure is similar. The protein dimer contains 2 non – covalently connected glycopeptidic subunits (labeledalpha-and beta-subunits).

The LH, FSH, TSH, and hCG alpha subunits are similar and contain 92 amino acids in humans but 96 amino acids in nearly all other vertebrate species (glycoprotein hormones do not occur in invertebrates).

The beta subunits are complex. LH has a 120 amino acid (LHB) beta subunit that confers its specific biological action and is responsible for the specificity of the interaction with the LH receptor. This beta subunit contains an amino acid sequence exhibiting broad homologies to that of the hCG beta subunit and both stimulating the same receptor. Nevertheless, the hCG beta subunit contains an additional 24 amino acids and the two hormones differ in their sugar moiety composition.

The varying composition of these oligosaccharides affects bioactivity and degradation speed. The biological half – life of LH is 20 minutes, shorter than that of FSH (3–4 hours) and hCG (24 hours) The biological half – life of LH is 23 subcutaneous hours or 10 – 12 hours of terminal half – life.

Luteinizing Hormone Function

lh function in women and males:

For women, the ovaries are stimulated by the hormone to produce estradiol. A increase for luteinizing hormone allows the ovaries to release an egg during ovulation within two weeks of a woman’s cycle. If fertilization occurs, the luteinizing hormone will stimulate the luteum corpus which produces progesterone to help the pregnancy.

In males, the luteinizing hormone stimulates testosterone production in the testes from Leydig cells. Testosterone, in effect, increases sperm development and helps accentuate male features — like a deep voice or facial hair growth.

Disorders of the Luteinizing Hormone

Individuals with high luteinizing hormone levels can experience infertility, since the hormone directly affects the reproductive system. For females, too high levels of luteinizing hormones are often related to polycystic ovary syndrome, which produces abnormal levels of testosterone. Many genetic conditions can also cause high levels of the hormone, such as Turner syndrome or Klinefelter syndrome. Individuals who have these conditions often cannot replicate.

Low luteinizing hormone levels can also cause infertility, because insufficient levels can limit sperm production or ovulation cycle. Too little luteinizing hormone prevents ovulation in women, or causes a gonadotropin releasing hormone (GnRH) secretion deficiency in men.