Human Luteinizing hormone (LH) is a glycoprotein hormone secreted by the anterior pituitary. This hormone is composed of α and β subunits.
The amino acid sequence of α-LH is essentially identical to that of other hormones including follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH) and human Chorionic Gonadotropin (HCG). It is β subunit of LH that confers the biological and immunochemical specificity of the hormone.
Human Chorionic Gonadotropin (HCG) is a glycoprotein hormone secreted by the developing placenta shortly after fertilization. During normal pregnancy, HCG can be detected in urine as early as 7 days following conception, doubling every 1.3 to 2 days. At the time of the last missed menstrual period, urine HCG levels are about 100mlU/ml with peak levels of 100, 000 to 200, 000mlU/ml seen at the end of the first trimester. The presence of HCG soon after conception and its subsequent increase in concentration during early gestational growth make it an ideal marker for the early detection of pregnancy.
