Promotes spermatogenesis and ovulation by stimulating the testes and ovaries to synthesize steroids. Heterodimer of a common alpha chain and a unique beta chain which confers biological specificity to thyrotropin, lutropin, follitropin and gonadotropin. Microheterogeneity at Asn-33. O-glycosylation appears to be responsible for the beta subunit contribution to the difference in LH-receptor binding activity between LSH-B and CG-B. Belongs to the glycoprotein hormones subunit beta family.