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Table 1 Parallelisms between placental implantation and hemochorial placentation in primates, sugar structure on CG or LH, and relative brain masses

From: hCG, the wonder of today's science

Species Placentation characteristics Depth of Invasion Molecule produce; # oligosaccharides (oligos); pI of dimer; circulating 1/2-life; relative biopotency Brain mass(% body weight) First appearance (million years ago)
Humans Hemochorial 1/3 rd myometrium CG; 8 oligos; pI 3.5; 1/2-life 36 h, 109X 2.4% 0.1
Advanced simian primates Hemochorial 1/10th myometrium CG; 6 oligos; pI 4.9; 1/2-life 6 h; 18X 0.74% 20
Early simian primates Hemochorial through decidua CG; 5 oligos; pI 6.3; 1/2-life 2.4 h; 7.3X 0.17% 37
Prosimian primate Epitheliochorial non-implanting LH; 3 oligos; pI 9.0; 1/2-life 0.33 h; 1X 0.07% 55
  1. The circulating 1/2-life of Advanced simian primate and Early simian primate CG was calculated using an equation that consider number of oligosaccharides on LH and human CG and the known circulating 1/2 life. C1/2 is circulating 1/2-life and number of oligosaccharides is #O, CR = 2.4#O x 1.9. Table summarizes published data (34-45)