Sialoglycoprotein Hormones

Several sialoglycoprotein hormones are present in relatively minor but essential quantities in the plasma. As early as 1948, it was reported that the biological activity of cmde chorionic and pituitary gonadotro- 

Percent sialic Biological activity acid in vivo 

Erythropoietin Induces normal erythrocyte development 13-14 Inactivated No effect Lowy et aL, 1960 Schooley and Garcia, 1971 

Human pituitary luteinizing hormone Acts on interstitial cells of both ovaries and testes. Inactivated Enhancement Braunstein et al., 1971 

Human chorionic gonadotropin Maintaining growth of corpus luteum during pregnancy stimulates Leydig tissue. 8.5 Inactivated No effect Barr and Collee, 1967 Van Hall et aL, 1971 Kunii, 1971 

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The human pituitary luteinizing hormone has been found to be a sialoglycoprotein, with a and /3 subunits differing in their sialic acid content (Shownkeen et al., 1973). 

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