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Specific Binding of Human Chorionic Somatomammotropin in Rat Liver and Mammary Gland
Author(s) -
Deguchi Masaki,
Mochizuki Matsuto,
Tojo Shimpei
Publication year - 1981
Publication title -
asia‐oceania journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 50
eISSN - 1447-0756
pISSN - 0389-2328
DOI - 10.1111/j.1447-0756.1981.tb00539.x
Subject(s) - medicine , endocrinology , prolactin , mammary gland , lactation , hormone , biology , heterologous , chemistry , pregnancy , biochemistry , genetics , cancer , breast cancer , gene
The binding of 125 I‐labeled hCS was examined in cell membrane fraction obtained from rat liver and mammary gland. The specific binding of 125 I‐labeled hCS was determined in pregnant rat liver (binding capacity: 1.4 times 10 ‐12 mol/mg protein), nonpregnant liver (0.4 times 10 ‐12 ) and lactating mammary gland on the 7th post‐partum day (0.06 times 10 ‐12 ). These bindings were displaced from liver or mammary gland by hormones capable of stimulating lactation (i.e., prolactins and human growth hormone). “Lactogenic activity” was investigated in pregnant rat serum by heterologous radioreceptor assay using 125 I‐labeled hCS and cell membranes of the rat liver. Two peaks of “lactogenic activity” were seen in rat serum throughout pregnancy. The first peak (1321 + 503 ng hCS equivalents/ml) was at mid‐pregnancy and the second peak (1232 + 819 ng) was near term. It appears that this activity in serum is mainly due to a placental lactogenic hormone in rats.