| Abstract: | Chromatographic separation of multiple renin substrates was carried out to study the effect of pregnancy and oral contraceptives (OCs) in women. Blood plasma proteins were separated on a Sephadex G-200 column and the amount of renin substrate in each fraction was determined. The molecular weight of the renin substrate peaks was estimated by comparison with the elution position of proteins of known molecular weight. Normal nonpregnant women revealed the presence of 2 renin substrates: a major 1 with a molecular weight of 65000 and 1 amounting to 3-5% of the quantity of the major peak with a molecular weight of 450000-500000. In women taking OCs the same 2 peaks were seen but the quantity of each was increased markedly. In pregnant women at term, a 3rd renin substrate of intermediate size was seen (molecular weight 350000 daltons). The quantities of the intermediate and low molecular weight renin substrates were found to be greatly increased in pregnancy. |
