Abstract
Summary
Pregnant rats on two levels of dietary Na (1.1, 28.7 meq/100 g) were studied along with their nonpregnant counterparts. At the end of gestation, adrenals were removed and studied histochemically for the demonstration of G6PD and sudanophilic lipids. Plasma Na and K concentrations and hematocrit values were taken as supporting data to aid in the interpretation of the histochemical findings.
Either pregnancy or a restricted intake of dietary Na led to slight hypertrophy and hyperplasia of the zona glomerulosa. The combination of Na restriction and pregnancy resulted in extreme hypertrophy and hyperplasia of the zona glomerulosa.
G6PD in the zona glomerulosa increased by 54% due to pregnancy and by 68% due to dietary Na restriction. However, the combined stress of pregnancy plus Na restriction caused a 656% increase in G6PD.
Alterations in the patterns of sudanophilic lipids were noted. Dietary Na restriction or the stress of pregnancy resulted in a slight increase in zona glomerulosa lipid as compared to the nonpregnant controls. However, the combined stress of Na restriction and pregnancy led to lipid depletion in an hypertrophied zona glomerulosa.
It is suggested that the increased activity of G6PD in the zona glomerulosa and the changes in the patterns of lipid distribution are due to an increased stimulation to aldosterone synthesis. The results support the suggestion that Na restriction during pregnancy exhausts the aldosterone-producing capacity of the cells of the zona glomerulosa.
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