Production of Aldosterone in Male Rats with Inherited Diabetes Insipidus (Brattleboro Strain)

Abstract

Plasma concentration, metabolic clearance rate and in vitro adrenal production of aldosterone were measured in Brattleboro male rats with inherited diabetes insipidus (DI) and in Long-Evans male rats (LE) as controls. Plasma concentration of aldosterone was significantly lower (-48.3%) in DI rats than in LE rats. Metabolic clearance rate of aldosterone was not statistically different between Brattleboro and Long-Evans rats, suggesting that the in vivo production rate of aldosterone was reduced by half in DI rats. Conversely, the basal in vitro production of aldosterone by adrenal tissue was similar in the two groups of rats. The reason for impairment of the in vivo production of aldosterone by Brattleboro rats congenitally lacking vasopressin is discussed. It is suggested that despite possibly indirect influence on the factors involved in the control of aldosterone secretion, mainly ACTH and potassium, vasopressin effects might occur in situ on the adrenal glomerulosa cells.

Effect of Sodium Deprivation on Plasma and Adrenal Concentrations of Aldosterone and Corticosterone in the Brattleboro Homozygous Rat

“…The present results showed that, under normal sodium diet and in resting conditions, plasma concentration and adrenal content of aldosterone of the Brattleboro rat were about two fold lower than those found in the Long-Evans rat. This observation confirms our (Laulin et al, 1984) and other previous reports (Möhring et al, 1974;Möhring et al, 1978;Milne et al, 1982;Opava-Stitzer et al, 1982).…”

“…In animals fed a normal diet, water intake, urine output and water balance were greatly higher in Brattleboro than in Long-Evans rats; moreover, while urinary sodium and potassium concentrations and urinary osmolality were much lower, excretion and balance of sodium and potassium were slightly but significantly higher in Brattleboro than in control rats. These results agree with our and other previous reports (Valtin and Schroeder, 1964;Lee and Williams, 1972;Balment et al, 1976;Möhring et al, 1978;Laulin et al, 1984). Interestingly enough we found that the effects of ten days of dietary sodium deprivation were about in the same order of magnitude in the two groups of rats; i.e.…”

“…So the Brattleboro/Long-Evans differences observed in normal diet fed rats no more appeared in sodium deprived rats. We have previously shown that the metabolic clearance rate (MCR) of aldosterone was not significantly different in Brattleboro rats com-pared with Long-Evans rats fed a normal sodium diet (Laulin et al, 1984); neither it is changed by a decrease in sodium diet in the normal rat (Bojesen, 1966). Nevertheless, a possible role for sodium depletion to affect differently the aldosterone MCR needs to be investigated in the Brattleboro rat.…”