Steroid modulation of response of plasma bicarbonate concentration to NH4Cl loading: gamma distribution analysis.
Studies have been carried out in awake chronically cannulated adrenalectomized rats subjected to steroid replacement protocols. Our objective was to determine the effects of mineralocorticoid or glucocorticoid or combined replacement on acid-base composition of the extracellular fluid compartment in response to an acute ammonium chloride acid load. We obtained six blood samples from each animal over a 26-h period and, with the help of a specially derived mathematical model, we were able to obtain a continuous dynamic assessment of changes of plasma bicarbonate concentration during induction and recovery of the metabolic acidosis. Assessment of minimum values for plasma bicarbonate concentration, time to reach the minima, and time for 90% recovery showed that dexamethasone did not exert as much protection as aldosterone. The approach we have used, in a sense being a continuous display of plasma bicarbonate concentration, should be useful in further exploring the nature of the interrelations between acid production, net acid excretion, and the resultant plasma acid-base composition.
D000315:Adrenalectomy; D000643:Ammonium Chloride / Q000008:administration & dosage*; D000818:Animals; D001639:Bicarbonates / Q000097:blood*; D004750:Enteral Nutrition; D005938:Glucocorticoids / Q000494:pharmacology*; D008297:Male; D008901:Mineralocorticoids / Q000494:pharmacology*; D008954:Models, Biological; D051381:Rats; D011919:Rats, Inbred Strains
D001639:Bicarbonates; D005938:Glucocorticoids; D008901:Mineralocorticoids; D000643:Ammonium Chloride