Adrenal function parameters and body weight gains in young rats reared with or without mother animal.

Abstract

In comparison to young animals maintained in the presence of mother animal, weaning of young rats on day 15 decreases body wt. and average rate of corticosterone production, increases biological activity of plasma corticosterone estimated tentatively by means of relative thymus wt; and increases liver capacity to hydrogenate-A ring of corticoids. No change was found in average total plasma corticosterone level. Correlation studies revealed that in prematurely weaned rats 76.5% of variation in wt. gains may be explained by adrenal function parameters in comparison to only 4.4% in young rats maintained with the mother animal. Within the group of young prematurely weaned rats relatively lower adrenal system activity seems to favor larger weight gains.