Response to the maternal pheromone in the rat as protection against necrotizing enterocolitis

The maternal pheromone and deoxycholic acid in the survival of preweanling rats

Preweanling rats selectively approach and consume pheromone-containing maternal feces. This selectivity suggests that the consumption of maternal feces might be important for the growing pup. We tested the hypothesis that such feces, because of their high deoxycholic acid content, may protect against acute enteritis. A series of experiments was carried out in which pups were denied access to maternal feces. These pups died more often from acute enteritis than control pups. Additional confirmation of the hypothesis was obtained when feces-denied young fed deoxycholic acid showed a significantly lower mortality than feces-denied young fed laboratory chow alone.

The maternal pheromone and deoxycholic acid in relation to brain myelin in the preweanling rat

We examined the lipid composition of blood and myelin in preweanling rats denied access to maternal feces. Levels of triglycerides and free fatty acids in the blood were reduced and in the brain the amount of myelin and the phospholipid concentration in myelin were also reduced. The addition of deoxycholic acid to ordinary laboratory chow prevented these deficiencies. We conclude that response to the maternal pheromone and the subsequent ingestion of deoxycholic acid through maternal feces promotes the deposition of normal brain myelin.

The maternal pheromone and bile acids in the lactating rat

Bile was drawn from virgin rats and from postpartum rats that were with young for 5, 12, 21, and 30 days, respectively. The bile thus drawn was analyzed enzymatically after chromatographic separation to test an hypothesis relating cholic acid and one of its metabolites, deoxycholic acid, to the appearance of the maternal pheromone. Our finding that cholic acid, but not deoxycholic acid, reached a peak that was tied specifically to the period of pheromonal emission led us to advance a revised hypothesis. We now think that cholic acid alone, or more likely a cholic metabolite other than deoxycholic acid, underlies the appearance of the pheromone.