The effect of androgen and estrogen on food intake and body weight in rats--age dependency.

The age dependency of changes in food intake and body weight in Wistar rats after androgen and estrogen treatment was followed. The 5 age categories of female rats were treated by androgen and the 6 age categories of male rats were treated by estrogen. The androgen treatment induced an expressive increase in weight gains in all age categories of female rats, except the 1st (after birth), during 25 days from the beginning of the experiments. The increase of weight gains resulted in significantly higher body weight on the 25th day of experiments in the experimental rats. The differences in weight gains among the individual experimental groups after androgen treatment show a rising effect with the age of the animals. There was only a slight increase of food intake in the older experimental groups during the androgen treatment. The estrogen treatment in male rats induced an expressive decrease in weight gains in the 2nd age category (after weaning) and losses of body weight in older experimental groups during 20 days from the beginning of the treatment. The body weight of experimental animals on the 20th day was significantly lower than in the control ones. The losses of the body weight after the estrogen treatment rose with the age of the rats. The food intake was also considerably decreased by estrogen treatments, approximately equally in all experimental groups. The comparison of magnitude of the changes in food intake and body weight after androgen and estrogen treatments indicates that the primary effect of these hormones is their anabolic or catabolic activity which secondarily induces the changes in food intake and its utilization.