Experiments with Hypophyseal Lactogenic Hormone on Normal Ovariectomized and Hypophysectomized Dogs

The present report deals with the effects of the lactogenic hormone in normal dogs and in dogs following the removal of ovaries and hypophysis. The hormone used in this investigation was obtained in powder form from an acid-acetone extract of the anterior pituitary. One mg. of the dry powder was equivalent to 40 mg. of fresh anterior lobe. Gonad-stimulating hormone could not be demonstrated in 100-mg. doses of such powders tested on immature pigeons and rats. No attempt was made in these experiments to free these powders of some slight contamination with growth hormone, although potent isoelectric precipitations at pH 6.4 have yielded growth-free lactogenic hormone. Full details of the method of preparation are submitted separately. The results are shown in tabular form. It was found that 2 subcutaneous injections representing a total of 20 mg. of crude lactogenic hormone sufficed to cause the secretion of milk in normal parous and non-parous mature bitches. Lactation was obtained in 3 bitches ovariectomized one day previous to administration of the hormone. The hormone induced lactation in a single bitch hypophysectomized one week prior to treatment. The mammary glands of this animal were well developed and did not yet show regressive changes as the result of hypophysectomy. Two other hypophysectomized dogs failed to respond, although several times the amount of the hormone found necessary to induce lactation in normal dogs was injected in these animals. The failure, however, to obtain lactation with the hormone in these 2 dogs may probably be ascribed to lack of mammary development, inasmuch as one of these animals was sexually immature with infantile mammae, while the other was a senile bitch with atrophied mammae and ovaries. All dogs in which lactation was induced continued secreting milk for about 2 weeks after the last injection. Even a non-parous bitch was stripped of approximately 100 cc. of milk on 3 consecutive days. A mother that had been removed from her litter and had been dry for a week was brought back to full lactation to continue suckling.