Further to my last, here is a good read in case you are interested. This is the link:
http://911papers.virtualave.net/classical_sciences/biology/Gynecomastia.htm
Furthermore this is a quote from the paper,
Many drugs can cause gynecomastia by several mechanisms. The drugs can either act directly as estrogens or cause and increase in plasma estrogen levels. "Boys and young men are particularly sensitive to estrogen, and can develop gynecomastia after the use of dermal ointments containing estrogen or after the ingestion of milk or meat from estrogen-treated animals."(Isselbacher, 2038) Some examples of drugs that may have cause gynecomastia include Cannabinoids (methane and marijuana), Psychotropics (pheno-thiazine, butyrophenone and reserpine), Antihypertensives (reserpine, alpha-methyldopa and spironolactone), Cardiac (digitalis), Gastrointestinal (cimetidine, metoclopramide and domperidone), Antituburculous (isoniazid), Cytoxic (cyclophospha-mide, mustine, vincristine and mitotane) and Hormonal (sex steroids, gonadotropins and antiandrogens). Use of these drugs, however, will rarely cause gynecomastia. In some instances, the feminization is due to effects of drugs on liver functions.
YOU WANT STUDIES, then use human studies. We are not rats.