16-alpha-ethyl-21-hydroxy-19-nor-4-pregnene-3-20-dione and Weight-Gain

Female Sprague-Dawley rats were treated IM with 0, 2.5, 25, and 50 micrograms of clenbuterol HCl/kg of body weight/d for 21 days. In all treated rats, significant increase in body weight gain (P < 0.05) and improvement in feed conversion ratio (P < 0.05) were recorded. Hydrometra was observed in the uterus of treated rats, and histologically, it was possible to see dilatation of luminal glands and ovarian alterations. Clenbuterol treatment induced significant (P < 0.05) increase in uterine estrogen receptor concentration of rats treated with the 2 higher doses. Treatment apparently failed to enhance the rate of oxidative and conjugative biotransformations, except for glucuronidation of p-nitrophenol (P < 0.05). On the basis of the data obtained, we could affirm that high doses of clenbuterol affect the female reproductive system of rats inducing, almost in part, estrogen-like modifications, but probably by a different mechanism of action correlated to intense adrenergic stimulation.

Topics: 7-Alkoxycoumarin O-Dealkylase; Aniline Hydroxylase; Animals; Body Weight; Clenbuterol; Cytochrome P-450 CYP1A1; Cytochrome P-450 Enzyme System; Cytosol; Dose-Response Relationship, Drug; Drug Administration Schedule; Estradiol; Female; Glucuronosyltransferase; Glutathione Transferase; Liver; Microsomes, Liver; Oxidoreductases; Pregnenediones; Progesterone; Progesterone Congeners; Rats; Rats, Sprague-Dawley; Receptors, Estrogen; Receptors, Progesterone; Uterus; Weight Gain