This Article Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by ORTIZ, A. Articles by MISHELL, D. R. Search for Related Content PubMed PubMed Citation Articles by ORTIZ, A. Articles by MISHELL, D. R., JR.

Serum Medroxyprogesterone Acetate (MPA) Concentrations and Ovarian Function Following Intramuscular Injection of Depo-MPA

Department of Obstetrics and Gynecology, University of Southern California School of Medicine and Los Angeles County-USC Medical Center Los Angeles, California 90033

A sensitive radioimmunoassay measuring serum medroxyprogesterone acetate (MPA) has been developed in order to measure and correlate serum MPA concentrations and ovarian function in women following im administration of depo-MPA (DMPA), employing goat anti-MPA-3-(O-carboxymethyl) oxime-bovine serum albumin and MPA-3-(O-carboxymethyl) imino-₁₂₅I-iodohistamine. In the 3 women studied, im injection of 150 mg of DMPA yielded brief initial serum MPA concentrations ranging from 1.5 to 3 ng/ml for a few days. Serum MPA concentrations gradually declined and remained relatively constant at about 1 ng/ml for 2 to 3 months, declined gradually thereafter reaching 0.2 ng/ml during the 6th month and became undetectable (<0.02 ng/ml) about 7 to 9 months following administration. Serum estradiol remained at early to midfollicular phase levels for 4 to 6 months after DMPA injection and rose to preovulatory levels when serum MPA levels fell below 0.5 to 0.25 ng/ml. Ovulation, however, as evidenced by serum progesterone concentrations did not occur, apparently due to suppression of the LH peak by positive feedback inhibition. Prolonged inhibition of cyclic ovarian function following DMPA injection is caused by slow MPA absorption and persists until serum MPA levels have decreased below 0.1 ng/ml or become undetectable about 7 to 9 months after DMPA administration.

This work was supported, in part, by a grant from the Ford Foundation. Drs. M. Hiroi and A. Ortiz were recipients of fellowship grants from the World Health Organization, Geneva, Switzerland.

Received June 11, 1976.

This article has been cited by other articles:

				A. E. Bonny, J. Ziegler, R. Harvey, S. M. Debanne, M. Secic, and B. A. Cromer Weight Gain in Obese and Nonobese Adolescent Girls Initiating Depot Medroxyprogesterone, Oral Contraceptive Pills, or No Hormonal Contraceptive Method Arch Pediatr Adolesc Med, January 1, 2006; 160(1): 40 - 45. [Abstract] [Full Text] [PDF]

				L. P. Ly, P. Y. Liu, and D. J. Handelsman Rates of suppression and recovery of human sperm output in testosterone-based hormonal contraceptive regimens Hum. Reprod., June 1, 2005; 20(6): 1733 - 1740. [Abstract] [Full Text] [PDF]

				K. Pazol, M. E. Wilson, and K. Wallen Medroxyprogesterone Acetate Antagonizes the Effects of Estrogen Treatment on Social and Sexual Behavior in Female Macaques J. Clin. Endocrinol. Metab., June 1, 2004; 89(6): 2998 - 3006. [Abstract] [Full Text] [PDF]

				D. Zhao, D. I. Lebovic, and R. N. Taylor Long-Term Progestin Treatment Inhibits RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted) Gene Expression in Human Endometrial Stromal Cells J. Clin. Endocrinol. Metab., June 1, 2002; 87(6): 2514 - 2519. [Abstract] [Full Text] [PDF]

				I. Schiff, D. Tulchinsky, D. Cramer, and K. J. Ryan Oral Medroxyprogesterone in the Treatment of Postmenopausal Symptoms JAMA, September 26, 1980; 244(13): 1443 - 1445. [Abstract] [PDF]