Methadone is often used in the maintenance and detoxification of opioid-dependent pregnant women. This use of methadone during pregnancy is known to be associated with teratogenic effects observed in the progeny. The present study is an attempt to gain insight into possible pathophysiologic mechanism(s) responsible for these teratogenic effects: specifically, a relationship between maternal methadone administration and the content of the endogenous opioid peptide, beta-endorphin, in the brain and pituitary of the rat progeny.

In brief, nulliparous mature female Sprague-Dawley rats received daily injections (5 mg./kg.) of methadone hydrochloride (methadone-treated) or a similar volume of physiological saline (controls), treatment started prior to conception and continued through weaning of the progeny. Following parturition, young rats aged 5, 15, 25 and 75 days were sacrificed by cervical dislocation, and their brain and pituitary removed and dissected. Beta-endorphin immunoreactivity was then determined in the midline telencephalon, diencephalon, medulla-midbrain, and whole pituitary by radioimmunossay. Protein content was also measured. In addition, a number of maternal and progenial morphological parameters were monitored throughout the study.

The results indicate that methadone exposure during gestation and lactation has no significant effect on beta-endorphin content in the whole pituitary or brain regions studied. The results indicate, however, that methadone exposure does significantly reduce protein content in the day 25 diencephalon, and in the day 5 and 15 whole pituitary. The results also tend to support previous studies which have shown methadone exposure to have significant effects on maternal and progenial weight gain, as well as, maternal mortality and perinatal viability.

In conclusion, it appears that maternal methadone exposure has little or no significant effect on beta-endorphin content in the brain or pituitary of the rat progeny; protein content, however, is reduced in both progenial diencephalon and pituitary.

LLU Discipline





Graduate School

First Advisor

Marvin A. Peters

Second Advisor

Cecilia Y. Cheung

Third Advisor

David A. Hessinger

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Methadone -- adverse effects; Rats



Page Count

ix; 141

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives