• Hammer, Ronald P (PI)

Project: Research project

Grant Details


This project will examine the interaction between sex hormones, opiate
receptors and endogenous opioid compounds in the medial preoptic area
(MPOA) of the rat during perinatal development and during adult life.
Opiate receptors in this region exhibit a sex difference shortly after
birth and respond dynamically to hormonal changes during the estrous cycle
of females. The development of MPOA opiate receptors may be sex hormone
dependent. This project will examine the ontogeny of MPOA opiate receptors
by quantitative densitometry of [3H]naloxone autoradiographs of the MPOA
from intact male and female rats from the time of birth to 6 days of age
(the period during which the sex difference develops), and in castrated or
tamoxifen-treated males and testosterone- or dihydrotestosterone-treated
females during the early postnatal period. The ontogeny of the endogenous
opioid compounds, methionine- and leucine enkephalin and Beta-endorphin,
will be examined during the early postnatal period using
immunohistochemical procedures. Autoradiographic techniques will also be
used to study the influence of various sex hormones which mimic the estrous
cycle on MPOA opiate receptor binding in adult gonadectomized females and
males. The adult hormonal manipulations will elucidate the hormonal
mechanism involved in opiate receptor density variations during the estrous
cycle and examine the "fixed" or dynamic nature of opiate receptors in the
male hypothalamus. Endogenous opioid systems may be involved in the control of reproductive
behavior and/or hormonal cyclicity. These investigations of the ontogeny
and adult function of hypothalamic opioid systems represent an initial step
in our understanding of the control mechanism. The results may elucidate
the mechanism of normal and aberrant reproductive function and of narcotic
effects on reproductive function.
Effective start/end date4/1/859/30/88


  • National Institutes of Health


  • Medicine(all)


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