The site of action of intrahypothalamic estrogen implants in feminine sexual behavior: an autoradiographic analysis
Estrogenic stimulation of the ventromedial hypothalamus is sufficient to prime progesterone-facilitated estrous behavior in ovariectomized rats. To determine precisely the site(s) of estrogenic stimulation and the locus of its priming action on estrous behavior, we used steroid autoradiographic methods to assess the diffusion of (/sup 3/H)estradiol ((/sup 3/H)E/sub 2/) from behaviorally effective implants diluted 1:300 with cholesterol. Ovariectomized rats received (/sup 3/H)E/sub 2/-cholesterol implants aimed at the ventromedial hypothalamic nucleus (VMN). Females were tested twice for feminine sexual behavior after stereotaxic surgery. They received progesterone on the day of behavioral testing. Animals were killed on the day after the second behavior test, cannulae were removed, and the brains were frozen rapidly and processed for autoradiography. Five of eight females with bilateral implants aimed at the VMN exhibited female sexual behavior in at least one of the two tests. Of these, four also showed proceptive behavior. Histological examination of brain sections indicated that behaviorally effective implants were located in, or adjacent to, the central portions of VMN. Implants from nonreceptive animals were located at the extreme anterior or posterior aspects of the VMN. The data collected are consistent with the view that estrogen acts within a sharply defined region of the VMN to prime estrons behavior.
- Research Organization:
- Rockefeller Univ., New York, NY
- OSTI ID:
- 6171228
- Journal Information:
- Endocrinology; (United States), Vol. 111:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ESTRADIOL
TISSUE DISTRIBUTION
HYPOTHALAMUS
STIMULATION
RATS
BEHAVIOR
AUTORADIOGRAPHY
CHOLESTEROL
DIFFUSION
ESTROUS CYCLE
IMPLANTS
MATING
OVARIES
SURGERY
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMALS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DISTRIBUTION
ESTRANES
ESTROGENS
FEMALE GENITALS
GONADS
HORMONES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEDICINE
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
RODENTS
STEROID HORMONES
STEROIDS
STEROLS
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques