Following a period of estrogen priming, the spayeds hamster displays normal estrous behavior within 2–3 h after subcutaneous placement of progesterone. To determine the locus of the estrogen priming effect, a single midline implant of estradiol, fused within the lumen of a 27 or 23 gauge hypodermic tube, was stereotaxically implanted into various sites of the hypothalamus of females which had been spayed 9 days. At the time of lights out on the 3rd and on the 7th day following implantation, all females were injected with 200 µg of progesterone in 0.1 cm3 of propylene glycol. Females were tested for estrous behavior by placing them with experienced males for a period of 10 min prior to progesterone injection, and at 90 min, 2, 3, 4, 6 and 10 h thereafter. A 23 gauge estradiol implant provides a sufficient priming treatment if the hormone is placed in the anterior dorsal hypothalamus in an area including: the dorsal half of the anterior hypothalamic area, the ventral third of the filiform nucleus, and the area anterior to the dorsomedial nucleus; extending 0.5 mm laterally and 1.5 mm in the anterior-posterior plane and 1.0 mm in the dorsal-ventral plane. Implants containing radioactive estradiol indicated that the hormone did not diffuse to other areas of the hypothalamus. A 23 gauge estradiol tube was ineffective if implanted into other areas of the hypothalamus or if placed subcutaneously. A 27 gauge estradiol implant into the sensitive area did not constitute a sufficient priming treatment.

This content is only available via PDF.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.