Flow cytometry was used for comparative in vivo and in vitro analysis of cell populations staining positively for somatostatin. Experiments were carried out with pineals obtained from neonatal, 8- and 15-day-old rats. Pineal cells were obtained by dispersion with collagenase and then processed in a flow cytometer or maintained in culture for 1 or 2 weeks. Identification of somatostatin-immunopositive cell populations was performed using a polyclonal somatostatin antibody and confirmed by indirect immunostaining of cytospun smears with the avidin-biotin-peroxidase method. In vivo, the percentage of somatostatin-positive cells was 60.6 ± 4% in neonatal pineals and declined to 22.2 ± 11 % in 15-day-old animals (p < 0.04). The density of peptide immunostaining decreased in 8-day-old animals but recovered to the neonate levels in 15 day-old animals; homogeneity in the immunopositive population increased with age. Maintenance in culture for 1 week resulted in an increase in positive somatostatin staining in animals of 8 and 15 days with no changes in neonates; however, after 2 weeks of culture, the percent of immunopositive cells decreased from 53.3 ± 6 to 12.2 ± 4% in the older animals and remained unchanged in neonates. We conclude that somatostatin is found in pinealocytes and shows a declining pattern during the perinatal period; this probably implies that the peptide plays a paracrine role important for cell differentiation in these young animals, since maximal cellularity and a high mitotic index occur within the first 3 days of life, and pineal cell differentiation is completed before the end of the third week of extrauterine life.

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.