Publication Date

1977

Document Type

Dissertation/Thesis

First Advisor

Prahlad, K. V.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

LCSH

Mammary glands; Pituitary gland--Transplantation; Exocrine glands; Harderian gland

Abstract

The effects of pituitary isografts in combination with single and fractionated doses of ⁶⁰Co gamma radiation and single and fractionated doses of fission neutrons on mammary and Harderian gland tumorigenesis were studied in the B6CF₁ mouse. Concomitant studies of the cell kinetics in the mammary and Harderian glands were also undertaken. The natural incidence of mammary tumors is about 1% in the hybrid B6CF₁ mouse (C57B1/6J x BALB/cJ/Anl) and shows little increase with low dose single or protracted ⁶⁰Co gamma radiation (Grahn et al., 1972). After exposure to fission neutrons with single doses of 20, 80 and 240 rad, or with 80 or 240 rad given in 24 fractions, the incidence of mammary tumors was somewhat increased. The greatest effect was seen in the 80-rad fission neutron group, but the incidence was only 3.8%. To determine the influence of hormone levels on mammary and Harderian gland tumorigenesis and cell kinetics, two types of experiments were carried out. In the first type the proliferative activity was determined by autoradiographic analysis in the mammary and Harderian glands after isografting two pituitaries under the spleen capsule or after the administration of diethylstilbestrol diphosphate (DES) or exogenous prolactin. in mice with pituitary isografts the labeling index (percent of cells in DNA synthesis) in the mammary gland epithelium was increased 10-fold. This increased synthetic activity was maintained up to at least 525 days post-implantation. Using continuous labeling techniques, it was found that the total cell cycle time as well as the synthetic phase of the cell cycle was decreased in the mammary tissue cells. After 7 days of administration of 1 μg/L of DES in the drinking water, the DNA synthetic activity was increased over 10-fold. The presence of pituitary isografts did not have any effect on the proliferative activity in the Harderian gland at 22 or 525 days post-implantation, but prolactin given exogenously for 3 days caused about a 2-fold increase in the DNA synthetic activity. In the second type of experiment, mice with pituitary isografts were exposed to a single dose of 20 or 80 rad fission neutron or to 90 or 269 rad ⁶⁰Co gamma radiation. The results showed that in comparison with unirradiated control mice, with or without grafts, two major effects of the combined treatment of pituitary isografts and fission neutrons on tumorigenesis occurred: (1) there was a reduced latent period and an increased incidence of mammary tumors, and (2) for Harderian gland tumors there was (a) a reduced latent period, (b) a marked increase in the incidence (e.g. from 2.5% in controls to about 37% after a single dose of 80 rad fission neutrons), and (c) an increase in the number of Harderian gland tumors with metastases.

Comments

Includes bibliographical references.||Includes illustrations.

Extent

vii, 72 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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