Publication Date

1988

Document Type

Dissertation/Thesis

First Advisor

Conway, Sonya

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

LCSH

Somatotropin; Sex (Biology)

Abstract

The regulation of the sexual dimorphic pattern of growth hormone (GH) secretion between the male and female rat was studied by examining GH autofeedback characteristics. The model used was the capacity of Intraventricularly (ivt) administered oGH to suppress a GH surge induced by clonidine (CLON). Studies were undertaken in male and female rats under varying diurnal, gonadal hormone, and hypothalamic hormone conditions. These studies demonstrated that normal or adult ovariectomized (OVXed) female rats are less sensitive to CLON stimulation and ivt oGH inhibition of GH secretion than males or prepubescent OVX females. In addition, exposure to ovarian hormones at puberty may be important in establishing the difference in timing and amplitude of GH surges in male and female rats. Female rats may have a stronger SRIF inhibition of GRH release than males. Testosterone may not directly affect CLON sensitivity or GH feedback, but may influence the male pattern of secretion at a site preceding alpha-2-adrenergic neurons. Further, there may be diurnal variation in the control of GH secretion in the female. Finally, these results support a role for GRH in GH negative feedback system.

Comments

Includes bibliographical references (pages 116-134)

Extent

ix, 167 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.

Media Type

Text

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