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Biology of Reproduction, Vol 21, 1153-1162, Copyright © 1979 by Society for the Study of Reproduction
1 Department of Genetics and Development and
Department of Physiology and Biophysics, University of Illinois
and
School of Basic Medical Sciences, University of Illinois College of Medicine,
Urbana, Illinois 61801 The effects of diethylstilbestrol (DES), progesterone, testosterone and vitamin D3, alone or
in various combinations, on the calcium-binding protein (CaBP) concentration, wet weight and
histology of the shell gland were investigated in 7.5-10-week-old chicks. Chicks, which were either
vitamin D deficient or vitamin D replete, were pretreated with DES to differentiate the shell gland.
DES administration was then discontinued for 10 days and then chicks were treated with the
hormones to be tested. In this secondary treatment period, DES increased the levels of CaBP (measured using a specific
radioimmunodiffusion assay) in both vitamin D deficient and vitamin D replete chicks, suggesting
an effect of DES on CaBP largely independent of vitamin D. Progesterone alone had no effect on
CaBP levels, but it inhibited the DES stimulated increase in CaBP in every case tested. In contrast
to this antagonism of CaBP level, the increases in shell gland wet weight and hypertrophy of the
tubular gland cells induced by DES were not inhibited by concomitant progesterone administration. Vitamin D3 alone did not increase CaBP concentration in the shell gland and, when administered with DES to vitamin D deficient chicks, it elicited little if any increase in CaBP level above
that evoked by DES alone. Testosterone had little effect on CaBP level in the shell gland. Despite
chronic injections with estrogen, however, the maximum concentration of CaBP induced in the
DES-differentiated shell gland was only one-sixth the concentration found in the shell gland of the
egg laying hen. These results indicate that CaBP, which is found in numerous organs, may be regulated by
factors in addition to vitamin D3, the predominant regulator in the intestine, and that estrogen and
progesterone may play important roles in modulation of CaBP concentration in the shell gland of
the hen.
Note:
ACKNOWLEDGMENTS
We are grateful to Dr. Robert A. Corradino,
Department of Physical Biology, New York State
Veterinary College, Cornell University, for analyzing
our samples for calcium binding protein content. We
also thank Ortrude K. Dial and Robyn Luke for
excellent technical and secretarial assistance.
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