HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by von Berswordt-Wallrabe, R. Articles by Turner, C. W. Search for Related Content PubMed Articles by von Berswordt-Wallrabe, R. Articles by Turner, C. W.

Successful Dihydrotachysterol (A.T. 10) Replacement Therapy in Lactating Thyro-Parathyroidectomized Rats¹

Department of Dairy Husbandry, University of Missouri, Columbia

ABSTRACT

Thyro-parathyroidectomy (TPEC) was performed in ten albino rats on Day 4, in 66 albino rats on Day 7 of lactation. Replacement therapy was only partially successful when 187.5 µg. dihydrotachysterol (A.T. 10)/day was injected subcutaneously from Days 5–13. Completely successful replacement therapy was achieved when 60, 80, and 100 µg. A.T. 10/100 g. body weight/day were given orally from Days 7–13 of lactation. All animals received daily 3.5 and 3 µg. thyroxine (T4)/100 g. per day, respectively, from Day 4 or 7 until end of experiment. Criteria for lactational performance were prenursing litter weight and milk yield on Days 14 and 15–21. Nursing was standardized with 1 U.S.P. unit oxytocin (OXT), injected subcutaneously from Days 14–21 immediately before each nursing. Discontinuation of A.T. 10 in TPEC lactating rats on Day 13 resulted in fatal attacks of tetany in 35 of 66 of the superior lactating rats between Days 16 and 21. In 11 rats nonfatal attacks of tetany, combined with reduced lactational performance, occurred during the same period. Eleven other rats not observed to show signs of tetany were believed to have been completely para-thyroidectomized. It is suggested that lower losses of serum Ca due to poor lactational performance (as indicated by depressed litter weight and milk yield on Day 21) were responsible for the absence of tetany. Nine rats with lactational performance until Day 21 similar to intact control rats were considered to have accessory parathyroid glands. Rats successfully TPEC lost body weight, whereas intact controls gained slightly.

¹ Contribution from Missouri Agricultural Experiment Station. Journal Series No. 2166. Approved by the Director.

² Research Fellow, Department of Animal Physiology and Animal Nutrition, University of Goettingen, West Germany, and Medical Fellow of Population Council. Present address: University of Goettingen.