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 Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Smith, V. G. Articles by Veira, D. M. Search for Related Content PubMed PubMed Citation Articles by Smith, V. G. Articles by Veira, D. M.

Response of Bovine Serum Prolactin and Growth Hormone to Duodenal, Abomasal, and Oral Administration of Thyrotropin-Releasing Hormone¹

Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1

ABSTRACT

Thyrotropin-releasing hormone was injected into the duodenum of two 500-kg steers, placed into the abomasum of two prepubertal bulls, and fed to four bull calves (1 to 3 wk of age) to test the effect on concentrations of prolactin and growth hormone in blood serum. Before 20 and 200 mg of thyrotropin-releasing hormone were injected into the duodenum, prolactin in serum averaged 7.5 and 9.4 ng/ml and increased to 52.5 and 129.6 ng/ml at 45 and 35 min after treatment. Average growth hormone concentration of serum was increased also, but the response was more variable than prolactin. Peak concentrations of prolactin and growth hormone in blood serum were 5 to 10 times greater after treatment with thyrotropin-releasing hormone (40 mg/100 kg body weight into abormasum) than before treatment. Within 30 min after oral administration of thyrotropin-releasing hormone (0, .5, 1, and 2 mg/kg body weight) growth hormone concentration of serum was 30, 306, 356, and 317% greater than pretreatment. Prolactin concentration of serum, however, was increased in only one calf.

¹ This work was supported in part by Ontario Ministry of Agriculture and Food, B. H. Bull Fund and N. R. C. Grant A-6247.