Administration of testosterone to wether lambs: effects on protein and energy metabolism and growth hormone status

Gerald Lobley, A Connell, Vivien Buchan, P A Skene, J M Fletcher

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The effects of episodic infusion of testosterone into the vascular system on energy expenditure, nitrogen retention and whole body protein synthesis (determined from [1-14C]leucine kinetics) were studied in castrated male lambs under conditions of controlled food intake. Comparisons were made between a 10-day control period and a 10-day treatment period for each lamb. Infusion of testosterone produced a significant increase in heat production, but the magnitude (198 kJ/day, +2.5%) was less than the differences in energy expenditure expected between entire and castrated male ruminants. The retention of nitrogen improved by 1.24 g/day (+22%) in response to the administration of androgen, and this was accompanied by a decrease in amino acid oxidation. Total protein synthesis also declined, and the anabolic nature of testosterone supply must, therefore, be effected through a reduction in the breakdown of protein, the mechanism being similar to that proposed for certain anabolic steroids and the beta-agonist, clenbuterol. Contrary to other reports, the presence of testosterone had no effect on the plasma concentration of GH.
Original languageEnglish
Pages (from-to)439-445
Number of pages7
JournalJournal of Endocrinology
Issue number3
Publication statusPublished - 1 Dec 1987



  • Animals
  • Energy Metabolism
  • Growth Hormone
  • Leucine
  • Male
  • Nitrogen
  • Orchiectomy
  • Protein Biosynthesis
  • Sheep
  • Testosterone

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