Distribution of aromatase activity in brain and peripheral tissues of male sheep: Effect of nutrition

T. P. Sharma, D. Blache, C. E. Roselli, G. B. Martin

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Conversion of testosterone to oestradiol plays a major role in the feedback inhibition of gonadotrophin secretion in male sheep but little is known of the distribution or control of aromatase activity among central and peripheral tissues. Changes in activity at those sites may mediate alterations in the effectiveness of negative feedback following, for example, a change in nutrition. Using a tritiated-water assay, we quantified aromatase in several tissues in mature male sheep, assessed their contribution to oestradiol production, and tested whether activity at each site was affected by a nutritional treatment that stimulates gonadotrophin secretion. Among the brain tissues, the preoptic area had the highest concentration of activity, followed by the hypothalamus, amygdala and cortex. Among the peripheral tissues, liver and testis had the highest activity and, due to their mass, they are the major sources of circulating oestradiol. Pituitary, muscle, kidney and adipose tissues had very low aromatase levels. The nutritional stimulus increased activity in testis but not in liver or brain. We conclude that changes in aromatase activity do not mediate the effects of nutrition on steroid feedback, but aromatisation in testis, liver and brain is important in the endocrine regulation of reproduction in the mature ram.

Original languageEnglish (US)
Pages (from-to)709-715
Number of pages7
JournalReproduction, Fertility and Development
Volume16
Issue number7
DOIs
StatePublished - Dec 1 2004

ASJC Scopus subject areas

  • Biotechnology
  • Reproductive Medicine
  • Animal Science and Zoology
  • Molecular Biology
  • Genetics
  • Endocrinology
  • Developmental Biology

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