Studies on rat pituitary homografts. II. Effects of thyrotropin-releasing hormone on in vitro biosynthesis and release of growth hormone and prolactin

G. Giannattasio, A. Zanini, A. E. Panerai, J. Meldolesi, E. E. Müller

Research output: Contribution to journalArticle

Abstract

A study was made of the effect of TRH, administered in vivo by iv infusion or added in vitro to the incubation fluid, on tissue fragments prepared from normotopic and ectopic pituitaries. The latter were 30-day-old pituitary grafts transplanted under the kidney capsule in hypophysectomized animals. No detectable effect of TRH was found with normotopic glands. In contrast, the neurohormone produced a large increase in GH and PRL biosynthesis in the grafts, as revealed by the rise in hormone content as well as increased incorporation of L-[ 3H]leucine into the two hormones. These effects of TRH 1) are dose related; 2) appear after a latent period of at least 15 min; and 3) persist, although attenuated, for some time after removing the neurohormone. In vitro release of GH and PRL by tissue fragments prelabeled with L-[ 3H]leucine was studied by following the appearance of the radioactive hormones in the incubation fluid. Exposure to TRH produced a prompt, 2-fold or greater increase in hormone release from grafts but not from normotopic gland fragments. The possible mechanisms whereby pituitary somatotrophs and mammotrophs removed from the influence of the central nervous system increase their responsiveness to TRH stimulation are considered.

Original languageEnglish
Pages (from-to)237-242
Number of pages6
JournalEndocrinology
Volume104
Issue number1
Publication statusPublished - 1979

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Fingerprint Dive into the research topics of 'Studies on rat pituitary homografts. II. Effects of thyrotropin-releasing hormone on in vitro biosynthesis and release of growth hormone and prolactin'. Together they form a unique fingerprint.

Cite this