Targeted cytotoxic analogue of luteinizing hormone-releasing hormone (LH-RH) only transiently decreases the gene expression of pituitary receptors for LH-RH

M. Kovacs, A. V. Schally, B. Csernus, R. Busto, Z. Rekasi, A. Nagy

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

A cytotoxic analogue of LH-RH, AN-207, consisting of 2-pyrrolinodoxorubicin (AN-201) linked to carrier [D-Lys6]LH-RH, was developed for targeted therapy of cancers expressing LH-RH-receptors. To determine its possible side-effects on the pituitary gland, we investigated the gene expression of pituitary LH-RH-receptors and LH secretion in ovariectomized female and normal male rats after treatment with the maximum tolerated dose of AN-207. The effect of AN-207 on the gene expression of the pituitary GH-RH-receptors and GH secretion was also assessed in male rats. Five hours after a single i.v. injection of AN-207 at 175 nmol/kg, there was a 39-51% decrease in mRNA expression for the pituitary LH-RH-receptors in male and female rats. The carrier, at an equimolar dose, caused a similar reduction (37-39%), whereas the cytotoxic radical AN-201, at an equitoxic dose (110 nmol/kg), produced only a 12-24% decrease (NS) in the mRNA expression of LH-RH-receptors. AN-207 and the carrier analogue induced a comparable 90-100-fold increase in serum LH concentrations in male rats, and the same 12-fold elevation in OVX rats at 5 h. Seven days after treatment with AN-207, the mRNA levels for the LH-RH receptors and the serum LH concentration were back to normal in both sexes. AN-207, the carrier, and AN-201 had no significant effect on the expression of mRNA for GH-RH-receptors in the pituitary. In vitro, a continuous perfusion of pituitary cells with 10 nM AN-207 did not affect the hormone-releasing function of the targeted LH cells or the nontargeted GH cells. Our results demonstrate that cytotoxic LH-RH analogue AN-207, at the maximum tolerated dose causes only a transient decrease in the gene expression of the pituitary LH-RH receptors, and the levels of mRNA for LH-RH receptor fully recover within 7 days. Moreover, the carrier hormone moiety, and not the cytotoxic radical in AN-207 is responsible for this transient suppression. Our findings suggest that the therapy with cytotoxic LH-RH analogues will not inflict permanent damage to pituitary function.

Original languageEnglish (US)
Pages (from-to)5-13
Number of pages9
JournalJournal of Neuroendocrinology
Volume14
Issue number1
DOIs
StatePublished - 2002
Externally publishedYes

Keywords

  • Cytotoxic LH-RH analogue
  • GH
  • GH-RH-receptor mRNA
  • LH
  • LH-RH-receptor mRNA

ASJC Scopus subject areas

  • Endocrinology
  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Targeted cytotoxic analogue of luteinizing hormone-releasing hormone (LH-RH) only transiently decreases the gene expression of pituitary receptors for LH-RH'. Together they form a unique fingerprint.

Cite this