Calcitonin is expressed in gonadtropes of the anterior pituitary gland: Its possible role in paracrine regulation of lactotrope function

Y. Ren, J. Chien, Y. P. Sun, G. V. Shah

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Previous studies from this laboratory have shown that salmon (S) calcitonin (CT)-like immunoreactive peptide (CTI) is synthesized and secreted by the anterior pituitary (AP) gland. These studies also co-localized CTI to gonadotropes, and demonstrated that SCT is a potent inhibitor of lactotrope function. However, the molecular structure of putative gonadotrope-derived CTI that inhibits lactotrope function has not been defined. The present studies cloned CT cDNA (pit-CT cDNA) from a mouse gonadotrope LβT2 cell line using RT-PCR and rapid amplification of cDNA ends (RACE) techniques. Alignment of nucleotide sequences of pit-CT and mouse CT revealed greater than 99% homology between the sequences. The pit-CT cDNA was ligated into a mammalian expression vector, and the construct was transfected into LβT2 cells. Two stable transfectant cell lines (CT.U6/ A and B) were obtained by selection in G418. Subsequent S1-nuclease protection assay and immunocytochemistry results have shown that: (1) pit-CT peptide expressed by CT.U6 cell lines immunoreacted with GCT1-anti-SCT serum; (2) secretions of CT.U6 cells inhibited prolactin (PRL) release, PRL mRNA abundance and DNA synthesis of PRL-secreting GGH3 cells; and (3) CT.U6-induced inhibition was abolished by GCT1-anti-SCT serum. The studies also generated a riboprobe from the cloned pit-CT cDNA, and localized CT mRNA expression in gonadotropes of rat AP gland by in situ hybridization histochemistry. These results demonstrate that pit-CT mRNA is closely homologous to mouse CT mRNA; it is expressed by gonadotropes of the rat AP gland, and the peptide may significantly affect lactotrope function by inhibiting PRL release and cell proliferation.

Original languageEnglish (US)
Pages (from-to)217-228
Number of pages12
JournalJournal of Endocrinology
Volume171
Issue number2
DOIs
StatePublished - Jan 1 2001
Externally publishedYes

Fingerprint

Anterior Pituitary Gland
Calcitonin
Complementary DNA
Prolactin
Messenger RNA
salmon calcitonin
Cell Line
Peptides
Nuclease Protection Assays
Sequence Homology
Molecular Structure
Serum
In Situ Hybridization

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

Cite this

Calcitonin is expressed in gonadtropes of the anterior pituitary gland : Its possible role in paracrine regulation of lactotrope function. / Ren, Y.; Chien, J.; Sun, Y. P.; Shah, G. V.

In: Journal of Endocrinology, Vol. 171, No. 2, 01.01.2001, p. 217-228.

Research output: Contribution to journalArticle

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