Document Detail

Endothelin-like immunoreactivity in lactotrophs, gonadotrophs, and somatotrophs of rat anterior pituitary gland are affected differentially by ovarian steroid hormones.
MedLine Citation:
PMID:  11394645     Owner:  NLM     Status:  MEDLINE    
It has been previously found that all hormone-producing phenotypes of the anterior lobe of the pituitary gland are capable of producing endothelin (ET)-like substances. The aim of this study was to determine whether the expression of ET-1-like peptides in lactotrophs, gonadotrophs, and somatotrophs is influenced by different in vivo ovarian hormonal conditions. Anterior lobes of the pituitary gland were harvested from ovariectomized and ovarian steroid-replaced adult female rats 10-12 d after surgery. Quantitative immunocytochemistry was performed on enzymatically dispersed pituitary cells. The presence of ET-1-like immunoreactivity in prolactin-, luteinizing hormone-, or growth hormone-producing cells was demonstrated by double-label immunocytochemistry. The incidence of ET-1 immunopositive pituitary cells was unaffected by progesterone treatment alone. Estradiol replacement caused a modest decrease in the number of lactotrophs and somatotrophs expressing ET-1 but increased the incidence of ET-1 immunopositive cells among gonadotrophs. Combined treatment with estradiol and progesterone robustly increased the incidence of ET-1 immunopositive lactotrophs and gonadotrophs but had no effect on somatotrophs. These data reveal that the synthesis of ET-1-like peptides in lactotrophs and gonadotrophs (and, to a lesser extent, in somatotrophs) is sensitive to ovarian steroids. Furthermore, these findings predict that ovarian steroids modulate ET-1 biosynthesis during the estrous cycle, suggesting a possible mechanism by which the ovarian steroid milieu may regulate the responsiveness of lactotrophs and gonadotrophs to their hypothalamic secretagogues.
B Kanyicska; A Lerant; M E Freeman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Endocrine     Volume:  14     ISSN:  1355-008X     ISO Abbreviation:  Endocrine     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-06-07     Completed Date:  2001-10-11     Revised Date:  2010-06-24    
Medline Journal Info:
Nlm Unique ID:  9434444     Medline TA:  Endocrine     Country:  United States    
Other Details:
Languages:  eng     Pagination:  263-8     Citation Subset:  IM    
Department of Biological Science, Florida State University, Tallahassee 32306-4340, USA.
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MeSH Terms
Drug Implants
Endothelin-1 / analysis*
Estradiol / administration & dosage,  pharmacology*
Fluorescent Antibody Technique
Follicle Stimulating Hormone / analysis
Growth Hormone / analysis*
Luteinizing Hormone / analysis
Pituitary Gland, Anterior / chemistry*,  drug effects,  metabolism
Progesterone / administration & dosage,  pharmacology*
Prolactin / analysis*
Rats, Sprague-Dawley
Grant Support
Reg. No./Substance:
0/Drug Implants; 0/Endothelin-1; 50-28-2/Estradiol; 57-83-0/Progesterone; 9002-62-4/Prolactin; 9002-67-9/Luteinizing Hormone; 9002-68-0/Follicle Stimulating Hormone; 9002-72-6/Growth Hormone

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