title: Nongenomic actions of testosterone on a subset of lactotrophs in the male rat pituitary.
abstract: Rapid, nongenomic effects of testosterone on PRL release in vitro were investigated. Anterior pituitary tissue from adult male rats was stimulated in vitro for 5 or 20 min with testosterone (T; 1 or 100 nM) or testosterone-BSA (T-BSA; 1 or 100 nM) with or without 1.2 mM tannic acid, which enables visualization of secretory granule exocytosis. Within 5 min, both concentrations of T and T-BSA stimulated exocytosis from type 2 lactotrophs (characterized by small spherical granules), but not from type 1 lactotrophs (characterized by large polymorphic granules). The effects of T on type 2 lactotrophs could be blocked by preincubation with dopamine (500 nM), but were not time or concentration dependent, and could not be inhibited by 1) removal of extracellular Ca2+, 2) the L-type Ca2+ channel blocker nifedipine (100 nM), 3) the Ca2+-adenosine triphosphatase inhibitor thapsigargin (150 nM), 4) the PKC inhibitor retinal (10 microM), or 5) the gamma-aminobutyric acidA chloride channel blocker picrotoxin (100 microM). T-BSA (0.1 nM to 1 microM) for 5 or 20 min also caused an increased release of immunoreactive PRL into the medium compared with control incubations. T and T-BSA did not stimulate exocytosis from gonadotrophs or cause LH release. In conclusion, we report for the first time a rapid, nongenomic effect of T on PRL secretion.
authors.affiliation: Department of Human Anatomy and Genetics, University of Oxford, United Kingdom.
authors.forename: H C
authors.initials: HC
authors.lastname: Christian
authors.forename: N J
authors.initials: NJ
authors.lastname: Rolls
authors.forename: J F
authors.initials: JF
authors.lastname: Morris
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects; D005404:Fixatives; D047348:Hydrolyzable Tannins; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D008854:Microscopy, Electron; D010902:Pituitary Gland / Q000166:cytology* / Q000187:drug effects / Q000648:ultrastructure; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D011388:Prolactin / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013739:Testosterone / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D005404:Fixatives; D047348:Hydrolyzable Tannins; D012710:Serum Albumin, Bovine; D013739:Testosterone; D011388:Prolactin; D007986:Luteinizing Hormone; D011493:Protein Kinase C; D000252:Calcium-Transporting ATPases; D002118:Calcium