In vitro immunoneutralization of a cleaved prolactin variant: evidence for a local paracrine action of cleaved prolactin in the development of gonadotrophs and thyrotrophs in rat pituitary.
We have previously isolated a cleaved prolactin variant, secreted by rat pituitary cells in culture, that stimulated [3H]thymidine incorporation into DNA in gonadotrophs and thyrotrophs when added to pituitary aggregate cell cultures of 14-day-old female rats. Using synthetic peptides homologous to the new C- and N-termini of the cleavage site, we made antisera recognizing this cleaved variant without significant cross reaction with native prolactin. Addition of these antisera to pituitary aggregate cell cultures decreased [3H]thymidine incorporation into DNA in gonadotrophs and thyrotrophs but not in the other pituitary cell types. These data are further evidence that this prolactin variant, cleaved between Tyr-145 and Leu-146, may have an important role as growth regulator of the gonadotrophs and thyrotrophs in the rat pituitary.
Andries
M
M
Department of Molecular Cell Biology, Katholieke Universiteit Leuven, Belgium.
Jacobs
G F
GF
Tilemans
D
D
Denef
C
C
D000818:Animals; D000906:Antibodies / Q000032:analysis / Q000276:immunology; D000918:Antibody Specificity; D001345:Autoradiography; D002478:Cells, Cultured; D005260:Female; D006062:Gonadotropins / Q000096:biosynthesis*; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D010902:Pituitary Gland / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D011388:Prolactin / Q000276:immunology* / Q000502:physiology; D051381:Rats; D013936:Thymidine / Q000378:metabolism; D013972:Thyrotropin / Q000096:biosynthesis*
D000906:Antibodies; D006062:Gonadotropins; D011388:Prolactin; D013972:Thyrotropin; D013936:Thymidine