In vitro prolactin release from pituitaries of ovariectomized, estradiol-treated Holtzman rats: a direct comparison of dispersed cells and tissue explants.
In this study we compared prolactin (PRL) release from pituitary explants with that from dispersed cells from two regions of anterior pituitaries obtained from ovariectomized rats treated for 7 days with estradiol. Pituitaries were cut horizontally into dorsal (or inner) and ventral (or outer) zones. One half of each these regions was enzymatically dispersed to cells; the other half was bisected and examined as tissue explants. The dispersed cells and explants were perifused in parallel over a 2 hour period with dopamine (1 microM) present for the first hour and absent during the second hour. Prolactin released into the perifusion medium was measured by radioimmunoassay. Tissue explants secreted more total prolactin than did cells in the presence or absence of dopamine and the pattern of release was sustained compared to the more transient release observed in dispersed cells. However, the response to dopamine withdrawal was not different between cells and explants when expressed as a percent change from respective controls. The results suggest that organization and architecture of the rat anterior pituitary may be important factors for overall prolactin production, but in terms of relative responsiveness to dopamine and its withdrawal, dispersed cells and tissue explants appear equivalent.
Hu
L
L
Department of Physiology, Wayne State University of Medicine, Detroit, MI, USA.
Lawson
D M
DM
D000818:Animals; D046508:Culture Techniques; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007124:Immunoenzyme Techniques; D010052:Ovariectomy; D010902:Pituitary Gland / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D004958:Estradiol; D011388:Prolactin