In vitro release of ACTH from dispersed rat pars intermedia cells. I. Effect of secretagogues.
Studies were made to test the responsiveness of dispersed pars intermedia (PI) cells to a number of secretagogues, that are known to alter ACTH release from the pars distalis (PD) in vitro. In summary, (a) incubation in high (K+), which will increase ACTH release from the PD, did not alter ACTH release from the PI; (b) a crude extract of rat hypothalamus (HE) increased ACTH release from PD and PI; (c) the effect of HE was not due to its vasopression content, since pretreatment of the extract with thioglycolic acid did not modify its ACTH-releasing activity and neither lysine nor arginine vasopressin stimulated ACTH release from the PI; and (d) a partially purified CRF preparation, which will stimulate ACTH release from the PD, did not alter ACTH release from the PI. We conclude that the hypothalamus contains a substance(s) that will stimulate ACTH release from the PI and that the 'secretagogue' is neither vasopressin nor the same CRF that will stimulate ACTH release from the PD.
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D007031:Hypothalamus; D008297:Male; D010902:Pituitary Gland / Q000378:metabolism*; D011188:Potassium; D051381:Rats; D013268:Stimulation, Chemical; D013806:Theophylline / Q000494:pharmacology; D013864:Thioglycolates / Q000494:pharmacology; D014020:Tissue Extracts / Q000494:pharmacology*; D014667:Vasopressins
D013864:Thioglycolates; D014020:Tissue Extracts; D014667:Vasopressins; D000324:Adrenocorticotropic Hormone; D013806:Theophylline; D011188:Potassium