REGULATORY EFFECTS OF ESTROGENS ON THE PITUITARY CONTENT OF SECRETOGRANIN-II AND CHROMOGRANIN-A

Modulation of pituitary content of secretogranin II and chromogranin A has been compared to that of luteinizing hormone (LH) in adult female rats following gonadectomy and subsequent estradiol therapy. Both proteins were quantified using two specific antisera, BS 487 and anti-CAP-14, respectively. Ovariectomy promoted an increase in the concentration of secretogranin II and chromogranin A, though to a lesser degree than that of LH. Moreover, intracellular processing of secretogranin II was significantly enhanced. Daily estradiol injection further increased pituitary secretogranin II and LH contents while that of chromogranin A was reduced to sham-operated control values. These data 1) demonstrate that both granins are differentially regulated through ovarian factors, and 2) confirm that regulation of secretogranin II production may be closely related to that of LH.