The Response of Creatine Kinase Specific Activity in Rat Pituitary to Estrogenic Compounds and Vitamin D Less-Calcemic Analogs

We examined the response of rat female pituitary at different metabolic stages to treatments with estrogenic compounds and vitamin D analogs. Immature or ovariectomized (Ovx) female rats responded by increased creatine kinase specific activity (CK) to estradiol-17 β (E 2 ), genistein (G), daidzein (D), biochainin A (BA), quecertin (Qu), carboxy- G (cG), carboxy- BA (cBA), and raloxifene (Ral). The response was inhibited when Ral was injected together with the estrogens. CK was increased when hormones were injected daily into Ovx rats for 4 different time periods. Pretreatment with the less-calcemic vitamin D analogs JK 1624 F 2 -2 (JKF) or QW 1624 F 2 -2 (QW) followed by estrogenic injection resulted in increased response and sensitivity to E 2 and loss of inhibition of E 2 by Ral. CK was also increased by feeding with E 2 or licorice or its components dose- and time- dependent in immature or Ovxrats. Diabetic female rats did not respond to increased doses of E 2 . In conclusion, rat female pituitary is estrogens-responsive organ, suggesting to considerits response for HRT in postmenopausal women for both beneficial and hazardous aspects.