Prolactin unresponsiveness and paradoxical elevation of estrogen despite gonadotropin suppression in postmenopausal women suffering from severe acute illness.

Introduction: Postmenopausal women constitute an ideal model for studying the extent of hypothalamo-pituitary-gonadal (HPG) axis suppression in critical illness as the gonadotropinsare normally high and non-cyclical in them. Objectives: The objective of this study is (i) to assess the impact of acute severe illness on the HPG axis in postmenopausal women, (ii) to correlate the severity of illness with (a) activity of the HPG axis, (b) the activity of the hypothalamo-pituitary-adrenal axis, (c) activity of the hypothalamo-pituitary-thyroid axis and (d) serum prolactin. Methods: A total of 35 postmenopausal women older than 60 years admitted to medical intensive care with a simplified acute physiology score II (SAPS II) more than 30, consistent with a predicted in-hospital mortality of greater than 10% were recruited. On day 5 of their hospital stay, blood samples were collected for estradiol, luteinizing hormone (LH), follicle stimulating hormone (FSH), cortisol, androstenedione and prolactin and thyroid profile. As controls, 35 apparently healthy postmenopausal women were recruited. Results: Levels of LH, FSH, free thyroxin (fT4) and triiodothyronine were lower while estradiol, cortisol and androstenedione were higher among patients in comparison with healthy controls. Prolactin levels were similar in patients and controls. Among sick patients both FSH and fT4 showed a negative correlation (P < 0.05) with the SAPS II score. Conclusions: Estrogens are paradoxically elevated despite gonadotropin suppression in critically ill postmenopausal women, suggesting a non-ovarian origin of the same. Prolactin remained unaltered despite illness in patients, possibly reflecting atrophy of lactotrophs in menopause. [ABSTRACT FROM AUTHOR]