Variations in prolactin secretion in hyper- and normoprolactinaemia with or without galactorrhoea.

The circadian variations and secretory rhythms in prolactin secretion were examined in 10 hyperprolactinaemic and 10 normoprolactinaemic women with or without galactorrhoea in order to establish a clearer picture of this secretion and to find, if exists, correlation between the prolactin level and galactorrhoea. In the normoprolactinaemic women a rhythmical rise and fall were observed within 20 min, with higher values during nocturnal sleeping; these changes were more marked in the galactorrhoeic group. In the hyperprolactinaemic group the diurnal and pulsation changes were less pronounced, galatorrhoea usually being accompanied by a higher degree of hyperprolactinaemia. In galactorrhoeic patients with a normal basal prolactin level, a relative prolactin excess may be reckoned with at certain times. A proportion of these women can in fact then be regarded as hyperprolactinaemic. In the hyperprolactinaemic cases without galactorrhoea, a decreased prolactin sensitivity and milk-forming ability of the breasts may be assumed.