In order to clarify the mechanism(s) which causes
galactorrhea and
amenorrhea in patients with
Galactorrhea-Amenorrhea Syndrome (GAS) (Group A, n = 20), composed of
Chiari-Frommel Syndrome (CFS) (Subgroup I, n = 3),
Argonz-del Castillo Syndrome (ADCS) (Subgroup II, n = 5) and
Drug-induced
Galactorrhea-
Amenorrhea (DIG) (Subgroup III, n = 12), we analysed basal plasma
prolactin (PRL) and
gonadotropin levels and their responsiveness to TRH and
LH-RH, respectively in GAS patients. In addition, another group of
galactorrhea patients without
amenorrhea (Group B, n = 29) was selected, and further divided into three subgroups; subgroup I (n = 7) with persisting postpartum lactation, subgroup II (n = 7) of idiopathic
galactorrhea, and subgroup III (n = 15) induced by
drug administration. There were found unexpectedly high frequencies of normoprolactinemic patients (less than 23.7 ng/ml) in 40% of GAS (66.7% in CFS, 40% in ADCS, and 33.3% in DIG). The PRL responsiveness to TRH, evaluated by % delta PRL (peak PRL - basal PRL/basal PRL X 100), tended to be high in ADCS and DIG (group after discontinuation of drugs) compared with those of normal subjects (n = 12) and patients with
primary hypothyroidism (n = 21). PRL response was almost normal in CFS or DIG (group during
drug administration). Basal level of plasma
gonadotropin in GAS was comparable to that of normal subjects. However, responsiveness of
gonadotropin to
LH-RH in GAS tended to be high compared with that of normal subjects. The patients in group B (subgroup I-III) demonstrated almost parallel responses of PRL and
gonadotropin, respectively, to those of corresponded subgroups in group A. From the present results, we concluded that; 1) It seems likely that frequency of normoprolactinemic patients in GAS (Group A) is surprisingly high. 2) A still unclarified mechanism(s) for the occurrence of
galactorrhea, not explained solely by plasma radioimmunoassayable PRL level and/or hyperresponsiveness of PRL to stimuli, may operate on a considerably large number of group A patients. 3) Decreased
gonadotropin secretion at pituitary level seems not to be a main cause of menstrual abnormality in group A patients. 4) The same mechanism(s) as in group A patients may cause
galactorrhea in group B patients.