Clinical and Hormonal Response To Bromocriptin (CB-154) in the Galactorrhea Syndromes

Abstract

Nine female patients with galactorrhea were selected for treatment with Bromocriptin® (CB-154), a specific inhibitor of prolactin secretion. Elevated plasma prolactin (hPRL) was found in 7 of these cases, whereas 2 exhibited values within normal limits. LHRH (100 fig) stimulation elicited plasma LH/FSH increases in 6 of the women who were amenorrheic prior to therapy, indicating a suprasellar cause for the patients' failure to cycle. After TRH (250 fig) stimulation, 5 women out of 6 exhibited a blunted hPRL response and 4 of them failed to show any elevations after administration of chlorpromazine. It was only in one patient who exhibited basal hPRL within the normal range, that an average response to TRH was elicited. The possible mechanisms explaining the low levels of pituitary stimulation obtained are discussed.Treatment with CB-154 (3-5 mg/day) induced a fall in serum hPRL accompanied by cessation of milk secretion in 8 patients. Menses were restored in 7 amenorrheic women and corpora lutea formation was confirmed by elevated plasma progesterone levels in 6 of them. One patient exhibiting normal serum hPRL and amenorrhea following the discontinuation of an oral contraceptive failed to resume menses under CB-154 therapy despite a fall in hPRL, suggesting that the mechanisms involved were not prolactin-dependent.Hyperprolactinemia and galactorrhea tended to recur when therapy was withheld, indicating to a certain extent persistent autonomy of the mechanisms involved. Since CB-154 has been found to inhibit not only prolactin secretion but also hormone synthesis, it remains to be seen whether long-term therapy with this agent may induce permanent remissions in patients with galactorrheaamenorrhea. (/ Clin Endocrinol Metab 39: 18, 1974)

Does Bromocriptine Block Thyrotropin-Releasing Hormone-Induced Prolactin Release during Pregnancy?*

“…This is in keeping with the report of normal pregnancies in women with defective PRL secretion (15), although the existence of isolated PRL deficiency has been questioned in the last few years. Bromocriptine at 5 mg daily blocked the PRL responses to TRH in healthy women (3). This was confirmed in our volunteers when studied in the presence of bromocriptine during the postabortal state.…”

“…B ROMOCRIPTINE inhibits PRL synthesis in both healthy subjects and patients with PRL-secreting tumors (1)(2)(3)(4). On the other hand, TRH is known to release PRL from the pituitary in nonpregnant (5,6) and pregnant women (7,8).…”

Effect of Prolactin on LH Release in Male Rats

“…However, some results of the literature might provide indirect evidence for a prevalent hypothalamic site of action of Prl. The responsive ness of gonadotropins to LH-RH is well maintained in hyperprolactinemic women [Aono et al, 1976;D el [L eo n a rd elli, 1976], Unfortu nately, a conclusion cannot be reached because conflicting evidence has also been presented. In lactating rats submitted to a strong Prl-releasing stimulus, or injected with exogenous Prl, the LH-RH responses have been reported to be low or absent [Lu et al, 1976; M u r a l id h a r e t al.…”

Prolactin secretion in infertile men before and after treatment with bromocriptine

“…This rye ergot alkaloid inhibits the secretion of prolactin (Del Pozo et al, 1972), and its use in cases of hyperprolactinemia provokes the reappearance of the menstrual cycle in most cases (Besser et al, 1972 ;Del Pozo et al, 1974 ;Seki, Seki and Okumura, 1975 ;Fossati, Strauch and Tourniaire, 1976). Bromocriptine does not modify LH or FSH, but increases estradiol secretion (Seppala et al, 1976 …”