Interaction of dopaminergic and antiserotoninergic drugs in the control of prolactin and LH release in normal women

Abstract

Prolactin (Prl) release, both in the experimental animal and in man, is stimulated by serotonin (5HT) and inhibited by dopamine (DA). Data also suggest that LH release in the animal is stimulated by norepinephrine and inhibited by DA. The role of 5HT in the control of LH release is less clear. It would appear to stimulate episodic LH release and to inhibit the LH surge at the pro-oestrus in animals, but the effect of 5HT on LH release has not yet been evaluated in man. In the present paper we have studied the effect of various DA-ergic drugs (DA, iv 1-dopa, po 1-dopa and bromoergocriptine) and of two anti-5HT drugs, metergoline and methysergide, on Prl and LH release in normal women. DA-ergic drugs lowered plasma Prl and LH levels; anti-5HT drugs, at doses able to lower Prl levels, did not affect basal LH release nor the inhibiting effect of iv 1-dopa on LH release. These data indicate that DA inhibits both LH and Prl release in normal women, and that 5HT stimulates Prl release but is not involved in the regulation of LH secretion. The fact that, at variance to all the DA\x=req-\ ergic drugs used, the two anti-5HT drugs did not vary LH release, suggests that metergoline and methysergide are devoid of DA-ergic activity in man, at least at the doses able to inhibit Prl release.

Metergoline in the Management of Hyperprolactinemic Amenorrhea and Anovulation

“…Serotonin is known to inhibit LH release in the rat [18,19]; this fact, together with the fact that in our patients LH levels increased even in the presence of an elevated PRL level, would indicate that metergoline en hances, when administered repeatedly, LH release; this hypothesis deserves further clarification since metergoline, administered acutely, is without effect on LH release [20], Whatever its mechanism of action, metergoline appeared to be a safe and effective drug able to lower serum PRL levels, to induce the return of menstrual cycles and fertility and to stop galactor rhea.…”

Treatment of hirsutism in polycystic ovary syndrome with bromocriptine

“…Studies on rats using various dopamine agonists and antagonists have given conflicting evidence. In normal women dopamine infusion has been shown to decrease LH secretion (Martin et al 1981;Judd et al 1978Judd et al , 1979Pontiroli 1980) and also suppress spontaneous LH pulses (Martin et al 1981). Similar LH inhibition follows L-dopa treatment (Lachelin et al 1977).…”

“…1954) and in hypogonadal women LH pulsatility was maintained despite dopamine receptor blockade (Nyboe Anderson & Tabor 1982). Acute administration of bromocriptine in normal women can reduce LH secretion (Pontiroli et al 1980) or have no effect (Martin et al 1981). However, brornocriptine therapy in hyperprolactinaemic women does not block physiological LH secretion since ovulation occurs readily after prolac-tin levels are reduced (Thorner et al 1974;Strauch et al 1977;Klibinski et al 1984).…”

Effect of Metergoline on Prolactin, Follicle Stimulating Hormone, Luteinizing Hormone and Thyroid Stimulating Hormone Response to TRH and LHRH in Normal Men and Women

“…Also another antiserotoninergic drug, methysergide maleate, did not affect the 24 hours secretory pattern of LH in women during the early follicular phase (Kapen, Vagenakis and Breverman 1980). In a direct comparison (Pontiroli et al 1980), dopamine, 1-dopa and bromocriptine lowered basal plasma levels of LH in normal females while metergoline and methysergide did not. Dopamine has been shown to inhibit LH secretion in men and women (Leblanc, Lachelin, AbuFadil and Yen 1976), even in the presence of constant GnRH infusion (Huseman, Kugler and Schneider 1980), and LH levels were lowered by the dopamine agonist pergolide mesylate (Perryman, Rogol, Kaiser, MacLeod and Thorner 1981).…”