Increased Luteinizing Hormone Sensitivity to Dopamine Inhibition in Polycystic Ovary Syndrome*

Abstract

The elevated LH secretion in 8 patients with the polycystic ovarian syndrome (PCO) was promptly suppressed by the infusion of dopamine (DA; 4 microgram/kg.min for 4 h). Compared to normal women studied during the early follicular phase, the maximal LH suppression due to DA infusion was significantly greater in PCO patients when expressed as either the net or percent decrease. This enhanced LH sensitivity to DA inhibition in PCO patients with chronically elevated estrogens, suggests that the inappropriately elevated LH release and the exaggerated LH pulses may be causally related, in part, to a reduction of endogenous DA inhibition of LH secretory activity.

Endocrinological and histological aspects of the process of polycystic ovary formation in the rat treated with testosterone propionate.

“…Endocrinological features of polycystic ovary (PCO) syndrome are characterized by high levels of serum LH and testosterone, high estrone to estradiol ratios (Raj aniemi et al 1980; Quigley et al 1981), and by excessive response of the serum LH level to LH-RH stimulation (Duignan 1976;Ota et al 1979). About thirty percent of the patients are associated with hyperprolactinemia (Thorner 1977;Ota et al 1979; Alger et al 1980;Wortsman and Hirschowitz 1980).…”

Formation of polycystic ovary in mature rats by the long-term administration of human chorionic gonadotropin.

“…That is, a drip infusion of dopamine hydrochloride typically inhibits LH secretion (Quigley et al 1981), suggesting the decreased control of dopamine on LH. Also, a single injection of metoclopramide, a dopamine receptor antagonist (Vazquez-Matute et al 1979), raised the prolactin level over the normal level in the women with regular menstrual cycles (Alger et al 1980).…”

Modulation of ovarian LH receptor and serum hormone levels in rats with hyperprolactinemia induced by administration of ovine prolactin or sulpiride.

“…LH secretion is stimulated by LH-RH, which is secreted from the hypothalamus and is considered to be regulated in part by dopamine (Quigley et al 1981). This elevation in serum LH appears to be an abnormal phenomenon and may be resulted in by disturbance in dopamine turnover by high levels of prolactin (Judd et al 1979 ;Alger et al 1980).…”