Return of Gonadal Function in Men with Prolactin-Secreting Pituitary Tumors*

Abstract

Gonadal function was evaluated in 10 men [33 +/- 17 (SD) yr] with pituitary tumors and hyperprolactinemia (47-2550 ng/ml) using nocturnal penile tumescence (NPT), semen analysis, urinary LH and FSH excretion, and diurnal variation of serum testosterone and PRL. Results were compared to 16 normal subjects (33 +/- 13 yr). NPT was decreased in tumor patients as demonstrated by reduced maximum circumference change (P less than 0.01) and total tumescence time (P less than 0.05). Semen analysis was examined in 5 patients able to produce specimens. All seminal parameters were significantly abnormal as demonstrated by oligospermia, asthenospermia, teratospermia , and elevated fructose. Urinary LH [570 +/- 72 (SE) vs. 838 +/- 22 mIU/h; P less than 0.01] and serum testosterone (235 +/- 60 vs. 625 +/- 63 ng/dl; P less than 0.01) were decreased in 9 tumor patients, all of whom had serum PRL levels above 50 ng/ml. Diurnal variation of serum PRL was absent in hyperprolactinemic patients whereas all had normal circadian changes in serum testosterone, although at a lower set point. Eight patients were followed for 6-13 months after reduction of serum PRL by surgery and/or drug therapy. Serum PRL reached normal levels in six men after 6 months of treatment. Selected individuals had an increase in serum LH after 2 months of treatment. Significant rises in serum testosterone occurred as early as 3 months and normal levels were found in six patients after 6-8 months of treatment. Only two subjects, however, demonstrated a normal semen analysis. These data suggest that men with serum PRL levels above 50 ng/ml maintain a normal diurnal pattern of serum testosterone at a lower set point, and demonstrate hypogonadism with reduced urinary LH excretion and NPT. In addition, routine seminal parameters are clearly abnormal and are both delayed and incomplete in their recovery.

Successful gonadotrophin treatment of hypogonadism in postoperative patients with macroprolactinoma and persistent hyperprolactinaemia

“…However, improvement of hypogonadism is often insufficient even after these treatment regimens. Although successful transsphenoidal extirpation of prolactin-secreting tumours has been reported (Pont et al, 1979), many of the procedures resulted in inadequate control of hyperprolactinaemia, leaving hypogonadism and impotence unchanged (Carter et al, 1978;Franks et al, 1978). Spontaneous recovery of testicular function after treatment does not occur in cases of prolactinoma with persistent postoperative hyperprolactinaemia.…”

“…hyperprolactinaemia per se causes testicular dysfunction leading to hypogonadism Faglia et al, 1977). Recovery of testicular function occurs after transsphenoidal surgery of the macroadenomas, with or without oral administration of dopaminergic agonists or bromocriptine (Arafah et al, 1981;Murray et al, 1984). It has been reported that recovery of testicular function takes place only several months after serum prolactin levels are normalized (Arafah et al, 1981).…”

“…Patients with hyperprolactinaemia with macroadenoma impotence and infertility are usually prominent symptoms. of the pituitary gland usually present with hypogonadism However, the aetiology of hypogonadism under such (Koizumi et al, 1984;Murray et al, 1984). In men, circumstances remains obscure.…”

Intrapituitary mechanisms underlying the control of fertility: key players in seasonal breeding

“…In humans, hypersecretion of prolactin resulting from a pituitary prolactinoma is a major cause of amenorrhea in women and impairs fertility in men [35], [36], but the specific mechanisms underlying these inhibitory effects on fertility remain unresolved. In sheep, administration of thyrotropin-releasing hormone (TRH), a potent stimulator of prolactin secretion, disrupted the estradiol-induced preovulatory surge of LH [37].…”

Effects of Chronic Hyperprolactinemia on Sexual Arousal and Erectile Function in Male Rats

“…For example, several studies have suggested that libido is primarily affected, and that impo tence associated with hyperPRL occurs secondarily to de creased sexual desire [5,35]. In another recent study, noc turnal penile tumescence was reduced in hyperprolactin emic men both in terms of reduced maximum circumfer-ence change and decreased tumescence time, an indication of organic impotence [29], Thus, despite the fact that sexual dysfunction associated with hyperPRL in men is readily treatable [22], very little is known about the mechanisms b\ which hyperPRL affects libido and potency, and to what degree the accompanying hypogonadism may contribute to these effects [14,31].…”