Hyperprolactinemic disorders

Mild hyperprolactinemia in a couple: what impact on fertility?

Mild-to-moderate hyperprolactinemia is a frequent finding in young women presenting with infertility. Prolactin (PRL) concentration should be determined accurately, whether or not the patient has other symptoms suggestive of excess PRL such as galactorrhea or menstrual cycle disorder. After confirmation of persistent hyperprolactinemia on a second blood sample (avoiding conditions known to raise prolactin) and exclusion of macroprolactinemia, prolactinoma and other identifiable non-tumoral causes of hyperprolactinemia must be ruled out. Mildly elevated PRL levels may cause luteal insufficiency in cycling women and are associated with recurrent miscarriage. Any confirmed hyperprolactinemia should be treated in a woman who wishes or fails to become pregnant. Preference is given to cabergoline at the lowest possible dose that normalizes PRL, restoring fertility in the vast majority of cases. Evidence is much less robust in men, in whom PRL concentrations are less prone to increase and the reproductive system is less sensitive to the negative effects of hyperprolactinemia. Nevertheless, chronic and significant hyperprolactinemia in men may impair fertility or cause infertility (with or without hypogonadism) and must be treated, as in women. However, more clinical studies are clearly needed concerning male reproductive function. The significance of mild but persistent hyperprolactinemia in either member of a couple incidentally discovered during assisted reproductive technology (ART) procedures is unclear, and future evidence-based studies are needed to determine whether normalizing prolactin can improve ART outcome.

The risks of overlooking the diagnosis of secreting pituitary adenomas

Secreting pituitary adenomas that cause acromegaly and Cushing’s disease, as well as prolactinomas and thyrotroph adenomas, are uncommon, usually benign, slow-growing tumours. The rarity of these conditions means that their diagnosis is not familiar to most non-specialist physicians. Consequently, pituitary adenomas may be overlooked and remain untreated, and affected individuals may develop serious comorbidities that reduce their quality of life and life expectancy. Because many signs and symptoms of pituitary adenomas overlap with those of other, more common disorders, general practitioners and non-endocrinology specialists need to be aware of the “red flags” suggestive of these conditions. A long duration of active disease in patients with secreting pituitary adenomas is associated with an increased risk of comorbidities and reduced quality of life. Appropriate treatment can lead to disease remission, and, although some symptoms may persist in some patients, treatment usually reduces the incidence and severity of comorbidities and improves quality of life. Therefore, correct, early diagnosis and characterization of a pituitary adenoma is crucial for patients, to trigger timely, appropriate treatment and to optimize outcome. This article provides an overview of the epidemiology of hormonal syndromes associated with pituitary adenomas, discusses the difficulties of and considerations for their diagnosis, and reviews the comorbidities that may develop, but can be prevented, by accurate diagnosis and appropriate treatment. We hope this review will help general practitioners and non-endocrinology specialists to suspect secreting pituitary adenomas and refer patients to an endocrinologist for confirmation of the diagnosis and treatment.

Prolactinoma in pregnancy

Prolactinomas commonly cause infertility and treatment usually restores ovulation and fertility. The dopamine agonists are the preferred mode of treatment, with cabergoline generally being preferred to bromocriptine because of its higher therapeutic ratio. Experience with both drugs shows no increase in spontaneous abortions, preterm deliveries, multiple births, or congenital malformations, compared to what is expected in the normal population but the experience with bromocriptine is approximately 10-fold greater than with cabergoline. Clinically significant tumor growth may occur in 2.7% of those with microadenomas, 22.9% in those with macroadenomas without prior ablative treatment and 4.8% of those with macroadenomas with prior ablative treatment. Patients with macroadenomas should have visual fields assessed periodically during gestation. Should symptomatic tumor growth occur, reinstitution of the dopamine agonist is usually successful in shrinking the tumor but delivery if the pregnancy is sufficiently advanced is also an option and transsphenoidal debulking is rarely necessary.

The brain Renin-Angiotensin system and the regulation of prolactin secretion in female rats: influence of ovarian hormones

Abstract This study was designed to investigate the effects of exogenous and endogenous angiotensin II (All) on prolactin release in ovariectomized rats, with and without estrogen and progesterone pretreatment. In the first series of experiments, All or vehicle was injected into the third cerebral ventricle of conscious, freely-moving rats. In both treated and untreated rats, administration of 50 ng All suppressed prolactin levels within 15min of injection, compared to vehicle-injected rats. In untreated rats, prolactin levels returned to baseline values by 30 min, while in treated rats, prolactin levels remained suppressed for an hour. In the second series of experiments, the involvement of endogenous brain All in tonically suppressing prolactin release was assessed by administering either All receptor blockers (saralasin or sarthran) or an All synthesis inhibitor (enalaprilat, an inhibitor of the conversion of angiotensin I to All). Neither All receptor blockade nor converting enzyme inhibition resulted in any change in prolactin levels in untreated levels in untreated rats. However, following treatment with ovarian steroids, infusion of saralasin or injection of enalaprilat resulted in a significant increase in plasma prolactin tilers. During saralasin infusion, prolactin levels were significantly increased by 15 min and continued to be higher than controls at 60 min. After enalaprilat administration, prolactin levels did not rise significantly until 90 min and then remained elevated up to 120 min post-injection. These latter results suggest that at least one h is required for maximal inhibition of angiotensin synthesis in the brain. These data demonstrate that low doses of All suppressed basal prolactin secretion in both untreated and ovarian steroid-treated, ovariectomized rats. However, treated rats appeared to be more sensitive than untreated animals to the prolactin-lowering effects of centrally administered All. The lack of prolactin response in untreated rats when brain All synthesis was inhibited or All receptors were blocked suggests that, in the absence of ovarian steroids, endogenous All was not acting tonically to suppress prolactin secretion. Following exposure to ovarian steroids, however, the endogenous brain All system appeared to be activated and involved in controlling prolactin release.