Table of Contents

  2.1.3. Prolactinoma and Pregnancy        2.3. Enhanced Stimulation of the Prolactin Secretion in the Central Nervous System

2.2. Hyperprolactinemia in the Event of Reduced Inhibitive Prolactin Activity from the Central Nervous System (Hypothalamus)

Non-hormone-releasing and other pituitary-hormone-secretory hypophysis tumours can result in a hyperprolactinemia (pseudoprolactinoma, attendant hyperprolactinemia). It is of clinical importance to differentiate by diagnosis between a macroprolactinoma and a pseudoprolactinoma, as the latter would not respond to medication therapy with ensuing shrinkage of the tumour (see below). In the case of attendant hyperprolactinemia, the prolactin levels are frequently inadequately low given the size of the tumour. However, cystic, i.e. hollowed-out macroprolactinoma, which can simulate a large adenoma volume in an x-ray, occasionally ensue in lower prolactin levels. A precise diagnosis can only be obtained by means of a tissue examination (immune histology).

Tumours claiming suprasellar space, craniopharyngioma and other hypothalamic tumours ensue in the destruction of the dopamine-forming centres in the hypothalamus, and thereby in disinhibition of the prolactin cells with consequent hyperprolactinemia.

As these patients frequently also suffer from the lack of other stimulating hypothalamic neurohormones, they then also show an insufficiency of anterior pituitary hormones or enhanced water exudation (diabetes insipidus).

Processes at the cranial base, for example chronic inflammatory diseases (granu-lomatoses) or malignant system diseases, such as Hodgkin's disease can derange the transport of dopamine to the prolactin cells of the anterior pituitary lobe, thus inducing hyperprolactinemia (see Table 3).

One of the most frequent causes for hyperprolactinemia is the administration of medication interfering with the dopamine metabolism. As a rule, these are dopamine- antagonistic substances, which compete with the dopamine for the receptors at the prolactin cells. This refers in particular to medication suppressing nausea, such as Metoclopramide and psycho-active drugs, such as Sulpiride or phenothiazines, as well as neuroleptic drugs, in particular Haloperidol (Table 5).

ClassificationType of substance
Neuroleptic drugs, antidepressants,
tranquilisers psychoactive drugs)
Phenothiazines, thioxanthenes,
butyrophenones (Haloperidol,
Pimozide), benzamides (Sulpiride),
amitriptyline, imipramine
Anti-emetics (against nausea)Benzamides (Metoclopramide,
Domperidone), phenothiazines
Drugs against high blood pressureReserpine, alpha-methyl dopa
HormonesEstrogens, TRH
AntihistaminesCimetidin, Meclizine, Tripeleneamine

Tab. 5: Medication Leading to Hyperprolactinemia

  2.1.3. Prolactinoma and Pregnancy        2.3. Enhanced Stimulation of the Prolactin Secretion in the Central Nervous System

Gerhard Leyendecker