Since the early seventies, chronic hyperPRLaemia due to hypothalamic-pituitary
disorders, drug abuse, hypothyroidism or other causes, has been recognized as a cause
of reproductive dysfunctions in both women and men. Possible mechanisms by which
PRL exerts its effects on male reproductive functions have been extensively studied
during the last two decades, but the mode of PRL action on reproductive functions has
not been clarified by these studies.
Mter an introduction on the physiological significance of PRL in vertebrates and
the possible molecular processes involved in PRL action (chapter I), experimental
models are discussed to study the effects of hyperPRLaernia on male reproductive
functions in the rat (chapter II). This animal was used in the experiments presented in
this thesis, because of the resemblance between the effects of hyperPRLaernia observed
in rats and humans. During the experiments, the transplantable PRL-secreting tumour
7315b was employed as an experimental model to induce high serum PRL levels (2000-
5000 ng/rnl), comparable to those found in humans with hyperPRLaernia-associated
impotence.
Preceding the presentation of the data obtained from the experiments discussed
in this thesis (chapters IV, V, VI, VII and VIII), male reproductive dysfunctions during
hyperPRLaernia in the rat are reviewed (chapter III). Subsequently, aims and questions
which are dealt with in this thesis are described