Effects of pituitary hormones on the prostate.
BACKGROUND
Although essential, androgens alone are not sufficient to induce normal growth and functionality of the prostate. Nonandrogenic hormones must also be involved in the proliferation of the prostate cancer cells which do not respond to antiandrogenic therapy and which thus become androgen-independent. Prolactin, but also growth hormone and luteinizing hormone, are potentially able to act on both normal and abnormal prostatic cells.


METHODS
In this review we summarize data from the literature concerning the physiological and pathological implications of prolactin, growth hormone, and luteinizing hormone on the prostate.


RESULTS
In rodent prostates, prolactin and growth hormone can induce a variety of effects independently of androgens (e.g., transactivation of certain genes, or synthesis of the major secretion products). Moreover, hyperprolactinemia is responsible for inflammation and dysplasia of the gland, while growth hormone promotes the development of prostate tumors in vivo in the mouse and rat. Growth hormone acts on the gland directly, through prostatic growth hormone receptors, and/or indirectly via the stimulation of insulin-like growth factor-I (IGF-I) synthesis in the liver. Luteinizing hormone receptor is expressed in rat and human prostates. Luteinizing hormone increases the amount of various transcripts in the rat prostate through an androgen-independent pathway.


CONCLUSIONS
Prolactin, growth hormone, and luteinizing hormone, alone or synergistically with androgens, play physiologically significant roles in the normal prostate. The involvement of these hormones in the development of benign prostatic hyperplasia and prostatic carcinoma is an issue that needs to be addressed.
Reiter
E
E
Station de Physiologie de la Reproduction des Mammifères Domestiques, Institut National de la Recherche Agronomique, URA CNRS 1291, Nouzilly, France. reiter@tours.inra.fr
Hennuy
B
B
Bruyninx
M
M
Cornet
A
A
Klug
M
M
McNamara
M
M
Closset
J
J
Hennen
G
G
D000818:Animals; D013006:Growth Hormone / Q000502:physiology; D006801:Humans; D007986:Luteinizing Hormone / Q000502:physiology; D051379:Mice; D010902:Pituitary Gland / Q000502:physiology*; D010908:Pituitary Hormones, Anterior / Q000502:physiology*; D011388:Prolactin / Q000502:physiology; D051381:Rats