ANTIANDROGENIC EFFECTS OF THE PINEAL GLAND AND MELATONIN IN CASTRATED AND INTACT PREPUBERTAL MALE RATS

in Journal of Endocrinology
Authors:
R. ALONSO
Search for other papers by R. ALONSO in
Current site
Google Scholar
PubMed
Close
,
L. PRIETO
Search for other papers by L. PRIETO in
Current site
Google Scholar
PubMed
Close
,
C. HERNANDEZ
Search for other papers by C. HERNANDEZ in
Current site
Google Scholar
PubMed
Close
, and
M. MAS
Search for other papers by M. MAS in
Current site
Google Scholar
PubMed
Close
Restricted access
Rent on DeepDyve

Sign up for journal news

In castrated prepubertal rats, pinealectomy enhanced the testosterone-induced growth response of the seminal vesicles and melatonin inhibited this effect in a dose-related manner. In entire animals, the serum concentration of LH was increased after pinealectomy with no significant changes in other parameters. Administration of melatonin to intact, pinealectomized rats did not affect the serum concentrations of LH or testosterone but caused a doserelated decrease in the weight of the seminal vesicles. The highest dose of melatonin tested reduced the weight of the ventral prostate gland and the uptake of radioactivity by both the ventral prostate gland and the testes after injection of [5-3H]uridine. It is suggested that the pineal gland and melatonin may exert an antagonistic effect on the biological activity of androgens administered to castrated rats and that melatonin can reduce the growth of the accessory sex organs of intact, pinealectomized rats, in spite of a high concentration of LH in the serum. The well-known inhibitory influence of systemically administered melatonin on the accessory sex organs in male rats may be due to its antagonistic effect at a peripheral level.

 

  • Collapse
  • Expand