Pub. Date : 1999 Dec
PMID : 10601975
6 Functional Relationships(s)Download |
Sentence | Compound Name | Protein Name | Organism |
| 1 | A novel mechanism for the melatonin inhibition of testosterone secretion by rat Leydig cells: reduction of GnRH-induced increase in cytosolic Ca2+. | Testosterone | gonadotropin releasing hormone 1 | Rattus norvegicus |
| 2 | The site of inhibition, by melatonin, of GnRH-dependent testosterone secretion was investigated in adult rat Leydig cells cultured in vitro. | Testosterone | gonadotropin releasing hormone 1 | Rattus norvegicus |
| 3 | Testosterone secretion was then evaluated after 3 h stimulation with GnRH, thapsigargin (1 microM), phorbol-12-myristate-13-acetate (100 nM), arachidonic acid (20 microM), and ionomycin (1 microM) in the presence or absence of melatonin (215 nM). | Testosterone | gonadotropin releasing hormone 1 | Rattus norvegicus |
| 4 | Melatonin attenuated the increase in [Ca(2+)](i) and inhibited the testosterone secretion induced by GnRH, but not that induced by ionomycin. | Testosterone | gonadotropin releasing hormone 1 | Rattus norvegicus |
| 5 | Both ionomycin and thapsigargin potentiated GnRH-induced testosterone secretion; however, ionomycin, but not thapsigargin, partially prevented the inhibitory effect of melatonin on cells stimulated with GnRH. | Testosterone | gonadotropin releasing hormone 1 | Rattus norvegicus |
| 6 | We conclude that melatonin reduces GnRH-induced testosterone secretion by 1) decreasing [Ca(2+)](i), through impairment of the GnRH-dependent release of Ca(2+) from intracellular stores and 2) blocking 17-20 desmolase enzymatic activity, an effect that occurs irrespective of changes in [Ca(2+)](i). | Testosterone | gonadotropin releasing hormone 1 | Rattus norvegicus |