Gonadal steroids are potent modulators of gonadotropin releasing hormone (GnRH) secretion, and androgen binding sites and 5α-reductase activity have been found in the immortalized GnRH secreting cell line GT1-1, suggesting the existence of a direct androgenic control of GnRH dynamics. Two isoforms of the 5α-reductase have been cloned with very different biochemical/functional properties: 5α-reductase type 1 (widely distributed in the body) and 5α-reductase type 2 (confined in androgen target structures). We have analysed whether, in GT1-1, androgen binding sites are linked to 'classical' androgen receptor, and which 5α-reductase isoform is active. Reverse transcriptase-polymerase chain reaction analysis showed that the mRNAs coding for androgen receptor and for the two 5α-reductase isoforms are all expressed in GT1-1 cells. However, the 5α-reductase enzymatic reaction showed a peak of activity at a narrow pH around 5.5, the optimum for the 5α-reductase type 2. The affinity for testosterone, of the enzyme present in GT1-1 cells, was very similar to that observed for the recombinant type 2 isozyme expressed in yeasts. The data indicate that GT1-1 cells (i) express a 'classical' androgen receptor and (ii) contain the 5α-reductase type 2 isoform, a specific marker of androgen-responsiveness.
5alpha-reductase type 2 and Androgen receptor compose the androgen responsiveness of the Gonadotropin-releasing hormone (GnRH) GT1-1 neurons / A. Poletti, A. Rampoldi, F. Piccioni, N. Ponti, S. Simeoni, S. Volpi, M. Zanisi, L. Martini. - In: JOURNAL OF NEUROENDOCRINOLOGY. - ISSN 0953-8194. - 13:4(2001), pp. 353-357.
|Titolo:||5alpha-reductase type 2 and Androgen receptor compose the androgen responsiveness of the Gonadotropin-releasing hormone (GnRH) GT1-1 neurons|
POLETTI, ANGELO (Primo)
ZANISI, MARIAROSA GIULIANA (Penultimo)
MARTINI, LUCIANO (Ultimo)
|Parole Chiave:||α-reductase; Androgen receptor; GnRH; Neurones|
|Settore Scientifico Disciplinare:||Settore BIO/13 - Biologia Applicata|
Settore MED/13 - Endocrinologia
|Data di pubblicazione:||2001|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1046/j.1365-2826.2001.00635.x|
|Appare nelle tipologie:||01 - Articolo su periodico|