Systematic shut-off of the hormone receptors in intraspecific adrenal x Leydig cell hybrids.
The mouse Y1 adrenal cell line was fused with mouse Leydig cells in primary culture. The selected hybrids were examined for their response to gonadotropin (hCG) and ACTH. None of them bound specifically [125I]hCG, nor did they augment their cAMP production in response to gonadotropin or ACTH stimulation, whereas their adenylate cyclase remained responsive to forskolin and cholera toxin, thus indicating a repression of hCG receptor synthesis and probably a loss of ACTH receptors, rather than a lesion of the coupling between the hormone receptor complex and the adenylate cyclase. Basal pregnenolone production in 17 hybrids was close to that of Leydig and Y1 cells and was enhanced after 8-bromo adenosine 3',5'-monophosphate (8-Br-cAMP) stimulation in 11 of them. Therefore, the negative control leading to the extinction of both parental functions acts preferentially at the first step of steroidogenesis, i.e., the gene(s) coding for the hormone receptors.
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism; D000311:Adrenal Glands / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis; D005786:Gene Expression Regulation; D006822:Hybrid Cells / Q000378:metabolism*; D007621:Karyotyping; D007985:Leydig Cells / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice; D011284:Pregnenolone / Q000096:biosynthesis; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics; D018043:Receptors, Corticotropin; D011974:Receptors, LH
D011956:Receptors, Cell Surface; D018043:Receptors, Corticotropin; D011974:Receptors, LH; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D011284:Pregnenolone; D002772:Cholera Toxin; D000242:Cyclic AMP; D000262:Adenylyl Cyclases