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We have studied a kindred with three siblings with isolated hypogonadotropic hypogonadism caused by compound heterozygote mutations in the GnRH receptor gene. The disorder was transmitted as an autosomal recessive trait. The R262Q mutation in intracellular loop 3 of the receptor was associated with a mutation in the third transmembrane domain of the(More)
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) result from the assembly of a common subunit alpha and a unique subunit beta, expressed in the same cell by single, structurally-related genes. In order to compare the intrinsic stability of the alpha, LH beta and FSH beta mRNA transcripts, we used cultured rat pituitary cells incubated in(More)
The effects and respective influence of pituitary adenylate cyclase-activating polypeptide (PACAP) and gonadotropin-releasing hormone (GnRH) on cyclic AMP (cAMP) production in pituitary gonadotropes were analyzed using the LbetaT2 cell line. Both hormones induced cAMP with, however, different intensity and time course. In addition, the GnRH effect was(More)
The identification of gonadal gonadotropin-releasing hormone receptors (GnRH-R) and evidence of direct inhibitory effects of GnRH agonists upon steroidogenesis in adult rat gonads, lend credence to a putative intragonadal role of a locally secreted GnRH or GnRH-like peptide. Using reverse transcription-polymerase chain reaction followed by Southern blot(More)
In the pituitary of mammals, the GnRH receptor (GnRHR) plays a primary role in the control of reproductive function. It is further expressed in the hippocampus, where its function, however, is not well defined. By quantitative RT-PCR analyses, we demonstrate herein that the onset of GnRHR gene (Gnrhr) expression in the rat hippocampus was unexpectedly(More)
Normal gametogenesis and steroidogenesis is highly dependent on the pulsatile release of hypothalamic GnRH that binds high-affinity receptors present at the surface of pituitary gonadotrophs thereby triggering the synthesis and release of the gonadotropins LH and FSH. The mammalian GnRH receptor displays the classical heptahelical structure of G(More)
The gonadotropin-releasing hormone (GnRH) pulsatile pattern is critical for appropriate regulation of gonadotrope activity but only little is known about the signaling mechanisms by which gonadotrope cells decode such pulsatile pattern. Here, we review recent lines of evidence showing that the GnRH receptor (GnRH-R) activates the cyclic AMP (cAMP) pathway(More)
We have recently provided evidence that the concentration and activity of the enzyme nitric oxide synthase type I (NOS I) was stimulated in gonadotrophs by GnRH, suggesting a role for the NOS I/NO pathway in the GnRH control of cell functions. To further establish the GnRH regulation of pituitary NOS I under physiological circumstances, we have examined the(More)
Nitric-oxide synthase type I (NOS I) is expressed primarily in gonadotrophs and in folliculo-stellate cells of the anterior pituitary. In gonadotrophs, the expression and the activity of NOS I are stimulated by gonadotropin-releasing hormone (GnRH) under both experimental and physiological conditions. In the present study, we show that pituitary adenylate(More)
Growth factors are known to play diverse roles in steroidogenesis, a process regulated by the mitochondrial steroidogenic acute regulatory (StAR) protein. The mechanism of action of one such growth factor, IGF-I, was investigated in mouse Leydig tumor (mLTC-1) cells to determine its potential role in the regulation of StAR expression. mLTC-1 cells treated(More)