Endocrine Abstracts

Even before the current economic crisis, life in academia was already tough enough, with a distinct lack of career structure for basic scientists. Now that funding levels continue to plummet, a career in academia seems even less attractive. However, for many basic scientists, it is still their major aspiration; to gain a faculty position that allows them to pursue their research interests. I was hopelessly naive to what life as a University Lecturer was going to involve. Two d...

Five years after my original post-doc experience overseas, I find myself increasingly contemplating the benefits of that time in my career and whether it was the right decision. Over that same period of time, it’s still clear to me that despite the introduction of a few more research fellowships for the privileged few, the career structure of basic scientists in the UK still appears to be virtually non-existent. So should you consider moving abroad?...

Particulate guanylyl cyclases are expressed in all endocrine organs and serve as specific receptors of the natriuretic peptides ANP, BNP and CNP. Guanylyl cyclase-B (GC-B/Npr2) receptors specifically mediate the biological effects of CNP in its target tissues. Targeted disruption of either CNP or GC-B results in pituitary growth hormone deficiency and dwarfism as a result of achondroplasia. Despite this, molecular regulation of GC-B expression is poorly elucidated. Therefore, ...

CNP, the third peptide of the mammalian natriuretic peptide family, exerts its biological effects through activation of the guanylyl cyclase B (GC-B) receptor and resulting cGMP accumulation. Our previous studies reported that CNP stimulates phosphorylation of MAPK family proteins in GH3 somatotrophs. This present study aimed to further characterise the mechanism of CNP-stimulated ERK phosphorylation and resulting biological consequences in GH3 cells. Western blot analyses sho...

Natriuretic peptides, ANP, BNP and CNP, exert the majority of their effects via particulate guanylyl cyclase receptors (GC-A or GC-B), resulting in increased cellular cGMP levels. Several studies have examined the pharmacological properties of GC-B receptors in many systems, and desensitization (tachyphylaxis, loss of response) has been reported to occur. Targeted deletion (in mice) or genetic mutations (in humans) of the GC-B receptor have been implicated in a dwarfism phenot...

Gonadotrophs have previously been shown to be the predominant source of C-type natriuretic peptide (CNP) in the anterior pituitary, and CNP causes enhanced cGMP accumulation in αT3-1 gonadotrophs. However, the biological role of CNP in gonadotrophs remains elusive. In the current study, we examined the molecular and functional characteristics of the gonadotroph natriuretic peptide system. Using two well-characterised gonadotroph cell lines of different developmental origi...

Cortisol is metabolised by two 11βHSD isoenzymes. Recently, we reported that 11βHSD1 and 11βHSD2 mRNA and protein are co-expressed in boar testis and throughout the male reproductive tract. However, enzyme activities were only detectable in boar testis, caput epididymidis, bulbourethral glands and penile urethra. The objective of the present study was to assess whether cortisol–cortisone metabolism in the boar testis and caput epididymidis could be regulate...

GnRH is secreted in pulses and its effects on pituitary gonadotropes depend on pulse frequency. This is crucial for physiological control and therapeutic manipulation of the system (in IVF and treatment of hormone-dependent cancers) but GnRH pulse frequency decoding mechanisms are unknown. The simplest form of frequency dependence is a linear relationship between integrated inputs and outputs but such ‘integrative tracking’ cannot explain the bell-shaped frequency-re...

GnRH acts via G-protein coupled receptors to stimulate synthesis and secretion of luteinizing hormone and follicle-stimulating hormone. GnRH activates phospholipase C, causing calcium mobilisation and influx, activation of protein kinase C and stimulation of mitogen-activated protein kinase cascades. GnRH is secreted in brief pulses with each pulse causing rapid and transient activation of extracellular signal regulated kinases (ERKs) (1), yet very little is known about what s...

CNP, the third member of the mammalian natriuretic peptide family, exerts the majority of its biological effects via the guanylyl cyclase B (GC-B) receptor, resulting in accumulation of intracellular cGMP. Previous studies reveal numerous inhibitory effects of natriuretic peptides on the MAPK family in bone, neuronal and cardiovascular tissues. However, we recently reported that CNP stimulates ERK, p38MAPK and JNK phosphorylation in pituitary GH3 somatotrophs. As CNP is known ...