Differential involvement of protein kinase C and protein kinase A in ghrelin-induced growth hormone and gonadotrophin release from goldfish (Carassius auratus) pituitary cells.

Ghrelin (GRLN) and its receptor have been identified and characterised in goldfish brain and the pituitary, and recent evidence shows that goldfish (g)GRLN(19) induces both growth hormone (GH) and maturational gonadotrophin (LH) release through an extracellular Ca(2+) -dependent mechanism in goldfish. To further understand the role of GRLN in hormone release, the present study examined the involvement of protein kinase C (PKC) and protein kinase A (PKA) in gGRLN(19) -induced GH and LH release and corresponding Ca(2+) signals in primary cultures of goldfish pituitary cells. Treatments with PKC inhibitors, Bis-II and Gö 6976, significantly reduced gGRLN(19) -induced GH and LH release and their corresponding intracellular Ca(2+) signals in identified somatotrophs and gonadotrophs, respectively. gGRLN(19) was unable to further stimulate hormone release or Ca(2+) signals when cells were pretreated with the PKC agonist, DiC8. PKA inhibitors, H-89 and KT 5720, inhibited gGRLN(19) -induced LH release and Ca(2+) signals in gonadotrophs but not GH release or Ca(2+) signals in somatotrophs. Interestingly, pretreatment of pituitary cells with the adenylate cyclase activator forskolin potentiated gGRLN(19) -induced GH, but not LH, release, although it had no effect on intracellular Ca(2+) signals in either cell type. Taken together, the results suggest that PKC is an important intracellular component in gGRLN(19) -induced GH and LH release, whereas PKA is involved in gGRLN(19) -elicited LH release. Furthermore, the PKA pathway potentiates gGRLN(19) -induced GH release via a Ca(2+) -independent mechanism. Overall, the present study provides insight into the neuroendocrine regulation of GH and LH release by elucidating the mechanistic aspects of GRLN, a hormone involved in many critical physiological processes, including pituitary functions.

The secretogranin II-derived peptide secretoneurin stimulates luteinizing hormone secretion from gonadotrophs.

Secretoneurin (SN) is a 33- to 34-amino acid neuropeptide derived from secretogranin-II, a member of the chromogranin family. We previously synthesized a putative goldfish (gf) SN and demonstrated its ability to stimulate LH release in vivo. However, it was not known whether goldfish actually produced the free SN peptide or whether SN directly stimulates LH release from isolated pituitary cells. Using a combination of reverse-phase HPLC and mass spectrometry analysis, we isolated for the first time a 34-amino acid free gfSN peptide from the whole brain. Moreover, Western blot analysis indicated the existence of this peptide in goldfish pituitary. Immunocytochemical localization studies revealed the presence of SN immunoreactivity in prolactin cells of rostral pars distalis of the anterior pituitary. Additionally, we found that magnocellular cells of the goldfish preoptic region are highly immunoreactive for SN. These neurons send heavily labeled projections that pass through the pituitary stalk and innervate the neurointermediate and anterior lobes. In static 12-h incubation of dispersed pituitary cells, application of SN antiserum reduced LH levels, whereas 1 and 10 nM gfSN, respectively, induced 2.5-fold (P < 0.001) and 1.9-fold (P < 0.01) increments of LH release into the medium, increases similar to those elicited by 100 nM concentrations of GnRH. Like GnRH, gfSN elevated intracellular Ca(2+) in identified gonadotrophs. Whereas we do not yet know the relative contribution of neural SN or pituitary SN to LH release, we propose that SN could act as a neuroendocrine and/or paracrine factor to regulate LH release from the anterior pituitary.

La fasciolasis en Jamaica: aspectos epidemiológicos y económicos de una zoonosis parasitaria transmitida por caracoles / Fasciolasis in Jamaica: epidemiologic and economic aspects of a snail-borne parasitic zoonosis

La fasciolasis es endémica en Jamaica. En este estudio se emplean datos obtenidos en encuestas y otros relacionados con la producción de ganado, para evaluar la salud animal, la salud pública veterinaria y las repercusiones económicas de la enfermedad (AU)

La fascioliasis en Jamaica: aspectos epidemiológicos y económicos de una zoonosis parasitaria transmitida por caracoles / Fascioliasis in Jamaica: epidemiological and economical aspects of a snail-borne parasitic zoonosis

Las fascioliasis es endémica en Jamaica. En este estudio se emplean datos obtenidos en encuestas y otros relacionados con la producción de ganado, para evaluar la salud animal, la salud pública veterinaria y las repercusiones económicas de la enfermedad

Fascioliasis in Jamaica: epidemiologic and economic aspects of a snail-borne parasitic zoonoses

This study attempts to quantify the animal health, veterinary public health, and economic impact of fascioliasis in Jamaica. A coprologic survey conducted for this purpose in late 1979 and early 1980 revealed an overall fascioliasis prevalence of at least 22.2 percent (n=520) in cattle and 17.2 percent (n=514) in goats. In general the prevalence of the disease was found to be directly correlated with rainfall and inversely correlated with altitude. Four ecological zones of endemicity were identified and related to the epidemiology of the intermediate host, Fossaria cubensis. The economic cost of the disease was estimated from production statistics and a questionnaire survey. Losses were categorised as either direct (due mainly to liver condemnation and suboptimal dairy or beef production) or indirect (due mainly to treatment costs). The estimate did not include the less quantifiable costs associated with mortality, provision of veterinary services, and lost opportunities for development. The total economic cost of fascioliasis in Jamaica, as indicated by the above data, appears to be on the order of J$2.4 million (J$1.78=US1.00); and if anticipated improvements in Jamaica's livestock industry are allowed for, this total rises to J$3.2 million. It is noteworthy that a significant share of this cost would be in scarce foreign exchange spent on drugs and on imported substitutes for local meat and dairy products. It should also be recalled that fascioliasis is a zoonosis producing significant numbers of human cases in the Greater Antilles, and that inappropriate changes in vegetable cultivation practices could cause it to become a significant health problem in Jamaica. Finally, there is a very real danger that proposed increases in Jamaica's cattle and sheep herds could enormously increase the prevalence of the disease, as has happened elsewhere. It is therefore recommended that development of the country's livestock industry be paralled by development of an appropriate fascioliasis control strategy. Such a planned approach to fascioliasis control, which tends to be relatively cost-effective, confines treatment to the periods and localities at greatest risk and uses animal management techniques to reduce the incidence of infection (Summary)

Pasteurella haemolytica in the tracheal air of calves.

Pasteurella haemolytica was shown to be present in the tracheal air of calves and was likely transported in droplet nuclei formed in the nasal passages. The number of colonies of P. haemolytica found in the tracheal air of the calves ranged from 1.9 to 12.5 colonies per cu ft of air. As long as P. haemolytica colonized the nasal passage in numbers detectable in nasal swabs it could be found in the tracheal air but there was no direct correlation between the numbers in the nasal flora and the numbers found in the tracheal air. Of the P. haemolytica which travel via the tracheal air 47.8% were in droplets of the aerodynamic size of from less than one to five microns, the size range which is considered hazardous for lung penetration in man. The technique used demonstrated the presence of P. haemolytica in the tracheal air of calves and provides a useful tool for monitoring and determining the phase in the colonization of the respiratory tract in which the majority of the potential pathogen P. haemolytica pass from the nose to the tracheal air and presumably to the lung.

La fasciolasis en Jamaica: aspectos epidemiológicos y económicos de una zoonosis parasitaria transmitida por caracoles / Fasciolasis in Jamaica: epidemiologic and economic aspects of a snail-borne parasitic zoonosis

La fasciolasis es endémica en Jamaica. En este estudio se emplean datos obtenidos en encuestas y otros relacionados con la producción de ganado, para evaluar la salud animal, la salud pública veterinaria y las repercusiones económicas de la enfermedad (AU)