Diminished expression of ACTH signaling proteins and steroidogenic limiting factors in adrenocortical cells isolated from halothane nn pigs

Previous studies demonstrated significantly lower plasma cortisol level in homozygous halothane-positive (Hal nn) pigs, as compared with homozygous halothane-negative (Hal NN) pigs. To determine whether such difference is attributed to the fundamental alterations in adrenocortical function, F1 offsprings from Pietrain (Hal nn)xErhualian (Hal NN) were intercrossed to produce F2 sibling pigs with segregated genotypes. Adrenocortical cells were isolated from the Hal nn and Hal NN F2 pigs, respectively, and cultured with or without ACTH challenge. Cortisol levels in culture medium, as well as the content of MC2R, cAMP, CREB, phosphorylated CREB (pCREB), StAR and P450scc in adrenocortical cell lysates, were determined. Cortisol, cAMP, StAR and P450scc levels were significantly lower in Hal nn adrenocortical cells under basal condition without ACTH challenge. ACTH significantly increased cortisol level in the medium and the protein content of MC2R, StAR, P450scc in adrenocortical cell lysates, regardless of genotypes. Total CREB protein content was not different between genotypes and treatments, whereas pCREB content exhibited significant effects of genotype and treatment, being higher in Hal NN than in Hal nn under basal condition and in response to ACTH challenge. These results indicate that the compromised cAMP/PKA/pCREB signaling pathway of ACTH and diminished expression of limiting factors in adrenocortical steroidogenesis (StAR and P450scc) may contribute to the significantly lower plasma cortisol levels in Hal nn pigs.     

Concentrations of free steroids in the jugular and hepatic portal veins of pigs after ingestion of testosterone, estrogen, or progesterone or transplantation of ovaries to the intestine.

Estrogen, progesterone or testosterone were administered orally to ovariectomized gilts fitted with indwelling catheters. Blood samples were taken from the jugular and hepatic portal veins at intervals varying from a few minutes to daily over periods that varied from 1 d to several months. Concentrations of free steroids rose dramatically in the hepatic portal vein within a few min of feeding steroids and remained high for 3-8 hr before declining to base levels. Concentrations in the jugular vein sometimes rose very slightly for the same period. At 48 hr after administration the concentrations remained at baseline in the hepatic portal vein, but rose several-fold in the jugular and remained elevated for several days. Autotransplantation of the ovaries to the intestine resulted in very large ovaries consisting of many large, heavily luteinized cystic follicles. Concentrations of progesterone and estrogen in the hepatic portal vein were very high, but were low in the jugular vein. The gut wall allows for passage of some orally administered free steroids to the liver via the hepatic portal vein. The free steroids are essentially metabolized before they reach the jugular vein, but can be recirculated via the enterohepatic route.     

Long-term effects of intermittent equine parathyroid hormone fragment (ePTH-1-37) administration on bone metabolism in healthy horses

Intermittent administration of parathyroid hormone (PTH) is an anabolic therapy for osteoporotic conditions in humans. This study evaluated the effects of equine PTH fragment (ePTH-1-37) administration on bone metabolism in 12 healthy horses. Six horses each were treated once daily for 120days with subcutaneous injections of 0.5μg/kg ePTH-1-37 or placebo. Blood was collected to determine ionized calcium (Ca(++)), total Ca (Ca(T)), inorganic phosphorus, serum equine osteocalcin (eOC), carboxy-terminal telopeptide of type I collagen (ICTP), bone-specific alkaline phosphatase, and carboxy-terminal cross-linked telopeptide of type I collagen. Bone mineral density (BMD) was determined with dual X-ray absorptiometry of the metacarpus and calcaneus. Significantly higher blood Ca(++) and plasma Ca(T) concentrations were measured 5h after ePTH-1-37 administration compared to placebo. Higher serum eOC concentrations were found for ePTH-1-37 treatment at days 90 (P<0.05) and 120 (P=0.05). Significantly higher serum ICTP levels were observed with ePTH-1-37 treatment at days 60 and 90. For both study groups, BMD increased significantly in the calcaneus. Long-term use of ePTH-1-37 seemed to have no negative effects on bone metabolism in healthy horses. The absence of undesirable side effects is the premise to ensure safety for further clinical investigations in horses with increased bone resorption processes.     

Distribution, fauna and seasonal variation of sandflies, simultaneous detection of nuclear internal transcribed spacer ribosomal DNA gene of Leishmania major in Rhombomys opimus and Phlebotomus papatasi, in Natanz district in central part of Iran

Background: Zoonotic cutaneous leishmaniasis (ZCL) due to Leishmania major is increasing in many parts of Iran. This disease originally is a disease found in gerbils. Leishmania parasites are transmitted by sandflies that live and breed in gerbil burrows. Nested PCR amplified Leishmania ITS1-5.8S rRNA gene in both main reservoir host “Rhombomys opimus” and in the “Phlebotomus papatasi” main vector of ZCL, in Iran. Population differentiation and seasonal variation of sandflies were analyzed at a microgeographical level in order to identify any isolation by distance, habitat or seasons. Methods: Populations of sandflies were sampled from the edges of villages in Natanz, Isfahan province, Iran, using the Centers for Disease Control traps and sticky papers. Individual sandflies were identified based on external and internal morphological characters. Nested PCR protocols were used to amplify Leishmania ITS1-5.8S rRNA gene, which were shown to be species-specific via DNA sequence. Results: A total of 4500 sandflies were collected and identified. P. papatasi, Phlebotomus sergenti and Phlebotomus jacusieli from genus Phlebotomus and Sergentomyia sintoni and Sergentomyia clydei from genus Sergentomyia were identified in this region. P. papatasi was the most abundant sandfly in the collections. Ten out of 549 female P. papatasi and four out of 19 R. opimus were found to be infected with L. major. Conclusion: Seasonal activity of sandflies starts in June and ends in November. Abundance of P. papatasi was in September. Finding and molecular typing of L. major in P. papatasi and R. opimus confirmed the main vector and reservoir in this region.Key Words: Leishmania major, Sandflies, Leishmaniasis, Iran