Bovine C-terminal octapeptide of RFamide-related peptide-3 suppresses luteinizing hormone (LH) secretion from the pituitary as well as pulsatile LH secretion in bovines     

H. Kadokawa  M. Shibata  Y. Tanaka  T. Kojima  K. Matsumoto  K. Oshima  N. Yamamoto 《Domestic animal endocrinology》2009,36(4):219-224

Gonadotropin-inhibiting hormone (GnIH), observed in quail as a member of the RFamide neuropeptide family, suppresses luteinizing hormone (LH) secretion from the avian pituitary. Rats and cattle have an active gene of another member of the RFamide neuropeptide family, termed RFamide-related peptide-3 (RFRP-3), although bovine RFRP-3 is different from that of rats in both length and amino-acid sequence. A single injection of GnIH or RFRP-3 inhibited LH secretion in rodents, which continued for various periods. This study was conducted to evaluate the effects of bovine C-terminal octapeptide of RFRP-3 (RFRP-3-8) on LH secretion from cultured anterior pituitary (AP) cells of cattle, and the effects of RFRP-3-8 injections on pulsatile LH secretion in castrated male calves. The suppressive effect of RFRP-3-8 on LH secretion from AP cells was observed in the presence of gonadotropin-releasing hormone (GnRH), but not in the absence of GnRH in culture media. In another experiment collecting blood samples serially from castrated male calves with repeated intravenous injections of RFRP-3-8 (n = 6) or saline (n = 6), the RFRP-3-8 group showed suppressed LH pulse frequency during the injection period (P < 0.05); however, the RFRP-3-8 group showed no difference from the saline group in all measures of LH secretion in the postinjection period. In conclusion, our results suggested that RFRP-3-8 suppresses LH secretion from cultured AP cells, as well as LH pulse frequency in cattle.  相似文献   

The influence of warp length on trawl dimension and catch of walleye pollock <Emphasis Type="Italic">Theragra chalcogramma</Emphasis> in a bottom trawl survey     

Yasuzumi?FujimoriEmail author  Kenji?Chiba  Tatsuki?Oshima  Kazushi?Miyashita  Satoshi?Honda 《Fisheries Science》2005,71(4):738-747

ABSTRACT:   Variations in trawl dimension, bottom contact, and catch with differing warp lengths during walleye pollock surveys conducted by the Fisheries Research Agency were examined. The ratio of warp length to fishing depth (scope ratio) was set at 2.5, 3.0 and 3.5 at depths of 110 m. At a 2.5 scope ratio, the net mouth shape and footgear contact fluctuated, as the trawl door did not contact the bottom. Footgear contact was complete when the scope ratio was 3.0 or more. Walleye pollock, sculpins and flatfishes were the main catch in all tows, and the catch increased with scope ratio. There was no difference in the length frequency of walleye pollock ( n  = 300) captured at 2.5 and 3.0 scope ratio. However, the length frequency at 3.5 was significantly different from that of other scope ratios. These results suggest that at a scope ratio of 3.0 or more, the trawl door will not leave the bottom at any depths. To compliment echo surveys for walleye pollock, a 3.0 scope ratio would be optimal, since the catch data for a 3.5 scope ratio was dissimilar from that of scope ratios.  相似文献