Seasonal variation in haematological parameters in male and female Tinca tinca

This study was designed to investigate any seasonal (spring, summer, autumn and winter) changes in haematological parameters in the blood of Tinca tinca measuring the number of red blood cells (RBC), haematocrit, white blood cells, and total plasma proteins.The results show significant changes in RBC and haematocrit in males comparing spring and summer with autumn and winter, whereas in females the RBC remained constant for all 4 seasons but the haematocrit decreased in autumn and winter compared to spring and summer. The white blood cells of male and female animals were significantly lower in spring and winter compared to summer and autumn. In male fish total protein contents significantly decreased in autumn and winter compared to spring and summer, whereas in females protein output significantly decreased in winter compared to the other seasons. The results indicate marked seasonal variation in the blood of male and female Tinca tinca. This variation may play a important protective role for the survival of the animals.     

Activity Monitoring of the Inhabitants in Tauwema,a Traditional Melanesian Village: Rest/Activity Behaviour of Trobriand Islanders (Papua New Guinea)

The inhabitants of Tauwema village represent a traditionally living society. Altogether, 39 inhabitants belonging to seven families were included in this study. Families or people living in one household were preferentially chosen for monitoring particularly the effects of social zeitgebers and synchronization within families. They were observed continuously for 7 consecutive days using microelectronic actometers that register locomotor activity with a sampling period of 2 minutes and a resolution of 7 bit. The activity data obtained showed that in young infants circadian patterns develop out of ultradian components dominating in the first months of life. The rhythmicity of the adults was well-related to the natural light-dark cycle, combined with a strong social component which is reflected in a comparatively small intra- and inter-individual variability in the time of the end of the main sleep span in the morning, while the variability in the beginning of the main sleep period in the evening is much greater. The mean sleep duration of the younger infants (up to 11 months; n =4) varied between 9 and 12 h per day and that of the adults (n = 23) between 7 and 10 h. Gender-specific differences occurred in married couples with wives having a longer sleep duration in 7 out of 9 cases.     

哺乳动物季节性繁殖的神经内分泌调节机制

动物的季节性繁殖,是指其繁殖活动从静止到复苏的一个年周期性循环。研究显示,kisspeptin和RFRP对繁殖的季节性变化具有重要作用。非繁殖期最显著的特点是雌激素对GnRH分泌的负反馈效应的增加,而雌激素的这种效应是由kisspeptin神经元传导的。因此,kisspeptin是影响繁殖活动的一个重要因子。RFRP的表达依赖于褪黑激素的分泌并呈现出季节性变化,在非繁殖期对繁殖活动的抑制作用非常明显。此外,甲状腺激素在繁殖期的终止上发挥着至关重要的作用,而多巴胺能神经元A14/A15也促进了雌激素负反馈效应的季节性变化。这些神经元系统通过协同作用一起调节了生殖功能随光周期的季节性转变。文章对繁殖的季节性和这4个神经内分泌系统之间的关系进行了系统的阐述。     

Population genetics of Great Basin feral horses

The genetic make-up of Great Basin wild (feral) horses was investigated by blood typing studies. Blood samples of 975 feral horses from seven trap sites in Nevada and Oregon were tested by serological and electrophoretic techniques for genetic markers at 19 polymorphic loci. The average number of variants for the seven feral populations [72·1 ± 3·2 (SEM), range 62–85] was not significantly different from that of 16 domestic breeds (75·0 ± 11·5, range 58–105). The expected average frequency of heterozygotes per locus (average heterozygosity) for the feral populations (0·402 ± 0·009, range 0·368–0·442) was not significantly different from the domestic breeds (0·389 ± 0·045, range 0·295–0·443). Dendrograms constructed using pairwise comparisons of Nei's distance measurements substantiated anecdotal accounts of the origins of Great Basin horses from Iberian, American saddle horse and draft horse breeds.     

哺乳动物季节性繁殖的神经内分泌调节机制

动物的季节性繁殖, 是指其繁殖活动从静止到复苏的一个年周期性循环。研究显示, kisspeptin和RFRP对繁殖的季节性变化具有重要作用。非繁殖期最显著的特点是雌激素对GnRH分泌的负反馈效应的增加, 而雌激素的这种效应是由kisspeptin神经元传导的。因此, kisspeptin是影响繁殖活动的一个重要因子。RFRP的表达依赖于褪黑激素的分泌并呈现出季节性变化, 在非繁殖期对繁殖活动的抑制作用非常明显。此外, 甲状腺激素在繁殖期的终止上发挥着至关重要的作用, 而多巴胺能神经元A14/A15也促进了雌激素负反馈效应的季节性变化。这些神经元系统通过协同作用一起调节了生殖功能随光周期的季节性转变。文章对繁殖的季节性和这4个神经内分泌系统之间的关系进行了系统的阐述。     

Influence of short-term oestradiol treatment on plasma thyroid hormone kinetics in rainbow trout, Salmo gairdneri

The effects of 17β-oestradiol (E₂) on plasma kinetics of thyroid hormones (T₄, l-thyroxine; T₃, 3,5,3′-triiodo-l-thyronine) were studied in immature rainbow trout. E₂-3-benzoate (0.5 mg/100 g) was injected intraperitoneally on days 0 and 3, and on the morning of day 4 each trout received an intracardiac injection of either [¹²⁵I]T₄ and Na ¹³¹I or [^I25I]T₃. Groups of trout were bled and killed from 5 min to 4 days post-injection of tracer. E₂ did not alter the plasma T₄ level but depressed the T₄ plasma clearance rate, plasma-to-total tissue flux of T₄ and thyroidal T₄ secretion rate. Monodeiodination of T₄ to T₃ was also depressed, as judged from plasma [^I25I]T₃ and ^I25I ^? levels in [¹²⁵I]T₄-injected trout. E₂ had no major effect on T₃ plasma clearance rate but depressed the plasma T₃ level, plasma-to-total tissue flux of T₃ and the T₃ plasma appearance rate. E₂ had no influence on biliary transport of [^I25I]T₄ or [¹²⁵I]T₃. The above results suggest that E₂, at the dose range employed, depresses extrathyroidal T₄ to T₃ conversion, which may in turn decrease plasma T₄ clearance and thyroidal T₄ secretion.     

The effect of mildronate and related substances on levels of thyroid hormones and some intermediates of lipid and carbohydrate metabolism in hyperthyroid and hypothyroid rats

The effects of mildronate [3(2,2,2-trimethylhydrazinium) propionate dihydrate], γ-butyrobetaine (GBB) and their combination (neomildronate) on the level of thyroid hormones and some intermediates of basal metabolism (free fatty acids, triglycerides, glucose) in serum of laboratory rats with various dysfunctions of thyroid glands including idiopathic hyperfunction and also hypofunction induced by administration of 6-propyl-2-thiouracil (PTU) or L-carnitine administration. Intraperitoneal injections of mildronate (150 mg/kg) during 20 days to male Wistar rats with elevated level of thyroid hormones and basal metabolism normalized thyroxin level and parameters of lipid metabolism in serum. Administration of the compounds studied to rats with hypothyroidism induced by administration of PTU or L-carnitine did not influence natural recovery of the hormonal level. Possible biochemical role of these pharmacological treatments is discussed in terms of in regulation of thyroid gland function.