نتایج جستجو برای: reproductive activity

تعداد نتایج: 1222977  

2012
J. Scott Keogh Daniel W. A. Noble Eleanor E. Wilson Martin J. Whiting

Activity patterns and social interactions play a key role in determining reproductive success, although this is poorly understood for species that lack overt social behaviour. We used genetic paternity analysis to quantify both multiple paternity and the relative roles of activity and social behaviour in determining reproductive success in a nondescript Australian lizard. During the breeding se...

Ali Ghorashi Hossein Hayatgheybi, Mahzad Akbarpour Masoud Houshmand

Background Ghezel sheep are highly prolific and one of the local sheep breeds in Iran and Turkey. Growth differentiation factor-9 (GDF9) gene has been found to be essential for growth and differentiation of early ovarian follicles. Novel mutations in GDF9 have been associated with increased ovulation rates and high litter sizes in heterozygous carriers. Therefore, fecundity gene for GDF9 (FecGH...

Journal: :Theriogenology 2013
Daniel Dantas Wildner Harry Grier Irani Quagio-Grassiotto

The objective was to characterize female germ cell renewal during the annual reproductive cycle in two species of ostariophysian fish with distinct reproductive strategies: a siluriform, Pimelodus maculatus, in which oocyte development is group synchronous and the annual reproductive period is short; and a characiform, Serrasalmus maculatus, with asynchronous oocyte development and a prolonged ...

Journal: :The Journal of endocrinology 2002
K L Hull S Harvey

It is now well established that exogenous GH promotes sexual maturation and reproductive function. The possibility that this may reflect physiological actions of endogenous GH has, however, rarely been considered. Correlative changes in GH secretion and reproductive state (puberty, pregnancy, lactation, menopause and ovarian cycles) are thus the primary focus of this review. GH secretion is, fo...

Journal: :Revista de biologia tropical 2012
Lilian E Ferré Daniel A Medesani C Fernando García Matías Grodzielski Enrique M Rodríguez

The freshwater crayfish Cherax quadricarinatus is a tropical species of great interest for aquaculture. Vitellogenin (Vg), a lipoprotein precursor of the vitellum accumulated in spawned eggs, can be synthesized in the ovary and/or hepatopancreas of most crustaceans, being the hemolymph the way for transporting Vg throughout the reproductive cycle. Concentration of Vg in hemolymph, ovary and hep...

Journal: :Environmental Health Perspectives 2000
J M Moline A L Golden N Bar-Chama E Smith M E Rauch R E Chapin S D Perreault S M Schrader W A Suk P J Landrigan

The discovery in the mid-1970s that occupational exposures to pesticides could diminish or destroy the fertility of workers sparked concern about the effects of hazardous substances on male reproductive health. More recently, there is evidence that sperm quantity and quality may have declined worldwide, that the incidence of testicular cancer has progressively increased in many countries, and t...

Journal: :Journal of environmental biology 2006
D S Shankar R S Kulkarni

In the present study, effect of cortisol on the ovary of the freshwater fish Notopterus notopterus was studied during four phases of the reproductive cycle. The hormone was injected 60microg/fish for ten days. Cortisol in fish is known to increase the metabolic activity. After the hormone treatment the ovarian somatic index and the hepatosomatic index increases during non breeding phase. The yo...

Journal: :Reproductive biology 2018
Kristyn E Sylvia Tierney K Lorenz Julia R Heiman Gregory E Demas

Although research has shown interactions between the reproductive system and energy homeostasis, it is not clear how environmental or behavioral factors may factor into these associations. Here we aimed to determine how changes in reproductive state (i.e., phase of the menstrual cycle) and other behavioral and physiological factors may influence leptin levels in healthy women, as well as how se...

Journal: :Environmental entomology 2012
W Rodney Cooper Dale W Spurgeon

Lygus hesperus Knight (Hemiptera: Miridae) is a key pest of cotton (Gossypium spp.) in the western United States that injures floral buds (squares) and developing fruit (bolls). However, no clear relationship between Lygus population level and plant injury has been established. Age-dependent feeding activity by L. hesperus is a possible source of variation that has not been examined for its in...

Journal: :Molecules 2010
Marjana Novic Marjan Vracko

Reproductive toxicity is an important regulatory endpoint, which is required in registration procedures of chemicals used for different purposes (for example pesticides). The in vivo tests are expensive, time consuming and require large numbers of animals, which must be sacrificed. Therefore an effort is ongoing to develop alternative In vitro and in silico methods to evaluate reproductive toxi...

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