Associations between plasma testosterone levels and season, nutritional status, age, and body size in free-ranging male Asian black bears (Ursus thibetanus) in central Honshu, Japan

2021 ◽  
pp. 113794
Author(s):  
Jumpei Tomiyasu ◽  
Mitsunori Kayano ◽  
Ken Hazano ◽  
Motozumi Matsui ◽  
Yui Nemoto ◽  
...  
Keyword(s):  
Body Size ◽  
Nutritional Status ◽  
Black Bears ◽  
Plasma Testosterone ◽  
Ursus Thibetanus ◽  
Testosterone Levels ◽  
Free Ranging

scholarly journals Testosterone is associated with harem maintenance ability in free-ranging grey-headed flying-foxes, Pteropus poliocephalus

2009 ◽  
Vol 5 (6) ◽  
pp. 758-761 ◽  
Author(s):  
Stefan M. Klose ◽  
Justin A. Welbergen ◽  
Elisabeth K. V. Kalko
Keyword(s):  
Plasma Testosterone ◽  
Flying Foxes ◽  
Mating Period ◽  
Social Challenges ◽  
Testosterone Levels ◽  
Harem Size ◽  
Pteropus Poliocephalus ◽  
Original Size ◽  
Complex Forms ◽  
Free Ranging

Males of many vertebrate species aggressively defend their reproductive interests by monopolizing females, and the ‘challenge hypothesis’ predicts that testosterone levels in reproductive contexts rise to facilitate males' competitive behaviours necessary for meeting social challenges. The hypothesis is successful in explaining patterns of testosterone secretion in many avian species, but remains comparatively unexplored in mammals. ‘Circulating plasma testosterone levels (T)’ were studied in relation to harem maintenance in grey-headed flying-foxes, Pteropus poliocephalus . In this species, harems provide mating opportunities and so a male's ability to maintain a harem is likely to correlate with his fitness. We hypothesized that if T reflect a male's ability to withstand challenges from competitors, then T should be linked to successful harem maintenance. To test this, we temporarily removed males from their territories prior to and during the short mating period, recording their harem sizes both before removal and after reintroduction. Most males successfully reclaimed their territory and a harem, but during the mating period, males with higher T had harems closer to their original size, and males with lower T suffered reduction in harem size. Our findings highlight the role of T in harem maintenance in a major mammalian taxon with complex forms of social organization.

scholarly journals Serum Progesterone and Estradiol-17.BETA. Concentrations in Captive and Free-Ranging Adult Female Japanese Black Bears (Ursus thibetanus japonicus).

2000 ◽  
Vol 62 (4) ◽  
pp. 415-420 ◽  
Author(s):  
Miho SATO ◽  
Toshio TSUBOTA ◽  
Kaori YAMAMOTO ◽  
Takeshi KOMATSU ◽  
Yukihiko HASHIMOTO ◽  
...  
Keyword(s):  
Adult Female ◽  
Black Bears ◽  
Serum Progesterone ◽  
Ursus Thibetanus ◽  
Free Ranging

Plasma testosterone levels decrease after activation of skin immune system in a free-ranging mammal

2010 ◽  
Vol 168 (3) ◽  
pp. 466-473 ◽  
Author(s):  
Sabine Greiner ◽  
Volker Stefanski ◽  
Martin Dehnhard ◽  
Christian C. Voigt
Keyword(s):  
Immune System ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Skin Immune System ◽  
Free Ranging

INFLUENCE OF METYRAPONE ON PLASMA CONCENTRATIONS OF TESTOSTERONE AND ANDROSTENEDIONE IN MAN

1971 ◽  
Vol 68 (3) ◽  
pp. 576-584 ◽  
Author(s):  
K. O. Nilsson ◽  
B. Hökfelt
Keyword(s):  
Body Weight ◽  
Male Patient ◽  
Gradual Increase ◽  
Plasma Concentrations ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Basal Plasma ◽  
Normal Males ◽  
A Minor ◽  
Secondary Hypogonadism

ABSTRACT Metyrapone was administered either orally, 750 mg every four h, in a total of six doses, or intravenously 30 mg per kg body weight as a four h infusion. In three males with normal endocrine functions, metyrapone given orally or intravenously induced a fall in plasma testosterone and an elevation of androstenedione within 2–8 h. When metyrapone was administered to a patient given dexamethasone to suppress endogenous ACTH production, the androstenedione levels did not alter whereas the testosterone levels showed a slight, transient decrease. In two normal females metyrapone administration was followed by a marked increase in plasma androstenedione whereas testosterone showed only a minor, gradual increase. In one male patient with Addison's disease the basal plasma testosterone was normal whereas the level of androstenedione was low. Following metyrapone intravenously, there was a slight suppression of plasma testosterone but no change in the androstenedione concentration. In one patient with primary hypogonadism, two with secondary hypogonadism and two with Klinefelter's syndrome the plasma testosterone was low under basal conditions and did not change following metyrapone. Basal plasma androstenedione was within the range for normal males and increased markedly following metyrapone in all the cases.

Effects of oestradiol benzoate (OeB) and human chorionic gonadotrophin (hCG) on the testes and accessory sex glands of the rat

1981 ◽  
Vol 96 (2) ◽  
pp. 273-280 ◽  
Author(s):  
Mridula Chowdhury ◽  
Robert Tcholakian ◽  
Emil Steinberger
Keyword(s):  
Treated Group ◽  
Inhibitory Effect ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Control Group ◽  
Intact Male ◽  
Intact Control ◽  
Testosterone Levels ◽  
Oestradiol Benzoate ◽  
Direct Inhibitory Effect

Abstract. It has been suggested that treatment of intact male rats with oestradiol benzoate (OeB) causes an interference with testosterone (T) production by the testes by a direct inhibitory effect on steroidogenesis. To test this hypothesis, different doses (5, 10 or 25 IU) of hCG were administered concomitantly with 50 μg of OeB to adult intact or hypophysectomized male rats. The testicular and plasma testosterone, and serum hCG levels were determined. The sex accessory weights were recorded. In the intact OeB-treated group of animals, hCG stimulated both the secondary sex organs and plasma testosterone levels above the intact control group. However, in hypophysectomized animals, although plasma testosterone levels increased above that of intact controls, their secondary sex organ weights did not. Moreover, inspite of high circulating hCG levels, the testicular testosterone content and concentration remained suppressed in OeB-treated animals. The reason for such dichotomy of hCG action on OeB-treated animals is not clear at present.

Association Between Androgen Receptor Gene CAG Repeat Polymorphism and Plasma Testosterone Levels in Postmenopausal Women

2005 ◽  
Vol 12 (2) ◽  
pp. 135-141 ◽  
Author(s):  
Ilma Simoni Brum ◽  
Poli Mara Spritzer ◽  
Franyoise Paris ◽  
Maria Augusta Maturana ◽  
Franyoise Audran ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Postmenopausal Women ◽  
Receptor Gene ◽  
Androgen Receptor Gene ◽  
Cag Repeat ◽  
Plasma Testosterone ◽  
Repeat Polymorphism ◽  
Testosterone Levels
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