Seasonal variation in the plasma testosterone concentration of reindeer and caribou

1973 ◽  
Vol 51 (6) ◽  
pp. 651-658 ◽  
Author(s):  
P. E. Whitehead ◽  
E. H. McEwan
Keyword(s):  
Seasonal Variation ◽  
Growth Pattern ◽  
Seasonal Changes ◽  
Seasonal Pattern ◽  
Plasma Testosterone ◽  
Endocrine Glands ◽  
Testosterone Concentration ◽  
Testosterone Levels ◽  
Rhythmic Growth ◽  
Two Hybrid

Plasma testosterone levels of reindeer increased from 1 ng/cm3 in August to 30–60 ng/cm3 in mid-September. By late October, when rutting activity had almost ceased, the testosterone concentration had declined to barely detectable levels. The seasonal pattern exhibited by caribou was similar except the peak levels associated with rutting occurred about 1 month later than reindeer. The seasonal changes in plasma testosterone levels of two hybrid calves were studied. Peak testosterone levels of 5 and 3.8 ng/cm3 were attained in late October.The influence of the endocrine glands on antler renewal and casting, and the rhythmic growth pattern exhibited by caribou and reindeer are discussed.

Seasonal changes in plasma testosterone concentration and mating activity in Border Leicester, Poll Dorset, Romney and Suffolk rams

1983 ◽  
Vol 23 (122) ◽  
pp. 248 ◽  
Author(s):  
MJ D'Occhio ◽  
DE Brooks
Keyword(s):  
Seasonal Changes ◽  
Extended Period ◽  
Field Conditions ◽  
Plasma Testosterone ◽  
Real Relationship ◽  
Mating Activity ◽  
Testosterone Concentration ◽  
Testosterone Levels ◽  
Seasonal Peak ◽  
Precise Time

Seasonal changes in the plasma testosterone profile and mating activity were compared for Border Leicester, Poll Dorset, Romney and Suffolk rams (three of each breed) maintained under field conditions at latitude 35�S. Border Leicester, Romney and Suffolk showed maximum testosterone levels from February to May. Peak mating activity occurred from March to August, but the precise time and duration of the peak differed between the three breeds. A correlation (r = 0.65, P<0 .05) existed between seasonal changes in plasma testosterone and mating activity in Border Leicester but not in Romney or Suffolk. However, in all three breeds, peak testosterone levels preceded peak mating activity by 1-2 months. Poll Dorset rams showed an extended period of high testosterone levels from August to March but no seasonal peak in mating activity. There was no real relationship, in any breed, between plasma testosterone concentration and mating activity for individual rams within any month.

PLASMA TESTOSTERONE AND SHELL QUALITY

1989 ◽  
Vol 69 (4) ◽  
pp. 1107-1109
Author(s):  
S. LEESON ◽  
C. D. BENNETT ◽  
L. J. CASTON ◽  
C. E. ANDERSON-LANGMUIR ◽  
R. J. ETCHES
Keyword(s):  
Key Words ◽  
Testosterone Level ◽  
Plasma Testosterone ◽  
Production Cycle ◽  
Testosterone Concentration ◽  
Shell Quality ◽  
Testosterone Levels ◽  
Commercial Strain ◽  
Eggshell Quality ◽  
Key Words Testosterone

Plasma testosterone levels were measured in commercial strain Leghorn pullets from 16 to 80 wk of age. Testosterone level was high just prior to first egg, but subsequently declined and stayed at a constant level through the production cycle. There was no relationship between testosterone concentration and eggshell quality (P > 0.05). Key words: Testosterone, shell quality

Seasonal variation in plasma testosterone and the testis in captive male dingoes, Canis familiaries dingo

1979 ◽  
Vol 27 (6) ◽  
pp. 939 ◽  
Author(s):  
PC Catling
Keyword(s):  
Seasonal Variation ◽  
Breeding Season ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Central Australia ◽  
Eastern Highlands

Eastern Highlands and Central Australian dingoes housed in Canberra do not have a testicular cycle. They are spermatogenically active and capable of mating with oestrous females and fathering young all year. They do exhibit a breeding season (April-June) but this is entirely governed by the female. During the breeding season testosterone levels rise; this is thought to be influenced by the presence of an oestrous female and copulation. There are indications that captive dingoes in Central Australia may have a testicular cycle. Colony dingoes showed little interest in and do not mate with an oestrous domestic female at times other than January-July. They also become almost aspermous outside the breeding season. In contrast, Central Australian dingoes housed in Canberra are spermatogenically active and capable of successful matings all year.

scholarly journals Seasonal variation of plasma testosterone levels in Algerian male Arabia goats

2013 ◽  
Vol 12 (48) ◽  
pp. 6785-6790
Author(s):  
Amrane A. Ait ◽  
S. M. Hammoudi ◽  
B. T. Belhamiti ◽  
S. M. A. Selles ◽  
A. R. Benia ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Plasma Testosterone ◽  
Testosterone Levels

EFFECTS OF AN INTRAVENOUS INJECTION OF TETRACOSACTID ON PLASMA CORTICOSTEROID AND TESTOSTERONE LEVELS IN UNSTRESSED MALE RABBITS

1979 ◽  
Vol 91 (3) ◽  
pp. 511-518 ◽  
Author(s):  
K. W. Faulborn ◽  
M. Fenske ◽  
L. Pitzel ◽  
A. König
Keyword(s):  
Body Weight ◽  
Intravenous Injection ◽  
Plasma Levels ◽  
Plasma Testosterone ◽  
Rapid Rise ◽  
Testosterone Concentration ◽  
Testosterone Levels ◽  
Blood Withdrawal ◽  
Basal Plasma ◽  
Pre Treatment

ABSTRACT Administration of tetracosactid into male rabbits, fitted with permanently indwelling jugular catheters, resulted in a rapid rise of plasma corticosteroids and plasma testosterone. Corticosteroid concentrations were significantly elevated at 40 and 60 min and testosterone concentrations 20 min after the iv injection of tetracosactid (2.5, 5.0, and 10.0 μg/kg body weight), in comparison to pre-treatment levels. Corticosteroid values in plasma were elevated as long as 120 min after tetracosactid injection. In contrast, testosterone levels were lower at 60–120 min after tetracosactid injection than corresponding pre-treatment values. However, these differences were not significant. At the doses used no tetracosactiddose-dependent corticosteroid or testosterone release could be found; apparently, testosterone release is only dependent upon basal plasma levels but not upon the dose of tetracosactid applied. From these studies it is concluded that tetracosactid may bring about an increase or decrease of testosterone concentration in plasma in the buck depending upon the length of time elapsing between injection of tetracosactid and blood withdrawal.

Seasonal testosterone levels, testosterone clearance, and testicular weights in male domestic cats

1985 ◽  
Vol 63 (6) ◽  
pp. 1285-1287 ◽  
Author(s):  
Jay F. Kirkpatrick
Keyword(s):  
Correlation Coefficient ◽  
Half Life ◽  
Seasonal Pattern ◽  
Plasma Testosterone ◽  
Seminiferous Tubules ◽  
Domestic Cats ◽  
Clearance Rates ◽  
Photoperiodic Control ◽  
Testosterone Levels ◽  
Four Seasons

Concentrations of plasma testosterone, testosterone clearance rates from plasma, and testicular weights were measured in domestic tomcats during March, June, September, and December. Testicular weights showed a seasonal pattern, with significantly higher values in June than in December and March; however, sperm were present in the seminiferous tubules during all four seasons. The correlation coefficient between seasonal testicular weights and plasma testosterone concentrations was r = 0.929 (P < 0.05). Testosterone clearance rates indicated a half-life of 9.2 ± 2.3 min with no significant differences during the 4 months studied. These data suggest that tomcats are not seasonal breeders, but that there is a positive photoperiodic control of testicular weights. Fluctuations in plasma testosterone concentrations are moderated by testosterone production rather than by changes in testosterone clearance.

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