Seasonal variations in thyroxine and testosterone levels in relation to the moult in the adult male mink (Mustela vison Peale and Beauvois)

1981 ◽  
Vol 59 (6) ◽  
pp. 1062-1066 ◽  
Author(s):  
L. Boissin-Agasse ◽  
D. Maurel ◽  
J. Boissin
Keyword(s):  
Seasonal Change ◽  
Adult Male ◽  
Seasonal Variations ◽  
Environmental Temperature ◽  
Plasma Testosterone ◽  
Natural Light ◽  
Annual Maximum ◽  
Molting Cycle ◽  
Testosterone Levels ◽  
Ad Libitum

Plasma thyroxine (T4) and testosterone concentrations were measured in adult male mink maintained outdoors under natural light and fed ad libitum the whole year round. Plasma T4 concentrations presented a biphasic seasonal change, the highest values occurring in the spring and autumn months and the lowest values in the winter months. The plasma testosterone cycle showed an annual maximum in January–February. The possibility of testis–thyroid interactions is discussed. The changes observed are correlated with environmental temperature, photoperiod, and molting cycle.

scholarly journals Peripheral Administration of RF9 Does Not Affect Hypothalamic-PituitaryGonadal Axis in Normal Fed Adult Male Macaque

2020 ◽  
pp. 1-5
Author(s):  
Aalia Batool ◽  
Madiha Wazir ◽  
Rahim Ullah ◽  
Aalia Batool ◽  
Rabia Naz ◽  
...  
Keyword(s):  
Adult Male ◽  
Normal Saline ◽  
Time Windows ◽  
Treated Group ◽  
Plasma Testosterone ◽  
Control Group ◽  
Hpg Axis ◽  
Testosterone Levels ◽  
Physiological Conditions ◽  
Short Time

Stress represses hypothalamic-pituitary-gonadal axis (HPG-axis) but RF9, a synthetic peptide, rescues such repression. To assess the role of RF9 in regulating HPG-axis under normal physiological conditions in higher primates, RF9 was administered to intact adult male rhesus monkeys and response of the HPG-axis was examined by measuring plasma testosterone as an end parameter of the axis. Control group (n=4) received normal saline whereas the treated group (n=4) received RF9. On the first day of experiment, four bolus injections of normal saline (1ml/animal) were administered intravenously at 2-hr interval to the control monkeys. Similarly, on the second day of experiment, treated group received four iv bolus injections of RF9 (0.1mg/kg BW) at 2-hr interval. Serial blood samples were collected at 20 min interval during a 6-hr period which started just after first saline/RF9 injection. Plasma testosterone levels were measured by using a specific EIA. Overall means of plasma testosterone levels and plasma testosterone area under curve (AUC) and overall mean testosterone and mean testosterone AUC in short time windows following each injection of RF9 and saline were comparable between the groups. Our results demonstrate that RF9 has no role in regulating HPG-axis under normal physiological conditions in adult male monkeys.

Fluctuations in Plasma Testosterone Levels in Adult Male Rats and Mice

Endocrinology ◽  
1973 ◽  
Vol 92 (4) ◽  
pp. 1223-1228 ◽  
Author(s):  
A. BARTKE ◽  
R.E. STEELE ◽  
N. MUSTO ◽  
B.V. CALDWELL
Keyword(s):  
Adult Male ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Rats And Mice

EFFECTS OF FOLLICLE-STIMULATING HORMONE AND LUTEINIZING HORMONE ON PLASMA TESTOSTERONE LEVELS IN HYPOPHYSECTOMIZED AND IN INTACT IMMATURE AND ADULT MALE RATS

1974 ◽  
Vol 61 (2) ◽  
pp. 193-198 ◽  
Author(s):  
S. EL SAFOURY ◽  
A. BARTKE
Keyword(s):  
Luteinizing Hormone ◽  
Adult Male ◽  
Follicle Stimulating Hormone ◽  
Seminal Vesicles ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Adult Rats ◽  
Testosterone Levels ◽  
Hypophysectomized Rats ◽  
Stimulating Hormone

SUMMARY The effects of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) on plasma testosterone levels were examined in hypophysectomized and in intact immature and adult male rats. The animals were injected with saline, LH, FSH, or both gonadotrophins twice daily for 3·5 days and were killed 3 h after the last injection. Plasma testosterone levels were measured by radioimmunoassay. In immature hypophysectomized rats, plasma testosterone levels were not changed by treatment with LH, FSH or LH plus FSH. The weight of the testes and of the seminal vesicles was increased only in animals injected with both LH and FSH. In adult hypophysectomized rats, LH caused the expected increase in plasma testosterone levels, while FSH injected alone had no effect. Plasma testosterone levels in rats treated with 5 μg LH and 20 μg FSH were significantly greater than those in animals given 5 μg LH alone. However, the same dose of FSH did not potentiate the action of 25 μg LH on plasma testosterone levels. In adult hypophysectomized rats the weight of testes was not affected by any of the treatments. The weight of the seminal vesicles was increased by the higher dose of LH and addition of FSH caused no further increase. In intact immature and adult rats plasma testosterone levels and the weight of testes were not changed by any of the treatments. Seminal vesicle weight was increased only in adult rats treated with the higher dose of LH together with FSH. The results demonstrate that FSH potentiates the action of low doses of LH on plasma testosterone levels in adult hypophysectomized rats and suggest that FSH may be involved in the regulation of androgen secretion by the rat testis.

scholarly journals RF9 Rescues Cortisol-Induced Repression of Testosterone Levels in Adult Male Macaques

2021 ◽  
Vol 12 ◽  
Author(s):  
Rahim Ullah ◽  
Rabia Naz ◽  
Aalia Batool ◽  
Madiha Wazir ◽  
Tanzil Ur Rahman ◽  
...  
Keyword(s):  
Adult Male ◽  
Plasma Cortisol ◽  
Sodium Succinate ◽  
Plasma Testosterone ◽  
Hpg Axis ◽  
Testosterone Levels ◽  
Potent Agonist ◽  
Single Blood Sample ◽  
Male Rhesus ◽  
Hydrocortisone Treatment

Cortisol inhibits hypothalamic-pituitary-gonadal (HPG) axis whereas RF9, a potent agonist of kisspeptin receptor (GPR54) activates HPG-axis during fasting-induced stress and under normal physiological conditions. However, the effect of RF9 on the cortisol-induced repressed HPG-axis is not studied yet. This study investigated whether exogenous cortisol-induced repression of the HPG-axis can be rescued by RF9. Six intact adult male rhesus monkeys (Macaca mulatta) habituated to chair-restraint were administered hydrocortisone sodium succinate at a rate of 20 mg/kg of body weight (BW) per day for 12 days. Single blood sample was taken by venipuncture from each animal on alternate days for hormones analyses. On experimental day 12, hydrocortisone treated monkeys received a single intravenous bolus of RF9 (n = 3) and vehicle (n = 3). The animals were bled for a period of 4 h at 60 min intervals from an indwelling cannula in the saphenous vein. RF9 was administered intravenously at the dose of 0.1 mg/kg BW immediately after taking 0 min sample. Plasma cortisol and testosterone concentrations were measured by using specific enzyme immunoassays. Hydrocortisone treatment increased plasma cortisol levels (P ≤ 0.0001) and decreased plasma testosterone (P ≤ 0.0127) levels. Interestingly, compared to vehicle, RF9 treatment significantly increased plasma testosterone levels at 120 min (P ≤ 0.0037), 180 min (P ≤ 0.0016), and 240 min (P ≤ 0.0001) intervals in the hydrocortisone treated monkeys. From these results, we concluded that RF9 administration relieves the suppressed HPG-axis in term of plasma testosterone levels in the cortisol treated monkeys.

Cycles annuels de la testostéronémie et de la thyroxinémie chez Vipera berus L. (Reptilia: Viperidae) en relation avec le cycle sexuel et l'hivernage

1988 ◽  
Vol 9 (1) ◽  
pp. 33-42 ◽  
Author(s):  
François Fleury ◽  
Guy Naulleau
Keyword(s):  
Seasonal Variations ◽  
Secondary Peak ◽  
Plasma Testosterone ◽  
Maximal Concentration ◽  
Mating Period ◽  
Blood Samples ◽  
Vipera Berus ◽  
Testosterone Levels

AbstractBlood samples were taken in Vipera berus during a five year period. Changes in plasma thyroxine and testosterone levels were examined. Plasma testosterone levels show a marked profile. Highest levels are observed a few weeks after the emergence of hibernation from the end of March till the end of April. These values coincide with the mating period and spring spermiogenesis. Plasma thyroxine levels show also seasonal variations. Low values are observed in winter. Plasma thyroxine levels increase in spring and reach a maximal concentration shortly after the peak of plasma testosterone. A secondary peak is observed at the end of summer.

Semen parameters, fertility and testosterone levels in male rats exposed prenatally to betamethasone

2009 ◽  
Vol 21 (5) ◽  
pp. 634 ◽  
Author(s):  
Renata C. Piffer ◽  
Patrícia C. Garcia ◽  
Daniela C. C. Gerardin ◽  
Wilma G. Kempinas ◽  
Oduvaldo C. M. Pereira
Keyword(s):  
Adult Male ◽  
Sperm Quality ◽  
Male Offspring ◽  
Male Rats ◽  
Semen Parameters ◽  
Plasma Testosterone ◽  
Control Group ◽  
Long Term Effects ◽  
Testosterone Levels

The present study investigated the long-term effects of prenatal betamethasone exposure on sperm quality and count, fertility and plasma testosterone levels in adult male rats. Pregnant rats received 0.1 mg kg–1 betamethasone on Days 12, 13, 18 and 19 of pregnancy. This treatment impaired sperm quality, sperm production, fertility and plasma testosterone levels in adult male offspring compared to the control group. Thus, the results of the present study indicate that the long-term effects of prenatal betamethasone exposure may be deleterious to offspring. The consequent decrease in testosterone production during adulthood, in association with damaged semen parameters, may explain for the observed decrease in the capacity of adult male offspring to themselves generate viable descendants.

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