Plasma Testosterone Levels in the Male Rhesus: Influences of Sexual and Social Stimuli

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.

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DIURNAL CHANGES IN PLASMA TESTOSTERONE AND STUDIES ON PLASMA CORTICOSTEROIDS IN NON-ANAESTHETIZED MALE RHESUS MONKEYS (MACACA MULATTA)

Journal of Endocrinology ◽

10.1677/joe.0.0630325 ◽

1974 ◽

Vol 63 (2) ◽

pp. 325-335 ◽

Cited By ~ 43

Author(s):

R. P. MICHAEL ◽

K. D. R. SETCHELL ◽

T. M. PLANT

Keyword(s):

Rhesus Monkeys ◽

Plasma Testosterone ◽

Diurnal Changes ◽

Intact Male ◽

Testosterone Levels ◽

Adrenocortical Activity ◽

Peripheral Plasma ◽

Basal Plasma ◽

Competitive Protein Binding ◽

Male Rhesus

SUMMARY The assays of testosterone and corticosteroids in plasma from adult male rhesus monkeys using competitive protein-binding and radioimmunoassay techniques are described. The radioimmunoassay for testosterone was conducted without chromatography and, therefore, additionally estimated 17β-hydroxy-5α-androstan-3-one (dihydrotestosterone). Levels of testosterone in the peripheral plasma of 14 intact male rhesus monkeys showed marked fluctuations over a period of 24 h. Concentrations of testosterone at 22.00 h (1776 ± 814 ( ± s.d.) ng/100 ml) were approximately double those at 08.00 h (858 ± 407 ng/100 ml), 12.00 h (898 ± 316 ng/100 ml) and 16.00 h (784 ± 530 ng/100 ml). Castration resulted in low plasma testosterone levels (85 ± 29 ng/100 ml), and the increases at 22.00 h were no longer observed. In intact males, the 'basal' plasma corticosteroidlevel(08.00 h) was 22·4 ± 6·0 μg/100 ml. Administration of synthetic corticotrophin raised plasma corticosteroid levels without changing plasma testosterone concentration. Because plasma testosterone levels were not related to changes in adrenocortical activity, the noctural rises appear to be due to changes in testicular secretion.

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DIURNAL VARIATIONS IN PLASMA TESTOSTERONE LEVELS OF ADULT MALE RHESUS MONKEYS

Acta Endocrinologica ◽

10.1530/acta.0.067s069 ◽

1971 ◽

Vol 68 (1_Supplb) ◽

pp. S69 ◽

Cited By ~ 4

Author(s):

T. M. Plant ◽

Richard P. Michael

Keyword(s):

Adult Male ◽

Rhesus Monkeys ◽

Diurnal Variations ◽

Plasma Testosterone ◽

Testosterone Levels ◽

Male Rhesus

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

Acta Endocrinologica ◽

10.1530/acta.0.0680576 ◽

1971 ◽

Vol 68 (3) ◽

pp. 576-584 ◽

Cited By ~ 5

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.

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

Acta Endocrinologica ◽

10.1530/acta.0.0960273 ◽

1981 ◽

Vol 96 (2) ◽

pp. 273-280 ◽

Cited By ~ 1

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.

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The Immediate Effect of HCG Upon Plasma Testosterone Levels in the Bull

Acta Veterinaria Scandinavica ◽

10.1186/bf03548665 ◽

1981 ◽

Vol 22 (3-4) ◽

pp. 403-408 ◽

Cited By ~ 1

Author(s):

A. Sundby

Keyword(s):

Plasma Testosterone ◽

Testosterone Levels

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

Journal of the Society for Gynecologic Investigation ◽

10.1016/j.jsgi.2004.11.003 ◽

2005 ◽

Vol 12 (2) ◽

pp. 135-141 ◽

Cited By ~ 29

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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Lymphocyte subset distribution and natural killer cell activity in men with idiopathic hypogonadotropic hypogonadism

Acta Endocrinologica ◽

10.1530/acta.0.1240399 ◽

1991 ◽

Vol 124 (4) ◽

pp. 399-404 ◽

Cited By ~ 10

Author(s):

Wieland Kiess ◽

Linda L. Liu ◽

Nicholas R. Hall

Keyword(s):

Natural Killer Cell ◽

Natural Killer ◽

Natural Killer Cell Activity ◽

Hypogonadotropic Hypogonadism ◽

Killer Cell ◽

Cell Activity ◽

Hormonal Treatment ◽

Plasma Testosterone ◽

Idiopathic Hypogonadotropic Hypogonadism ◽

Testosterone Levels

Abstract. Sex-related differences in immune responsiveness are mediated at least in part by sex steroid hormones. Lymphocyte subset distribution in peripheral blood and natural killer cell function both have been reported to be under hormonal control. In order to gain more insight into sex steroid hormone action on the immune system, we have measured the lymphocyte subset distribution and natural killer cell activity in 18 men with idiopathic hypogonadotropic hypogonadism before treatment, and after hormonal treatment had normalized plasma testosterone levels. In untreated patients, the mean plasma testosterone concentrations were significantly lower than those in the treated men (3.0 ± 0.5 nmol/l vs 16 ± 1.7 nmol/l, p < 0.001). The percentage of peripheral CD3+ lymphocytes, CD8+ cells, the CD4+/CD8+ ratio, and the natural killer cell activity of peripheral mononuclear cells measured in a 51Cr release assay against target K 562 cells did not differ between patients with idiopathic hypogonadotropic hypogonadism and healthy adults, and most importantly, did not change during hormonal treatment which normalized plasma testosterone levels in the patients. In contrast, the percentage of peripheral CD4+ cells was significantly higher in untreated patients compared with normal adult subjects or patients with idiopathic hypogonadotropic hypogonadism after hormonal treatment that resulted in normal plasma testosterone levels (53 ± 2 vs 47 ± 2, p < 0.05). It should be noted that the percentage of peripheral CD 16+ cells was significantly lower in untreated men with low plasma testosterone levels than in normal controls. The percentage of CD16+ cells in peripheral venous blood rose significantly after hormonal treatment restored plasma testosterone levels to normal (6 ± 1 vs 11 ± 1, p < 0.001). In addition, the percentage of peripheral CD16+ cells correlated significantly with the plasma testosterone levels measured in men with idiopathic hypogonadotropic hypogonadism (r = 0.534, p < 0.001). In conclusion, both the percentage of peripheral CD4+ cells (T-helper lymphocytes) and peripheral CD16+ cells (non-T-non-B cells) are related to the plasma testosterone levels in men with idiopathic hypogonadotropic hypogonadism. These data suggest that in vivo human immune cells are under the regulatory influence of endogenous sex steroids.

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