Relationship between testosterone binding globulin and the failure of androgens to suppress serum gonadotropin concentrations in long-term castrated adult male rhesus monkeys (Macaca mulatta)

Winters, Stephen J.; Troen, Philip; Plant, Tony M.

doi:10.1016/0022-4731(81)90055-8

Cited by 19 publications

(12 citation statements)

References 22 publications

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“…The levels are lower in males than in females. This fact raised the question of hormonal influence on the mSBP concentration, According to Heinrichs et al (1979) and Winters et al (1981), the mSBP level increases in castrated males, which suggests a negative androgenic influence. In Cynomolgus monkeys (Koritnik and Marschke, 1986), the samples from ovariectomized females failed to reveal a difference compared to cycling females; this suggests a minimal estrogenic influence.…”

Section: Discussionmentioning

confidence: 97%

“…Thus, the mSBP concentration has been widely studied in these species in order to establish the monkey as a valuable animal model for the study of the physiological role of SBP (Petra and Schiller, 1977;Winters et al, 1981;Stanczyk et al, 1985;Koritnik and Marschke, 1986). All of these determinations were usually performed by binding assay with radiolabeled steroid, and all of the reported data were directly related to the biological activity of SBP.…”

Section: Discussionmentioning

confidence: 99%

“…mulatta (Stanczyck et al, 1986) and in M. fasciculurk (Koritnik and Marschke, 1986), estrogens have a minimal influence. Testosterone implantation markedly reduces mSBP levels (Heinrichs et al, 1979;Burry et al, 1980;Winters et al, 1981). Decreasing SBP levels during pregnancy have been reported in M. nemestrinu (Schiller et al, 1978), M. muluttu (Stanczyk et al, 1986), and M .…”

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confidence: 93%

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Regulation of Plasma Sex-Steroid-Binding Protein in Adult Cynomolgus Monkeys (Macaca Fascicularis) during Different Reproductive States

Kottler¹,

Tardivel-Lacombe²,

Domingo³

et al. 1988

Biology of Reproduction

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Levels of the sex-steroid binding protein (mSBP) have been characterized in Cynomolgus monkeys, during different stages of reproduction and under hormonal treatments, by an immunoassay allowing a specific and accurate measurement of the protein itself. Using an antiserum specific for native human SBP, we have determined the mSBP level by electroimmunodiffusion. This method correlates closely with the binding capacity measured by a steady-state polyacrylamide electrophoresis. The levels are lower in males (M = 88 +/- 8.6 nmoles/1, n = 6) than in females in the follicular phase (M = 123 +/- 4.4 nmoles/1, n = 5, p less than 0.001) and in castrated males (M = 172 +/- 13.3 nmoles/1, n = 3, p less than 0.001). During gestation, the SBP level decreases (M = 69 +/- 16.3 nmoles/1, n = 7, in the latter part of pregnancy), but during lactation, it is similar to follicular values. Estrogen treatment fails to increase SBP levels in castrated animals, but the values are reduced by testosterone treatment. Since these results are different from those observed in women, we question the validity of using monkeys as models for understanding the mechanisms controlling the concentration of SBP in human blood.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 93%

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Regulation of Plasma Sex-Steroid-Binding Protein in Adult Cynomolgus Monkeys (Macaca Fascicularis) during Different Reproductive States

Kottler¹,

Tardivel-Lacombe²,

Domingo³

et al. 1988

Biology of Reproduction

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“…The changes in the dynamics of LH secretion after castration are attributed to removal of negative feedback signals normally imposed by gonadal steroids (Schanbacher, 1980a). Testosterone appears to be the steroid primarily responsible for regulating LH secretion in the ram (D'Occhio et al, 1982b); however, long-term castrated rams (Edgerton and Baile, 1977), bulls (D'Occhio et al, 1982a) and rhesus monkeys (Winters et al, 1981) show an insensitivity to androgen feedback. Estradiol, on the other hand, is effective in suppressing LH in long-term castrated rams (Schanbacher and Ford, 1977) and bulls (D'Occhio et al, 1982a This article is a U.S. government work, and is not subject to copyright in the United States.…”

Section: Introductionmentioning

confidence: 99%

Pulsatile Luteinizing Hormone Secretion in the Castrate Male Bovine: Effects of Testosterone or Estradiol Replacement Therapy1

Schanbacher¹,

D’Occhio²,

Gettys³

1983

Journal of Animal Science

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“…46, 57] and (ii) dur ing the nocturnal hours in intact male rhesus [3,21,45,49] and, consequently, whether these high levels of testosterone are crucial for the negative feedback control of LH. The success of these high testosterone levels in suppressing LH would certainly help to explain the failure of previous stud ies to suppress LH levels in castrated male rhesus monkeys using lower testosterone levels [47,51,68]. The relatively constant titres of testosterone maintained in the present study were as effective in suppressing LH concentrations as procedures replicating the nyctohemeral rhythms [1,3,57].…”

Section: Discussionmentioning

confidence: 60%

Serum and CSF Concentrations of Testosterone and LH Related to Negative Feedback in Male Rhesus Monkeys

Dubey¹,

Herbert²,

Abbott³

et al. 1984

Neuroendocrinology

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Testosterone and LH concentrations were studied in blood and cerebrospinal fluid (CSF) in 8 adult male rhesus monkeys. All males were initially intact and 7 were subsequently castrated and implanted with an ascending series of testosterone capsules. In 4 of the males, serum testosterone levels were significantly higher at 21.00 h than at 09.00 h when the monkeys were intact. Following castration of these 4 males, 4–10 testosterone capsules produced serum concentrations similar to those previously found at 09.00 h; levels equivalent to those at 21.00 h were attained with 12–14 capsules. The proportion of unbound testosterone in serum represented 2% of total serum concentrations, but increased to 4% at high serum concentrations (12–14 capsules). In contrast, the proportion of unbound testosterone in CSF represented 100% of CSF levels. The levels of testosterone in CSF remained at values equal to 2–3% of total serum concentrations throughout the study. The levels of unbound serum testosterone and testosterone levels in the CSF were similar throughout the study in 3 of the 4 monkeys. In the fourth animal, supraphysiological serum testosterone levels occurred with 12 and 14 implants, and, at this time, the level of testosterone in CSF was less than the concentrations of unbound testosterone in serum. Following an intravenous bolus injection of testosterone, the steroid rapidly entered CSF when either 6 or 14 capsules were in place. Although the clearance of testosterone was similar within either compartment during both treatments, the half-life of testosterone in CSF was significantly shorter than in serum at high serum concentrations (14 capsules). Serum and CSF LH levels rose rapidly after castration, reaching maximal levels 8–12 days later with CSF LH levels consistently representing 2–3% of serum concentrations. Post-castration LH concentrations did not change until nocturnal testosterone levels were reached (12–14 capsules), when LH levels were suppressed in both serum and CSF. Subsequent reduction of serum testosterone levels (to 6 capsules) maintained the low LH concentrations. Seemingly, high testosterone concentrations in either serum or CSF, equivalent to nocturnal levels in intact males, were required to initiate LH suppression, but not to maintain it.

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Relationship between testosterone binding globulin and the failure of androgens to suppress serum gonadotropin concentrations in long-term castrated adult male rhesus monkeys (Macaca mulatta)

Cited by 19 publications

References 22 publications

Regulation of Plasma Sex-Steroid-Binding Protein in Adult Cynomolgus Monkeys (Macaca Fascicularis) during Different Reproductive States

Regulation of Plasma Sex-Steroid-Binding Protein in Adult Cynomolgus Monkeys (Macaca Fascicularis) during Different Reproductive States

Pulsatile Luteinizing Hormone Secretion in the Castrate Male Bovine: Effects of Testosterone or Estradiol Replacement Therapy1

Serum and CSF Concentrations of Testosterone and LH Related to Negative Feedback in Male Rhesus Monkeys

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