Leptin and thyroxine during sexual development in male monkeys: effect of neonatal gonadotropin-releasing hormone antagonist treatment and delayed puberty on the developmental pattern of leptin and thyroxine secretion

Mann, David R.; Akinbami, Mukaila A.; Gould, Kenneth G.; Castracane, V. Daniel

doi:10.1530/eje.0.1460891

Cited by 14 publications

(11 citation statements)

References 47 publications

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“…Nevertheless, in primates the prepubertal increase in leptin does not stimulate the liberation of GnRH [33, 34] and, therefore, does not participate in the onset of puberty [35,36,37]. In humans leptin also plays an important role, since the ontogenic signals of the hypothalamic-pituitary-gonadal axis in the monkey and in man seem to be qualitatively identical [33, 34].…”

Section: Discussionmentioning

confidence: 99%

Longitudinal Study of the Simultaneous Secretion of Melatonin and Leptin during Normal Puberty

Molina-Carballo

Fernández-Tardáguila²,

Uberos‐Fernández³

et al. 2007

Horm Res Paediatr

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Background/Aims: Pubertal changes are a consequence of the activation of the hypothalamic-pituitary-gonadal axis due to an increase in the frequency and magnitude of pulses of gonadotropin-releasing hormone (GnRH), which may depend on the intrinsic properties of the neurons of the hypothalamic arcuatus nucleus, or on the influence of neurotransmitters and/or neuromodulators. We evaluated the serum concentrations of melatonin and leptin in healthy prepubertal and adolescent subjects of both sexes, to define their participation at the initial stages and during the progression of pubertal development. Methods: 80 pediatric subjects (47 females and 33 males), aged 6–18 years, were divided into 2 groups, prepubertal (n = 25) and adolescent (n = 55), according to the absence or presence, respectively, of physical signs of pubertal development. The subjects were assessed on two occasions: at the time of their inclusion in the study, and 12–18 months later when the subject had advanced one pubertal stage according to the Tanner classification. Blood was obtained in fasting for clinical purposes and for the hormonal study. Melatonin and leptin were measured by radioimmunoanalysis. Results: As described previously, melatonin decreases at the onset of puberty and during pubertal development. Both the absolute melatonin value and the decrease between evaluations tended to be greater in females; the variations were correlated with neither an increase in body weight nor with the degree of pubertal development. The concentration of leptin increased in both sexes with the progression of puberty, this value being 40% greater in women, and correlated with the indicators of an increase in body volume and fat accumulation. Although its concentration remained stable between evaluations for both sexes, among the males the association between leptin and pubertal development took place at the start of the process, while for the females we observed a significant overall association between pubertal stage and leptin concentration, this association being stronger at more advanced Tanner stages. Neither at the onset of puberty nor during its course did we observe any significant relation between melatonin concentration and any of the Tanner stages, whether for males or for females. Neither was there any correlation between the absolute values or rates of modification of melatonin and leptin. Conclusion: According to the evolutionary dynamics of their respective concentrations, both initially and during pubertal progress, melatonin and leptin do not interact in the initiation or progression of human pubertal development, and do not seem to play a key role in this process.

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Section: Discussionmentioning

confidence: 99%

Longitudinal Study of the Simultaneous Secretion of Melatonin and Leptin during Normal Puberty

Molina-Carballo

Fernández-Tardáguila²,

Uberos‐Fernández³

et al. 2007

Horm Res Paediatr

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“…Although there were no observed changes in leptin levels prior to puberty, these data do not indicate whether differences in leptin levels between individuals account for some of the variation in the timing of puberty onset. In gonad-intact rhesus monkeys, leptin levels from 8–24 months and 26–50 months of age did not differ between males that reached puberty at 3.5 years of age and males that exhibited delayed puberty at 4.5 years of age, which suggests that variation in puberty timing is not influenced by leptin (Mann et al, 2002). Despite the relationship between body weight and puberty onset, the data indicate that leptin does not influence puberty onset in male rhesus macaques as leptin levels do not change around the time of puberty and differences in puberty timing are not the result of differences in leptin levels.…”

Section: Body Weight and Puberty Onsetmentioning

confidence: 95%

“…Intravenous GnRH administration increased LH levels comparably during both leptin or vehicle infusion, further supporting that exogenous leptin does not alter GnRH release or alter the timing of puberty onset (Barker-Gibb et al, 2002). Bimonthly endogenous leptin levels did not change during the year prior to puberty onset (26–38 months of age) or during puberty (39–50 months of age), and leptin levels remained constant even though increases in LH, T and testicular volume occurred between approximately 40–46 months of age in socially-housed male rhesus macaques living outdoors (Mann et al, 2000, 2002). Thus, there are no changes in endogenous leptin levels that seem to coincide with activation of the HPG axis and puberty onset.…”

Section: Body Weight and Puberty Onsetmentioning

confidence: 97%

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Environmental and social influences on neuroendocrine puberty and behavior in macaques and other nonhuman primates

Stephens

Wallen

2013

Hormones and Behavior

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Puberty is the developmental period when the hypothalamic-pituitary-gonadal (HPG) axis is activated, following a juvenile quiescent period, and reproductive capacity matures. Although pubertal events occur in a consistent sequence, there is considerable variation between individuals in the onset and timing of pubertal events, with puberty onset occurring earlier in girls than in boys. Evidence in humans demonstrates that social and environmental context influences the timing of puberty onset and may account for some of the observed variation. This review analyzes the nonhuman primate literature, focusing primarily on rhesus macaques (Macaca mulatta), to examine the social and environmental influences on puberty onset, how these factors influence puberty in males and females, and to review the relationship between puberty onset of adult neuroendocrine function and sexual behavior. Social and environmental factors influence the timing of puberty onset and pubertal events in nonhuman primates, as in humans, and the influences of these factors differ for males and females. In nonhuman primates, gonadal hormones are not required for sexual behavior, but modulate the frequency of occurrence of behavior, with social context influencing the relationship between gonadal hormones and sexual behavior. Thus, the onset of sexual behavior is independent of neuroendocrine changes at puberty; however, there are distinct behavioral changes that occur at puberty, which are modulated by social context. Puberty is possibly the developmental period when hormonal modulation of sexual behavior is organized, and thus, when social context interacts with hormonal state to strongly influence the expression of sexual behavior.

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“…Early studies showed that leptin accelerated puberty [22,48,49], suggesting that leptin might be a metabolic trigger for its time of onset. However, later studies did not report a good correlation between normal prepubertal serum leptin levels and the timing of puberty in normal rodents [50][51][52] or primates [53][54][55][56]. Therefore, Cheung et al [52], Urbanski [33], and Mann and Plant [32] suggested that leptin was not the trigger for puberty.…”

mentioning

confidence: 99%

Pituitary Leptin-A Paracrine Regulator of Gonadotropes: A Review

2011

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Leptin, a potent anorexigenic hormone secreted primarily by adipocytes, is known to be expressed in the anterior pituitary. Studies in our laboratory found leptin proteins and mRNA predominantly in somatotropes in normal male and cycling female rats. In contrast, leptin expression predominated in gonadotropes during pregnancy and lactation. Leptin expression varied with the cycle and was enhanced, in vitro by gonadotropin releasing hormone and Neuropeptide Y. In contrast, ghrelin inhibited pituitary leptin expression. Pituitary leptin in somatotropes or gonadotropes was reduced by nutritional deprivation for 24 h. However, growth hormone (GH), luteinizing hormone (LH) and pituitary leptin recovered if fasted animals were given glucose water. The glucose-mediated recovery suggests that the system is sensitive to changes in serum glucose. Somatotropes and gonadotropes also recovered if pituitary cells from fasted rats were stimulated in vitro with 1-100 pg/ml leptin. This in vitro leptin-mediated recovery suggests that leptin is important in the maintenance of somaotropes and gonadotropes. Collectively, the data suggest that pituitary leptin might serve as a "glucostat", sensing levels of serum glucose and reporting this nutritional state to somaotropes and gonadotropes in a paracrine manner. A decrease in pituitary leptin might signal nutritional deprivation to somatotropes and gonadotropes, lowering LH and GH production and allowing for conservation of resources. Lower GH would help conserve fat stores and lower LH would promote survival over reproduction.

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Leptin and thyroxine during sexual development in male monkeys: effect of neonatal gonadotropin-releasing hormone antagonist treatment and delayed puberty on the developmental pattern of leptin and thyroxine secretion

Cited by 14 publications

References 47 publications

Longitudinal Study of the Simultaneous Secretion of Melatonin and Leptin during Normal Puberty

Longitudinal Study of the Simultaneous Secretion of Melatonin and Leptin during Normal Puberty

Environmental and social influences on neuroendocrine puberty and behavior in macaques and other nonhuman primates

Pituitary Leptin-A Paracrine Regulator of Gonadotropes: A Review

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