Dietary influences on growth and sexual maturation in premenarchial rhesus monkeys

Schwartz, Susan M.; Wilson, Mark; Walker, Margaret L.; Collins, Delwood C.

doi:10.1016/0018-506x(88)90069-4

Cited by 58 publications

(21 citation statements)

References 48 publications

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“…Another study in rhesus macaques demonstrated that the first increase in plasma IGF-1 levels occurred in February at 2 years of age, and the level in April was nearly twice as high as in the previous May [13] or June [26]. The first ovulation occurred in the autumn of 2 years of age in female rhesus macaques [26]. This suggests that the rise in plasma IGF-1 levels occurs one year prior to the first ovulation in rhesus macaques.…”

Section: Figmentioning

confidence: 90%

“…His results indicate no significant difference between any groups, suggesting that plasma IGF-1 levels do not increase by 3 years of age in rhesus macaques. Another study in rhesus macaques demonstrated that the first increase in plasma IGF-1 levels occurred in February at 2 years of age, and the level in April was nearly twice as high as in the previous May [13] or June [26]. The first ovulation occurred in the autumn of 2 years of age in female rhesus macaques [26].…”

Section: Figmentioning

confidence: 99%

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Time Series Analysis of Plasma Insulin-like Growth Factor-I and Gonadal Steroids in Adolescent lapanese Macaques (Macaca fuscata).

Suzuki

Ohkura

Hayakawa

et al. 2000

Journal of Reproduction and Development

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Abstract. The present study was conducted to reveal the developmental changes in plasma IGF-1 concentrations in male and female Japanese macaques by a long-term longitudinal method from 3 to 6 years of age. The sexual maturation and reproductive seasonality in both genders were determined by plasma profiles of gonadal steroids, such as testosterone and progesterone. Since Japanese macaques have been known to have a rather unique characteristic of clear seasonality in reproduction, the present study introduced a time series analysis to extract two factors -seasonal and age changes-from the changes in plasma hormonal levels. Plasma IGF-1 concentrations showed seasonal and age-development changes in males. Plasma IGF-1 levels were high in summer and low in spring. Age-dependent changes would be superimposed on the seasonal change, because the IGF-1 levels of 4-and 5-year-old males were nearly twice as high as those of 3-year-old males in every corresponding season. Females, on the other hand, did not have clear age-dependent changes in the plasma IGF-1 level. The time series analysis suggests a close functional relationship between IGF-1 and testosterone secretion in regulating skeletal growth and seasonal changes in body weight.

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Section: Figmentioning

confidence: 90%

Section: Figmentioning

confidence: 99%

Time Series Analysis of Plasma Insulin-like Growth Factor-I and Gonadal Steroids in Adolescent lapanese Macaques (Macaca fuscata).

Suzuki

Ohkura

Hayakawa

et al. 2000

Journal of Reproduction and Development

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“…When females are in a state of positive energy balance-that is, they are consuming or have stored more calories than they are using-reproduction is maintained (Schneider & Wade, 2000). Evidence that this is important in rhesus monkeys comes from studies showing that adolescent rhesus monkeys fed a high fat diet, which markedly increased caloric flux, ovulated at an earlier age than did females consuming a normal fat diet (Schwartz, Wilson, Walker, & Collins, 1988). In addition, females who ovulated early with respect to their peers had higher body weights at the onset of puberty (Zehr, 2002).…”

Section: Effects Of Social Rank On Pubertal Developmentmentioning

confidence: 99%

Hormones and history: The evolution and development of primate female sexuality

Wallen¹,

Zehr

2004

Journal of Sex Research

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Sexual behavior is required for reproduction in internally fertilizing species but poses significant social and physical risks. Females in many nonprimate species have evolved physical and behavioral mechanisms restricting sexual behavior to when females are fertile. The same hormones producing female fertility also control these mechanisms, assuring that sex only occurs when reproduction is possible. In contrast to nonprimate mammals, hormones do not regulate the capacity to engage in sex in female anthropoid primates, uncoupling fertility and the physical capacity to mate. Instead, in primates, sexual motivation has become the primary coordinator between sexual behavior and fertility. This dependence upon psychological mechanisms to coordinate physiology with behavior is possibly unique to primates, including humans, and allows a variety of nonphysiological influences, particularly social context, to regulate sexual behavior. The independence between hormonal state and sexual behavior allows sex to be used for social purposes. This complex regulation of primate sexuality develops during adolescence, where female monkeys show both hormonally influenced sexual motivation and socially modulated sexual behavior. We present findings from rhesus monkeys illustrating how social context and hormonal state interact to modulate adolescent and adult sexuality. It is argued that this flexibility in sexual behavior, combined with a tight regulation of sexual motivational systems by reproductive hormones, allows sexual behavior to be used for nonreproductive purposes while still assuring its occurrence during periods of female fertility. The evolutionary pressures that produced such flexibility in sexual behavior remain puzzling, but may reflect the importance of sexuality to primate social attraction and cohesion.With respect to sexuality, I have often speculated on it, and have always concluded that we are too ignorant to speculate: no physiologist can conjecture why the two elements go to form a new being, and more than that, why nature strives at uniting the two elements from two individuals. (Darwin, 1861, in Darwin, 1903 In the preceding quote, Darwin's reference to "sexuality" was in the sense of sexual reproduction. We are, however, similarly ignorant about the behavior that accompanies sexual reproduction, the now conventional use of the term sexuality. What are the causes for engaging in sexual behavior? Why does sexual behavior vary across development and across species? What brings two individuals together so that their gametes can combine? We have partial answers to some of these questions, while answers for others remain elusive. However much of what is understood reflects the reality that sex is expensive, dangerous, and time consuming.

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“…Schwaltz et al, 1988;Surbey, 1990;Bercovitch & Strum, 1993;Bercovitch, 2000;. Early maternal influences on growth and individual success as a juvenile thus are factors which may pace processes in adolescence.…”

Section: Sexual Selection and Adolescencementioning

confidence: 99%

Development and sexual selection in primates

Setchell

Lee

2004

Sexual Selection in Primates

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Dietary influences on growth and sexual maturation in premenarchial rhesus monkeys

Cited by 58 publications

References 48 publications

Time Series Analysis of Plasma Insulin-like Growth Factor-I and Gonadal Steroids in Adolescent lapanese Macaques (Macaca fuscata).

Time Series Analysis of Plasma Insulin-like Growth Factor-I and Gonadal Steroids in Adolescent lapanese Macaques (Macaca fuscata).

Hormones and history: The evolution and development of primate female sexuality

Development and sexual selection in primates

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