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

Abstract

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.

Plasma insulin-like growth factor-I, testosterone and morphological changes in the growth of captive agile gibbons ( Hylobates agilis ) from birth to adolescence

“…This is because gibbons do not show such remarkable morphological changes with reproductive maturation like macaques or chimpanzees (e.g., swelling of sexual skin). Our previous study revealed a close functional relationship between insulin-like growth factor-1 (IGF-1) and skeletal growth in Japanese macaques (Macaca fuscata) (Suzuki et al 2000). We also confirmed that the adolescent phase of the macaque males begins in the summer at 3 years of age, as shown from the profiles of IGF-1 and testosterone secretion (Suzuki et al 2000).…”

“…Detailed procedures have been reported previously (Suzuki et al 2000). All samples were determined in duplicate.…”

“…These peaks are suggestive of the seasonality of IGF-1 secretion. In addition to the developmental increase, longitudinal data of plasma IGF-1 have shown seasonal fluctuation in adolescent male Japanese macaques (Suzuki et al 2000). Thus, additional research is necessary to determine the seasonality of plasma IGF-1 concentrations.…”

“…Our previous study revealed a close functional relationship between insulin-like growth factor-1 (IGF-1) and skeletal growth in Japanese macaques (Macaca fuscata) (Suzuki et al 2000). We also confirmed that the adolescent phase of the macaque males begins in the summer at 3 years of age, as shown from the profiles of IGF-1 and testosterone secretion (Suzuki et al 2000). Plasma IGF-1 has been identified as one important hormone that maintains somatic growth in primates (Copeland et al 1982(Copeland et al , 1984(Copeland et al , 1985Humbel 1984;Wilson et al 1984;Martin 1985;Wilson 1986).…”

Hormones and Human and Nonhuman Primate Growth

“…Experimental work in captive rhesus macaques demonstrates a seasonal infradian rhythmicity in GH and IGF-I secretion in individuals housed outdoors; compared to females living indoors, outdoor-living females are delayed in skeletal growth due to these endocrine differences [32]. In seasonally reproducing Japanese macaques (e.g., Macaca fuscata [33]), close associations between skeletal growth and body weight are seen in males, but not females. In female macaques, high-fat diets modify GH and IGF levels, apparently accelerating ovulation without a concomitant effect on somatic growth during puberty [34].…”