The period of postpartum infertility in primiparous female primates is longer than the interval in multiparous females. First pregnancy and resultant lactation typically occur in female primates prior to the completion of the growth phase and therefore have implications for continued growth and subsequent reproductive capacity. Pregnancy and lactation produce specific changes in the neuroendocrine system controlling ovulation, and also increase the nutritional requirements of the female, both effects which may be exacerbated in young, sexually-mature females. We propose a series of longitudinal experiments using four groups of female rhesus monkeys to determine how age, parity and maternal nutritional status influence the duration and characteristics of postpartum infertility. Subjects will be studied in provisioned, outdoor housed social groups to assess how mother-infant interactions influence the lactational process. We will determine by measurement of body weight, percent body fat, and skeletal growth how age at first pregnancy and lactation influence the completion of the growth process. The studies will specify how first pregnancy and first lactation differentially influence the pattern of growth. A comparison of multiparous females to different-aged primaparous females during the lactational period will determine how age and parity affect patterns of 1) maternal care, 2) infant nursing behavior and physical growth, and 3) maternal endocrine status, measured by serum levels of prolactin, luteinizing hormone, follicle-stimulating hormone, and ovarian steroids. These analyses will elucidate how the duration of postpartum infertility in primiparous mothers is influenced by the nutritional costs of lactation, by infant nursing patterns, or by the interaction between these two variables. Finally, we will determine how parity and age influence the resumption of fertility and the capacity of females to conceive and maintain pregnancy. The characteristics of first lactation, including alterations in maternal nutritional status and basal insulin levels, will be related to the subsequent reproductive ability of the female. This project will further define how pregnancy and lactation influence the completion of growth and the parameters of subsequent reproductive activity in young primate mothers.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD018120-02
Application #
3315077
Study Section
Human Embryology and Development Subcommittee 2 (HED)
Project Start
1984-05-01
Project End
1987-04-30
Budget Start
1985-05-01
Budget End
1986-04-30
Support Year
2
Fiscal Year
1985
Total Cost
Indirect Cost
Name
Emory University
Department
Type
Primate Centers
DUNS #
042250712
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Wilson, M E (1993) Oestradiol negative feedback inhibition on LH secretion during lactation is prolonged in adolescent primiparous rhesus monkeys. J Endocrinol 136:127-36
Wilson, M E (1992) Primiparous rhesus monkey mothers are more sensitive to the nursing-induced inhibition of LH and ovarian steroid secretion. J Endocrinol 134:493-503
Wilson, M E; Gordon, T P; Chikazawa, K et al. (1991) Effects of growth hormone on neonatal growth in nursing rhesus monkeys. J Clin Endocrinol Metab 72:1302-7
Wilson, M E; Walker, M L; Pope, N S et al. (1988) Prolonged lactational infertility in adolescent rhesus monkeys. Biol Reprod 38:163-74
Pope, N S; Wilson, M E; Gordon, T P (1987) The effect of season on the induction of sexual behavior by estradiol in female rhesus monkeys. Biol Reprod 36:1047-54
Wilson, M E; Pope, N S; Gordon, T P (1987) Seasonal modulation of luteinizing-hormone secretion in female rhesus monkeys. Biol Reprod 36:975-84
Pope, N S; Gordon, T P; Wilson, M E (1986) Age, social rank and lactational status influence ovulatory patterns in seasonally breeding rhesus monkeys. Biol Reprod 35:353-9