# NEONATAL TESTOSTERONE AND SEXUAL DEVELOPMENT

> **NIH NIH R01** · MOREHOUSE SCHOOL OF MEDICINE · 1994 · $180,130

## Abstract

We have evidence suggesting that neonatal activation of the pituitary-
testicular axis is a critical event in the process of sexual and behavioral
maturation in male primates.  Monkeys treated as neonates with a
gonadotropin-releasing hormone (GnRH)-agonist to suppress testicular
function exhibited differences in social behavior during the second year of
life, a delay or retardation of testicular development during the
peripubertal period and reduced male mountings during the non-breeding
season of their third year of life.  The proposed study is an effort to
expand our understanding of the importance of neonatal testosterone as an
organizational influence on sexual and behavioral processes in male
primates.  There are two components to this proposal:  an adult component
involving 5-year-old male monkeys treated as neonates with a GnRH-agonist
and an infant component involving the development of an additional cohort
of neonatal hypogonadotropic-hypogonadal animals using a potent GnRH-
antagonist.  With the adult component, we will determine whether the
deleterious effects of suppressing neonatal pituitary-testicular function
on sexual and aggressive behavior under conditions of high and low
intermale competition are altered by neonatal treatment with a GnRH-
analogue.  Efforts will be made to define the site(s) (hypothalamus,
pituitary or testis) of the physiological defect and determine whether the
FSH-inhibin negative feedback loop is functionally normal in GnRH-agonist-
treated monkeys.  We will also perform a detailed evaluation of the
fertility of these animals.  In the infant component, we will attempt to
confirm the effect of blocking neonatal activation of the pituitary-
testicular on sexual maturation using a GnRH-antagonist.  The importance of
neonatal testosterone in this process will be assessed by treating one
group of infants simultaneously with the GnRH-antagonist and testosterone.
The effect of treatment on the developmental pattern of pituitary and
gonadal hormone secretion, on growth and maturation of the skeletal system
and on sexual maturation will be determined.  The development of male
typical behavior and adult sexual behavior will be compared between animals
treated with the GnRH-antagonist alone or in combination with testosterone
therapy.  The proposed study will increase our understanding of
developmental mechanisms that govern sexual and behavioral development in
male primates and the role that neonatal testosterone plays in this
process.

## Key facts

- **NIH application ID:** 2199933
- **Project number:** 5R01HD026423-05
- **Recipient organization:** MOREHOUSE SCHOOL OF MEDICINE
- **SAM.gov UEI:** X5S7PNXMJMC7
- **Principal Investigator:** DAVID R MANN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $180,130
- **Award type:** 5
- **Project period:** 1989-12-01 → 1995-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2199933

## Citation

> US National Institutes of Health, RePORTER application 2199933, NEONATAL TESTOSTERONE AND SEXUAL DEVELOPMENT (5R01HD026423-05). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2199933. Licensed CC0.

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