Dynamic Changes of RFRP3/GPR147 in the Precocious Puberty Model Female Rats
Authors: Sun Wen , Li Suhuan , Tian Zhanzhuang , Shi Yumin , Yu Jian , Sun Yanyan , Wang Yonghong 
Published: November 2019

Background:
Pubertal development is a complex physiological process
regulated by the neuroendocrine system and hypothalamic-pituitary-gonadal axis.
Sexual precocity is a common childhood endocrine disease.The pathogenesis of sexual
precocity has not been fully elucidated. RFRP3/GPRl47 signal pathway is able to inhibit
the reproductive capability in avians and mammals, probably by acting on the GnRH
neuron and pituitary to regulate gonadotrophin synthesis and release. However, little is
known about the role of RFRP3 in puberty development and sexual precocity.

Objective:
To observe the dynamic changes of RFamide related peptide 3/G proteincoupled
receptor 147 (RFRP3/GPR147) in hypothalamic during puberty development
and explore their role in precocious puberty based on a female rat model.

Methods:
The Sprague-Dawley female rats were randomly divided into three groups,
normal, vehicle, and precocious puberty model. At 5 days old, the rat model with
precocious puberty was prepared by subcutaneously injecting a mixture of danazoldissolved
ethanol and glycol. At different day-age (15, 25, 30, 35, and 40 days), the
levels of estradiol(E2), follicle-stimulating hormone(FSH), and luteinizing hormone (LH)
in the peripheral blood were detected by the enzyme-linked immunosorbent assay, the
messenger ribonucleic acid (mRNA) expressions of RFRP3, gonadotropin releasing
hormone and GPR147 were examined by real-time polymerase chain reaction(R-T
PCR). RFRP3 positive cells were observed using Immunofluorescence confocal
microscopy.

Results:
At 25 and 30 days, the levels of sex hormones and the uterus coefficients were
significantly higher in the precocious puberty model group than those in the normal and
vehicle groups. The ovarian morphological development in the precocious puberty
model rats was significantly earlier than those in the normal and vehicle groups. The
mRNA expressions of RFRP3/GPR147 and GnRH in the precocious puberty model
group gradually increased and peaked at 25 days. The different day-age and the
interaction have significant statistical significance on the expression of RFRP3 mRNA,
while the levels of RFRP3 mRNA in the model group and vehicle groups have no
significant statistical significance. There was statistical significance between the model
group and vehicle groups in different day-age on the expression of GPR147 mRNA.The
expression of hypothalamic RFRP3/GPR147 mRNA and RFRP3 positive cells gradually
decreased with puberty onset. At 35 days, the levels of RFRP3 mRNA and GPR147
mRNA were significantly lower in the precocious puberty model group than those in the
vehicle groups. Meanwhile, the levels of LH in the precocious puberty model rats
reached its peak at this age. In the vehicle group, the levels of RFRP3 mRNA and serum
LH were gradually increased and LH nearly peaked at 35 day-age. Subsequently, it
gradually decreased and reached the lowest level at 35 day-age. The expression of
RFRP3 mRNA and LH were positively correlated.

Conclusion:
The findings suggested that RFRP3/GPR147 signaling pathway may be
involved in the pathogenesis of sexual precocity by regulating puberty development and
sexual maturity in rats.