TITLE:
Periconceptional growth hormone treatment alters early uterine environment
AUTHORS:
Jill M. Koch, Caleb O. Lemley, Ronald R. Magness, Matthew E. Wilson
KEYWORDS:
Growth Hormone; Uterine Environment; Embryo
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.3 No.2,
April
18,
2013
ABSTRACT: We
have shown that an injection of sustained release growth hormone (GH), given
just prior to breeding, results in lambs that are 25% heavier at birth, with an
altered body composition as evidenced by an increased abdominal girth, but no
difference in crown rump length. The mechanisms by which these differences
occur from a single periconceptional injection are not yet known. Therefore,
the objective of this experiment was to determine the effect of an injection
of GH given prior to breeding on the composition of the uterine luminal
environment and the embryo at the time of blastocyst. Ewes were synchronized
with two injections of prostaglandin F2α given eight days apart. On the day of the second injection, ewes
were randomly assigned to be given an injection of sustained release GH or
remain as controls and penned with a ram. On day 6.5 following breeding embryos
were collected. Prior to surgery a jugular blood sample was taken to determine
plasma progesterone and urea concentration. The uterine content of urea,
prostaglandin F2α,
prostaglandin E2, transforming growth factor β-1 (TGF β),
and nitric oxide metabolites were measured. Collected embryos were differentially
stained to calculate a trophectoderm to inner cell mass ratio. The
concentration of progesterone in maternal plasma was greater in the treated
group compare to controls, but blood urea nitrogen was not different between
groups. The uterine content of urea in the GH group was lower than that of the
control group. There was a trend for TGF β to be increased in the GH treated group compared to control (P = 0.07). There
was no difference (P > 0.05) in the total uterine content prostaglandin F2α, prostaglandin E2 or nitric
oxide metabolites. The trophectoderm to inner cell mass ratio was not different
between treatment groups. Thus, we suggest that the observed difference in
fetal development following periconceptional growth hormone administration just
prior to breeding may be the result of an alteration in the uterine luminal
environment, which may alter the cellular program of the conceptus and later
development beyond the embryonic stage.