Biology Reference
In-Depth Information
SC administration of human kisspeptin-54, at a higher dose of 100 nmol/kg, to
10-week-old adult male Wistar rats also led to a rise in LH from a barely detect-
able baseline to ~32 ng/mL at 2 h, before falling to 10 ng/mL at the end of the 4 h
sampling period. In these males, FSH rose threefold from a baseline of 10 ng/mL
and was yet to plateaux at the end of the 4 h sampling period [ 1 ]. The effect of a
single 50 nmol bolus of SC kisspeptin-54 was compared with an equimolar dose
of GnRH in rats. Kisspeptin-54 increased plasma LH ~5-fold at 60 min, FSH
~2-fold, and testosterone ~2.5-fold at 60 min. Kisspeptin-54 and GnRH were
essentially equally effective in stimulating gonadotropin release at this dose [ 2 ].
Acute Central Administration of Kisspeptin
Gottsch et al. were the fi rst authors to study the in vivo effects of exogenous kiss-
peptin [ 3 ]. Central administration of a 1 fmol dose of kisspeptin-54 to adult male
C57BL/6 mice stimulated LH secretion threefold at 30 min when compared with
vehicle [ 3 ]. Although doses of up to 1.2 nmol were examined, maximal LH secretion
at 30 min post-administration (~7-fold) was found following a 10 fmol dose [ 3 ].
ICV administration of kisspeptin-10 in adult male Wistar rats dose-dependently
increased plasma LH levels at 1 h (saline: 0.3 ng/mL; 1 nmol kisspeptin-10: 5 ng/mL;
3 nmol kisspeptin-10: 9.4 ng/mL) [ 4 ]. Plasma FSH was only signifi cantly increased
at this time following the 1 nmol dose [ 4 ]. After a 3 nmol dose of ICV kisspeptin-10
treatment, LH was signifi cantly increased at just 10 min post-injection (saline:
1.0 ng/mL; kisspeptin: 1.7 ng/mL), and continued to rise, peaking at 60 min post-
injection (saline: 0.3 ng/mL; kisspeptin: 5.2 ng/mL). Enhancement of FSH secretion
was slower, being only signifi cantly increased at 60 min post-injection (saline:
16.9 ng/mL; kisspeptin: 34.4 ng/mL) [ 4 ]. In another study, ICV administration of
murine kisspeptin-10 (at doses of 10-1,000 pmol) in pubertal (45 day old) male
Wistar rats elicited LH rises of 7-8-fold at 15 min post-injection, and dose-dependent
rises at 60 min post-injection, when compared with controls (Table 4.1 ) [ 5 ].
ICV murine kisspeptin-10 in pre-pubertal gilts (130 day old female pigs) at doses
of 10
g (75 nmol) increased LH levels from 0.25 ng/mL to
peak levels of 2 ng/mL and 3.5 ng/mL, respectively. FSH was also increased ~2-fold
at both doses [ 6 ]. Hence, ICV kisspeptin was effective from a dose of 10 pmol in the
rat and 7.5 nmol in the gilt, raising LH levels from as early as 10 min post-
administration and achieving highest levels by 60 min post-injection.
µ
g (7.5 nmol) or 100
µ
Acute Intravenous Administration
Kisspeptin-10 has a short in vivo plasma half-life of only 4 min in humans [ 7 ]; there-
fore, an intravenous bolus (IV bolus) of kisspeptin-10 would be expected to have a
short duration of effects. An IV bolus of murine kisspeptin-10, via intracardiac
Search WWH ::




Custom Search