Pf. Blackmore, RAPID NON-GENOMIC ACTIONS OF PROGESTERONE STIMULATE CA2+ INFLUX AND THE ACROSOME REACTION IN HUMAN SPERM, Cellular signalling, 5(5), 1993, pp. 531-538
This review summarizes some recent findings in human sperm which show
that progesterone and 17alpha hydroxyprogesterone are able rapidly (wi
thin seconds) to elevate [Ca2+]i and elicit the acrosome reaction (AR)
via a non-genomic cell surface receptor. Progesterone promotes a tran
sient elevation in [Ca2+]i which is blocked by extracellular La3+ and
Ni2+ and removal of extracellular Ca2+ following chelation with EGTA.
Some studies suggest that polyamines, trypsin-like proteases, and prog
esterone receptor aggregation are involved in progesterone-induced Ca2
+ influx and AR. The receptor is not stimulated by the potent syntheti
c progestigins (e.g. promegestone, norethynodrel, megestrol acetate, c
yproterone acetate) and is weakly antagonized by the genomic anti-prog
estins RU 486 and ZK 98.299. The sedative-hypnotic 3alpha hydroxyl A-r
ing reduced pregnane steroids, which are powerful activators of the GA
BA(A) Cl- channel, are weak activators of Ca2+ influx and the AR. Thes
e data suggest that human sperm have a cell surface steroid receptor w
hich is unlike the genomic progesterone receptor and the GABA(A) Cl- c
hannel steroid receptor.