Fertilization and early embrology: A sequential analysis of the effect of progesterone on specific sperm functions crucial to fertilization in vitro in infertile patients*

Abstract

The objective of these studies was to evaluate the modulatory effect(s) of progesterone on sperm functions crucial to fertilization in infertile men with abnormal sperm parameters. A prospective, controlled study applying a sequential diagnostic analysis capable of identifying specific dysfunctions of the male gamete was performed. Patients (n = 14) were allocated to the study group if they had a history of infertility of > 1 year duration and after semen evaluation showed teratozoospermia (< 14% normal sperm forms as diagnosed by strict criteria) or terato-asthenozoospermia (< 50% progressive motility). After swim-up separation of the motile sperm fraction, the following functions were assessed with and without previous exposure to progesterone (1.0 micrograms/ml): acrosome reaction (using Pisum sativum agglutinin), hyperactivated motility (using a computerized semen analyser), sperm-zona pellucida binding (in the hemizona assay), sperm-zona pellucida penetration (in a sperm-zona penetration assay), and sperm-oocyte penetration (using the hamster zona-free oocyte/sperm penetration assay). Progesterone did not affect the percentage of acrosome-reacted spermatozoa after 1 or 3 h of incubation. Hyperactivated motility was significantly enhanced by progesterone after 1 h (12 +/- 4 versus 6 +/- 2% in controls; P < 0.02). Although progesterone did not affect sperm-zona binding, it significantly enhanced both sperm-zona pellucida penetration (27 versus 12% in controls; P = 0.03) and sperm-oocyte penetration (15 versus 8% in controls; P < 0.05). Because those sperm functions enhanced by progesterone are crucial to fertilization, the steroid may have value in the treatment of some male-factor patients undergoing assisted reproductive therapy.

Human Sperm Chemotaxis: Is Progesterone a Chemoattractant?1

“…1; [11])? Progesterone is well known to cause sperm hyperactivation [24][25][26][27]. We found that during approach to a progesterone-containing well, about half of the spermatozoa present in the accumulation area acquired hyperactivation-like motility.…”

Modelling human sperm-egg interactions in vitro: signal transduction pathways regulating the acrosome reaction

“…As human oviductal fluid is considered to be the best mimic of the physiological conditions spermatozoa encounter in vivo , the latter observations support the concept that progesterone does not induce the acrosome reaction in vivo. Rather, progesterone binding is postulated to enhance the ability of human spermatozoa to undergo a zona pellucida-induced acrosome reaction (Sueldo, 1993;Oehninger et al, 1994;Benoff et al, 1995b;Jacob et al, 1998); that progesterone exposure creates a different and increasing intracellular ionized calcium baseline (Brucker et al, 1994) is consistent with this hypothesis.…”

Kinetics of the Progesterone-Induced Acrosome Reaction and Its Relation to Intracellular Calcium Responses in Individual Human Spermatozoa1

“…The steroid hormone progesterone (P), which is secreted at micromolar levels by the oocyte and steroidogenic cumulus cells that surround it [6,7], can also initiate AR in vitro [8][9][10][11][12][13][14]. Due to the difficulty in obtaining human ZP, P is the only wellcharacterized physiological agonist of AR in human sperm.…”