Effect of norethisterone and its A-ring reduced metabolites on the acrosome reaction in porcine spermatozoa

Martinez, Guillaume; Zayas, Héctor; Ducolomb, Yvonne; Garcı́a, Gustavo; Betancourt, Miguel; Castro, Ivone

doi:10.1111/j.1439-0272.2002.tb02944.x

Cited by 4 publications

(2 citation statements)

References 28 publications

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“…An effect of progesterone on acrosome reaction has also been shown in spermatozoa from other species such as mouse (Murase and Roldan, 1996), hamster (Llanos et al, 1993), stallion (Meyers et al, 1993), guinea pig (Zhang et al, 2000), goat (Somanath and Gandhi, 2002), boar (Barboni et al, 1995), dog (Sirivaidyapong et al, 2001), and pig (Martinez et al, 2002).…”

Section: Introductionmentioning

confidence: 85%

In vitro effect of gamma‐aminobutyric acid on bovine spermatozoa capacitation

Ritta

Bas

Tartaglione

2004

Molecular Reproduction Devel

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Sperm capacitation is defined as the maturational changes that render a sperm competent for fertilization and occurs in the female reproductive tract. Identification of the factor/s that regulate sperm capacitation would allow the understanding of these phenomena. Among these factors, gamma-aminobutyric acid (GABA) has recently become as a putative modulator of sperm function. The aim of this study was to explore the presence of a GABAergic regulation of bovine sperm capacitation as well as the possible intracellular mechanisms involved. GABA was detected in fresh semen by a sensitive radioreceptor assay (spermatozoa, 0.064 +/- 0.003 nmoles/10(6) cells; seminal plasma, 23.21 +/- 1.16 nmoles/ml). Scatchard analysis of [(3)H]-muscimol binding to sperm membranes yielded a linear plot consistent with a single population of binding sites (K(d) = 3.87 nM, B(max) = 417 fmol/mg prot.). [(3)H]-muscimol specific binding to sperm membranes was significantly inhibited by the GABA A receptor (GABA A-R) antagonist bicuculline and by the agonists muscimol and isoguvacine. Addition of GABA to the incubation medium resulted in a concentration-dependent increase in the percentage of capacitated spermatozoa (chlortetracycline assay). We observed a significant increment on intracellular calcium and cyclic 3',5' adenosine monophosphate (cAMP) concentrations induced by GABA, being the cation influx abolished when the cell suspensions were coincubated with the antagonists bicuculline or picrotoxin. It is concluded that GABA induces sperm capacitation through an intracellular mechanism dependent on calcium influx and cAMP accumulation mediated by a specific GABA A-R.

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Section: Introductionmentioning

confidence: 85%

In vitro effect of gamma‐aminobutyric acid on bovine spermatozoa capacitation

Ritta

Bas

Tartaglione

2004

Molecular Reproduction Devel

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“…The addition of the synthetic progestin levonorgestrel in vitro to capacitated spermatozoa from fertile men is associated with a dose-dependently increased rate of acrosome reaction 58 . Both progesterone and the synthetic progestin norethisterone (NET) increased acrosome reaction in porcine spermatozoa, while the 5a-reduced metabolite of NET, 5a-NET, not only did not induce this reaction, but was able to block the effect of progesterone 59 . Therefore, 5a-NET has to be categorized as a 'non-classical' progesterone antagonist in this respect.…”

Section: Progesterone Actions On Spermmentioning

confidence: 98%

Progesterone: the forgotten hormone in men?

Oettel¹,

Mukhopadhyay²

2004

The Aging Male

176

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'Classical' genomic progesterone receptors appear relatively late in phylogenesis, i.e. it is only in birds and mammals that they are detectable. In the different species, they mediate manifold effects regarding the differentiation of target organ functions, mainly in the reproductive system. Surprisingly, we know little about the physiology, endocrinology, and pharmacology of progesterone and progestins in male gender or men respectively, despite the fact that, as to progesterone secretion and serum progesterone levels, there are no great quantitative differences between men and women (at least outside the luteal phase). In a prospective cohort study of 1026 men with and without cardiovascular disease, we were not able to demonstrate any age-dependent change in serum progesterone concentrations. Progesterone influences spermiogenesis, sperm capacitation/acrosome reaction and testosterone biosynthesis in the Leydig cells. Other progesterone effects in men include those on the central nervous system (CNS) (mainly mediated by 5alpha-reduced progesterone metabolites as so-called neurosteroids), including blocking of gonadotropin secretion, sleep improvement, and effects on tumors in the CNS (meningioma, fibroma), as well as effects on the immune system, cardiovascular system, kidney function, adipose tissue, behavior, and respiratory system. A progestin may stimulate weight gain and appetite in men as well as in women. The detection of progesterone receptor isoforms would have a highly diagnostic value in prostate pathology (benign prostatic hypertrophy and prostate cancer). The modulation of progesterone effects on typical male targets is connected with a great pharmacodynamic variability. The reason for this is that, in men, some important effects of progesterone are mediated non-genomically through different molecular biological modes of action. Therefore, the precise therapeutic manipulation of progesterone actions in the male requires completely new endocrine-pharmacological approaches.

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