Electrolyte composition of rete testis fluid and cauda epididymal plasma and spermatozoa from rats following gossypol treatment

Characterization of ion interference in gossypol consumption

The goal of the present investigation was to show that gossypol has the potential of ion interference capable of affecting the metabolic activation of the biologic system. Gossypol was administered orally at 20 mg/kg body weight (bw) for 8 weeks and the animals were fed a controlled diet. At the end of the experiment, liver supernatant was subjected to atomic absorption spectrometry. The characteristic ion interferences were examined for calcium, ferrous, sodium, magnesium, potassium and chloride ions. Glutathione level and lactate dehydrogenase activity were also monitored. The peak heights for calcium and ferrous ions were high and low respectively but the ion ratio for calcium is suggestive of a ligand-like substance that may be cumulative, thereby leading to biologic magnification (toxicity).

Pharmacokinetic and pharmacodynamic studies of the effect of ketoconazole on reproductive function in male rats

A single oral dose (300 mg kg-1) of ketoconazole induced reversible immobilization of rat epididymal spermatozoa at 8-24 h after dosing. This occurred when the drug concentrations in cauda epididymal fluid and seminal plasma were at their peak (18.0 +/- 7.3 and 13.5 +/- 3.0 micrograms ml-1, respectively), and which was preceded by a peak plasma concentration (Cmax) of 64.82 +/- 2.47 micrograms ml-1 at 5.15 +/- 0.68 h (Tmax). In contrast, rete testis fluid collected from the same animals contained only minute amounts of ketoconazole (0.47 +/- 0.34 micrograms ml-1). Plasma testosterone concentration showed a sharp decline within 4 h of dosing, followed by a recovery from suppression, even after administration of a low dose (100 mg kg-1) which did not affect sperm motility. These findings suggest that ketoconazole gains access to the post-testicular sex organs and affects the mature spermatozoa therein much more readily than it affects testicular spermatogenesis. Synthesis and screening of compounds with a related molecular structure but which exhibit more pronounced spermicidal and less pronounced anti-androgenic effects are thus suggested in the hope that rapidly acting and reversible male contraceptives might be identified and developed.

Penetration of ethanol into the male reproductive tract

We studied the pharmacokinetics of ethanol in the rat rete testis fluid, interstitial fluid, seminiferous tubules, epididymal fluid, and whole testis after 0.75 g/kg and 1.5 g/kg intraperitoneal injections. Ethanol concentration in these tissues was compared to that in capillary and arterial blood. The data was characterized by fitting to a mathematical model. The highest ethanol concentrations in orbital capillary blood were measured 10 min after the injections. Ethanol content in testis homogenate and interstitial fluid did not generally differ from that of orbital blood. However, in rete testis fluid the highest ethanol values were measured at 60 min by the 1.5 g/kg dose and at 30 min by 0.75 g/kg. Ethanol values before this differed from those of capillary blood and interstitial fluid (p less than 0.05-0.001). In seminiferous tubules, the highest ethanol concentration was reached at 20 min, and ethanol content was in general lower than in orbital blood (p less than 0.001-0.01). Ethanol levels in epididymal fluid were comparable to capillary blood. The transportability factor from the model for rete testis was low, which indicates a barrier of penetration of ethanol from blood. In addition, water contents of testicular compartments were calculated. The area under the curve values of rete testis and seminiferous tubules were approximately 10 and 30%, respectively, smaller than that of interstitial fluid, for example. Therefore, the germ cells are somewhat better protected from ethanol than the interstitial cells.

Effect of gossypol on the concentration of sodium and potassium in the rat epididymis

The effects of administration of gossypol acetic acid (7.5 mg/kg daily for 4 weeks) on the concentration of Na+ and K+ in the rat epididymis was assessed. Epididymal fluid samples, collected by micropuncture, from the caput, corpus, proximal cauda and distal cauda epididymis from gossypol-treated and control animals were analysed for Na+ and K+ concentrations. Gossypol-treated males failed to impregnate healthy females, presumably because their sperm were immotile. In gossypol-treated rats, Na+ levels decreased significantly (P less than 0.01) in the caput, corpus, proximal and distal cauda epididymis. In contrast, the K+ concentration was increased significantly (P less than 0.05) only in the caput and corpus epididymis. This altered electrolyte milieu may be responsible, to some extent, for immotility and hence infertility.

The correlation between the gossypol contents in blood plasma, rete testis fluid, and cauda epididymal fluid following chronic treatment with gossypol in rats

Concentrations of gossypol in blood plasma, rete testis fluid, and fluid from the caudia epididymidis were measured simultaneously by high performance liquid chromatography in rats treated with gossypol (15 mg/kg daily for 3 weeks). Antispermatogenic effects were demonstrated by loss of sperm motility in the cauda epididymidis and structural changes in the testis. It was found in these treated rats that concentrations of gossypol were lower in rete testis fluid compared with blood plasma but increased significantly in fluid from the cauda epididymidis. The results indicate a restriction of the blood-testis barrier to gossypol and its local concentration in the epididymis after fluid resorption.