Reversible Inhibition of Spermatogenesis in Rats Using a New Male Contraceptive, 1-(2,4-Dichlorobenzyl)-Indazole-3-Carbohydrazide1

Abstract

The oral male contraceptive agent 1-(2,4-dichlorobenzyl)-indazole-3-carbohydrazide (AF2364) is a new analogue of indazole-carboxylic acid. AF2364 was orally administered to rats at 50 mg/kg body weight once weekly for five consecutive weeks. The effects on fertility efficacy, hormonal profile, organ weights, tissue morphology, and serum microchemistry were examined. Complete infertility was noted in rats 29 days after the initial dose of AF2364 and continued until 90 days. Fertility resumed in 25% of the group after 104 days and had resumed in 75% of the rats by the last mating at 197 days. Morphological examination of the testis showed rapid exfoliation of elongated spermatids and the generation of large multinucleated cells 6 days after the first treatment, with depletion of most germ cells after 40 days. Normal spermatogenesis was noted in 95% of the tubules in the animals that were fertile at 210 days. Morphological analysis of the epididymal compartments revealed reduced lumen size, whereas the prostate exhibited an increase in the glandular lumen with a reduction in epithelium height. No morphological changes were detected in the kidney, liver, and cerebrum by light microscopy. Kidney and liver function, as evaluated by serum chemistry, were not affected by the drug treatment. AF2364 did not alter the levels of FSH, and only minimal changes were noted for LH and testosterone, suggesting that the hypothalamic-pituitary-testicular axis was not affected. These results illustrate the potential of AF2364 as a male contraceptive.

Anchoring Junctions As Drug Targets: Role in Contraceptive Development

“…7), was identified and selected from more than a dozen newly synthesized analogs of lonidamine. Similar to lonidamine, adjudin was shown to perturb adhesion between Sertoli and germ cells Grima et al, 2001). Note that cell adhesion was not compromised in other organs when this drug was administered orally, or by intraperitoneal or intramuscular injection, perhaps because these organs lack the apical ectoplasmic specialization and induced a significant surge in the steady-state level of testin at the apical ectoplasmic specialization (Table 1) .…”

“…After detailed morphological analyses, adjudin was ultimately shown to perturb adhesion between Sertoli and most, but not all, germ cells. Adhesion between Sertoli cells and spermatogonia and between Sertoli cells and some primary spermatocytes, however, was largely unaffected Grima et al, 2001; (Fig. 9).…”

“…It is noteworthy that several potential nonhormonal contraceptives, such as CDB-4022 and adjudin (formerly called AF-2364), have been shown to exert their effects, at least in part, on Sertoli-germ cell anchoring junctions, leading to depletion of germ cells from the seminiferous epithelium and reversible infertility Grima et al, 2001;Hild et al, 2007Hild et al, , 2001). This approach of male contraception is associated with minimal side effects, because its effects are exerted at the site of Sertoligerm cell contact.…”

“…This approach of male contraception is associated with minimal side effects, because its effects are exerted at the site of Sertoligerm cell contact. Equally important, if adhesion between Sertoli cells and spermatogonia remains largely unaffected after treatment, fertility is regained, as is the case with adjudin Grima et al, 2001). Thus, it is critical that we understand the molecular architecture and the regulatory mechanisms underlying Sertoligerm cell adhesion, given its importance in spermatogenesis and in the development of nonhormonal male contraceptives.…”

Blood–testis barrier dynamics are regulated by an engagement/disengagement mechanism between tight and adherens junctions via peripheral adaptors

“…Adult rats (n ϭ 4 rats per time point; Ϸ300 g of body weight) were fed with a single dose of Adjudin at 50 mg͞kg of body weight (17,18). Control rats received vehicle only [0.5% (wt͞vol) methylcellulose in water].…”