Effects of 17beta-aminoestrogens on the sexual behavior of female rats.

17beta-aminoestrogens (AEs) produce anticoagulant effects in rats contrastingwith 17beta-estradiol (E2) procoagulant effects, their estrogenic effects are similar to E2, decreasing serum luteinizing hormone (LH), increasing uterine weight (Uw), activate transcription through the ERalpha and ERbeta receptors and pentolame induces progesterone (P) receptors in the anterior pituitary of ovariectomized (Ovx) rats similarly to E2, suggesting possible effects on female rats' sexual behavior. This work evaluated the AEs prolame, butolame, pentolame compared to E2 and estradiol benzoate (EB) as facilitators on the rat lordotic behavior. Dose-response curves were performed in rats by single subcutaneous (s.c.) injection (timezero) of: E2 (approximately 0.3, 3, 30, 60, 300 microg/kg); EB (approximately 0.4, 4, 40, 80, 400 microg/kg); prolame, butolame, pentolame (approximately 40, 400, 2000 or 4000 mg/kg), vehicle (corn oil; 300 microL/day; approximately 1.2 mL/kg) as control; 24 h after, P (1 mg/rat in 100 microL of corn oil; approximately 4 to 5 mg/kg) was administered, and 5 to 7 h later LQ was evaluated (number of lordosis displays/number of mounts x 100). E2, EB and AEs followed by P administration, induced lordosis in a dose-dependent manner. Prolame induced an LQEmax of 92, butolame85, EB 81, pentolame 44 and E2 43. The most potent was EB (LQED50 of 4.1 +/- 0.5 microg/kg); then E2 10 microg +/- 2.2/kg; prolame 268 +/- 19 microg/kg; butolame 402 +/- 21 microg/kg, and pentolame 1037 +/- 28 microg/kg. The AEs LQ potency decreases as length substitution on the amine group in C-17 increases. AEs LQDE50 values correlate with previous Uw DE50, LH ID50 and binding studies indicates mediation of the response by estrogen receptors. AEs facilitate sexual behavior of Ovx rats as partial estrogenic agonists.

Sperm-attracting activity in follicular fluid associated to an 8.6-kDa protein.

Follicular fluid is made of both follicular cell-secreted molecules as well as blood infiltration into the follicle. Sperm-attracting activity has been associated to column-filtered proteins as well as to progesterone. Here we report the initial characterization of a protein with this activity. Follicular fluid was collected from preovulatory follicles in freshly obtained ovaries from a local slaughterhouse. Fluid was cleared from cells and fractionated by size exclusion chromatography and polyacrylamide gel electrophoresis. For gamete interaction, sperm were allowed to swim in an agarose-covered slide designed to separate two wells by a rod in a fixed pattern. At each well, a semisolid agarose solution containing either the attractant with oocytes or control solution in one end, whereas capacitated boar sperm was at the opposite well. Sperm bound to oocytes were evaluated under phase contrast microscopy. Results show that fluid from preovulatory follicles have a sperm attracting activity and that this activity can be associated with an 8600 Dalton protein that at the N-terminal end exhibit close relation to Apoliprotein B2.

Ca2+/calmodulin system: participation in the progesterone-induced facilitation of lordosis behavior in the ovariectomized estrogen-primed rat.

We studied the effect some drugs that participate in the Ca2+/ calmodulin system have on the progesterone (P) facilitation of lordosis behavior in ovariectomized estradiol (E2) primed rats. We injected rats 44 h after E2 priming with 2 mg P together with various dosages of one of the following compounds: pentobarbital, trifluoperazine (TPZ), promethazine (PMZ), Chlorpromazine (CPZ), haloperidol (HAL), pimozide (PIM), and verapamil (VER). Then 4 h after treatment, animals were tested for sexual behavior, expressed as the lordosis quotient (LQ). All drugs at 4 mg/kg or higher inhibited lordosis, but only HAL, PIM, and VER were active at 1 mg/kg. The maximum level of activity was shown by PIM, although at the dose of 8 mg/kg no statistical differences were found between this compound and TPZ or HAL. Pentobarbital (25 mg/kg) showed no significant difference from saline-treated controls. The activity of the tested drugs on the facilitation of sexual behavior appears to be related to their efficiency as inhibitors of calmodulin (CaM)-dependent phosphodiesterase and as ligands for the Ca(2+)-CaM complex.

Ca2+/calmodulin system: participation on rat sexual hypothalamic differentiation.

Modifications of male rat hypothalamic sexual differentiation after neonatal administration of drugs that participate on the Ca2+/calmodulin system (haloperidol, trifluoperazine, penfluridol, pimozide, and verapamil) were studied. Pups treated 72 h after birth were behaviorally tested on day 120 of extrauterine life. Five tests for homotypical behavior were conducted. Afterwards animals were castrated and tested twice for heterotypical (female) behavior under replacement hormonal therapy. Fifty percent (80% in the case of pimozide) of all treated males showed lordotic behavior compared with none of the controls. Haloperidol (39%, lordosis quotient) and pimozide (40%, lordosis quotient) were more active than the others. Results obtained with verapamil were not statistically different from the controls. Pimozide was the most active agent influencing the appetitive masculine behavior (mount latency, intromission latency, and postejaculatory interval). Verapamil was more efficient than the rest of the drugs on the consummatory behavior (mount latency, intromission frequency, interintromission interval, and ejaculatory latency). Our results support the participation of the Ca2+/calmodulin system in hypothalamic sexual differentiation and in the differential modulation of the masculine and feminine behavioral patterns.

REM sleep deprivation facilitates the estrogen effect on heterotypical sexual behavior in male rats.

Gonadectomized male rats were submitted to REM sleep deprivation (REMd) for 120 hr and their hetero and homotypical sexual response to estradiol benzoate (EB) was tested. Subjects (Ss) receiving 20 micrograms EB showed lordosis quotients (LQ) twice as high as those receiving 10 micrograms EB and at the same time the LQs in these groups were higher than in the non-REMd groups. Gonadectomized-adrenalectomized control Ss showed the highest levels of lordosis throughout the experiment. REMd by itself does not produce lordosis response. The results indicate that the brain structures underlying this behavior in males are probably similar to those in females, since REMd increases lordosis in both cases. The lack of homotypical sexual behavior normally observed in gonadectomized male rats does not seem to be affected by this treatment. The issue of adequate controls for REMd experiments is discussed.

Effects of REM deprivation on the lordosis response induced by gonadal steroids in ovariectomized rats.

Ovariectomized rats were submitted to REM sleep deprivation (REMd) using the water tank technique and their behavioral responsiveness (lordosis) to gonadal steroids was tested. In Experiment 1, animals received 2 micrograms of estradiol benzoate (EB) followed by 2 mg of progesterone (P) 44 hours later. Several REMd periods (12, 72, 96 and 120 hr) were applied, all ending four hr after P. REMd animals showed significantly lower lordosis quotients (LQ) than undisturbed sleep animals regardless of the duration of the deprivation period. In Experiment 2, animals received a single dose of EB (2 micrograms) and were REMd for 120 hours. Animals were tested daily to evaluate their LQ. EB, at this dose level, failed to elicit significant lordosis behavior in undisturbed sleep rats. REMd rats gradually increased their LQ values reaching maximal levels at 72 hours. Adrenalectomized control groups receiving the same hormonal treatment responded similarly to the experimental groups, thus discarding the participation of adrenal steroids in these effects. The present results show that REMd differentially affects the response to E and P in ovariectomized rats, enhancing the former and inhibiting the latter.

Depressant effect of androgens on the cat brain electrical activity and its antagonism by ruthenium red.

Electroencephalographic synchronization and a fall in the multiunit activity was observed in the mesencephalic reticular formation, ventromedial hypothalamus and dorsal hippocampus following intravenous administration of some 5 alpha and 5 beta-reduced testosterone derivatives. The most potent compounds were androsterone and androstanediol which have the 3 alpha-hydroxy-5 alpha ring A configuration. Steroids with 5 beta reduction, i.e. 5 beta-dihydrotestosterone, etiocholanolone and epi-etiocholanolone, at high doses produced the inhibitory effect. Testosterone and its closer 5 alpha metabolites (5 alpha-dihydrotestosterone and 5 alpha-androstanedione) were ineffective. The depressive effect of androsterone on neurones was antagonized by the intraventricular injection of ruthenium red. On the other hand, the convulsant effect of ruthenium red was prevented or diminished by the action of androsterone. These findings support the hypothesis that testosterone metabolites reduced either at 5 alpha or 5 beta position can act in the brain at a membrane level and raise the possibility that testosterone may be a prehormone in the regulation of excitability in some brain functions.