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J F Rodriguez-Sierra

Publications and source records attributed to J F Rodriguez-Sierra.

61 records · Page 4Linked to original sources
PubMed1977

Role of catechol estrogens in activation of lordosis in female rats and guinea pigs.

In a variety of experiments, we tested the effectiveness of the 2-hydroxylated estrogen in facilitating sexual receptivity. A single injection of 2-hydroxy-estradiol-17beta (2-OHE2) to ovariectomized rats or 2-hydroxy-estrone (2-OHE1) to ovariectomized guinea pigs was ineffective in priming animals for facilitation of sexual receptivity even when a subsequent injection of progesterone was administered. The only facilitatory effect of catechol estrogens on lordosis that was demonstrated in this study occurred when 2-OHE2 was injected in combination with E2 and a subsequent injection of progesterone was given to rats. These results suggest a cooperatively between catechol estrogen and E2, but they also indicate that catechol estrogens, by themselves, do not play a crucial role in mediating sexual receptivity in rodents.

Animals↗
PubMed1976

Monoaminergic mediation of masculine and feminine copulatory behavior in female rats.

Ovariectomized rats treated with testosterone propionate (TP; 100 mug/kg X 6 days) and para-chlorophenylalanine (pCPA; 100 mg/kg X 3 days), a serotonin synthesis inhibitor, showed more masculine copulatory behavior (including the ejaculatory pattern) than did females receiving either TP or pCPA alone. The facilitatory effect of pCPA on the masculine copulatory behavior in females was not potentiated by pargyline (50 or 100 mg/kg), a monoamine oxidase inhibitor; instead, pargyline antagonized the effect of pCPA. Apomorphine (100 mug/kg), a dopamine receptor stimulant, did not increase masculine copulatory behavior in TP treated females. Adopaminergic facilitatory effect was therefore not demonstrated. These results suggest a serotonin-mediated inhibition of masculine copulatory behavior in female rats. When feminine copulatory behavior was tested, females receiving TP plus pCPA plus pargyline, TP plus pargyline, or TP plus apomorphine displayed lordosis in response to mounting by male rats. Lordosis did not occur after administration of TP, PCPA, or pargyline, individually or in any other combination. The responses in pargyline groups are consistent with the hypothesis of a noradrenergic facilitatory system for lordotic behavior. The responses in the apomorphine group are discussed in terms of a possible role for low level dopaminergic stimulation in facilitating lordosis.

Adrenal Glands↗
PubMed1976

Hypophysectomy facilitates sexual behavior in female rats.

Lordosis was elecited in 49% of 87 hormonally untreated, hypophysectomized-ovariectomized (hypox-ovx) female rats in response to palpation of the flanks and perineum (vaginal stimulation was not applied). By contrast, only 12% of 113 hormonally untreated ovariectomized (ovx) rats showed lordosis in response to such stimulation. Subsequently, hypox-ovx and ovx-only rats were given daily injections of 1 mug/kg estradiol benzoate (EB) and tested for sexual receptivity with males. Teh estrogen-treated hypox-ovx females became sexually receptive significantly earlier, and exhibited higher lordosis quotients and more soliciting behavior, than the estrogen-treated ovx-only rats. The increased sexual responsiveness in the hypox-ovx rats could be due to increased LRH activity. To test this, we treated hypox-ovx rats with dihydrotestosterone propionate (DHT-P), which suppresses plasma LH levels but is relatively ineffective in inducing sexual receptivity, and found a significant depression of lordosis responsiveness. These experiments suggest that hypox-ovx females show a heightened responsiveness to hormonal and/or sensory factors that induce a lordosis response, possibly because of increased LRH activity.

Animals↗
PubMed1975

Vaginal stimulation in rats induces prolonged lordosis responsiveness and sexual receptivity.

Sexual receptivity to males resulted from stimulation of the vagina with a glass rod in previously unreceptive ovariectomized, estrogen-treated rats. Several minutes of rejection behavior preceded the receptivity. In a second study, manual palpation was used to determine the duration of the lordosis response facilitation. Initially, all females were unresponsive to manual flank-perineum stimulation (palpation). Vaginal stimulation plus palpation, which together elicit lordosis, facilitated subsequent lordosis responses to palpation. This effect persisted for several hours after the vaginal stimulation was applied. Vaginal stimulation alone, which was ineffective in eliciting lordosis, also facilitated lordosis in response to subsequent palpation. Repeated palpation did not facilitate lordosis. These prolonged effects were independent of hormone treatment.

Animals↗
PubMedDate not supplied

Effects of neuropeptide Y on LH, FSH and TSH release in male rats.

These experiments were undertaken to investigate the effects of systemically administered neuropeptide Y (NPY) on gonadotropin secretion in the intact male rat and to determine whether the effects observed might be mediated by a direct action of NPY alone on the anterior pituitary gland (APG). Subcutaneous administration of 10 micrograms of NPY caused a greater than 2-fold increase in serum luteinizing hormone (LH) concentration at 15 min after injection but was without effect on serum follicle-stimulating hormone (FSH) or thyrotropin-stimulating hormone (TSH) levels. The addition of NPY (final concentrations of 10(-8) to 10(-11) M) or the structurally similar neuropeptide, rat pancreatic polypeptide, to culture medium containing hemi-APG did not alter the release of LH, FSH, or TSH. The results indicate that systemically administered NPY can elevate serum LH concentration in intact male rats. This effect does not appear to be due to NPY acting alone at the level of the APG.

Animals↗
PubMedDate not supplied

Lesions of the preoptic area facilitate lordosis behavior in male and female guinea pigs.

Male and female guinea pigs received radiofrequency lesions in the medial preoptic area (MPOA). Animals were gonadectomized, treated with estrogen and progesterone, and tested for the occurrence of the lordosis response to manual stimulation. Females with MPOA lesions exhibited enhanced lordosis behavior, shorter latencies to heat, longer duration of heat and longer maximum lordosis duration than sham control females. In males with MPOA lesions, the lordosis response could be elicited by manual stimulation, in contrast to no response in the sham control males. Furthermore, MPOA-lesioned males were insensitive to the inhibitory effects of progesterone on lordosis behavior, while MPOA-lesioned females were as sensitive as sham controls to the inhibitory effects of progesterone. The results suggest that a neural mechanism resides within the MPOA which inhibits the occurrence of lordosis behavior in both male and female guinea pigs and which is not involved in a sexual dimorphism in responsiveness to progesterone.

Animals↗