Search PubMed⌕ Search

Biomedical subjects

F Naftolin

Publications and source records attributed to F Naftolin.

At least 289 records · Page 16Linked to original sources
PubMed1980

Effects of estradiol-induced lesions of the arcuate nucleus on gonadotropin release in response to preoptic stimulation in the rat.

Female Wistar rats treated with a single subcutaneous injection of 2 mg estradiol valerate (EV) develop gradually progressive, multifocal lesions of the arcuate nucleus. They also exhibit vaginal estrus and endocrine profiles characteristic of animals sustaining anterior hypothalamic deafferentation. In this study, EV-treated females with the arcuate lesions released significantly less LH 1 h following electrochemical stimulation of the medial preoptic area (MPOA) than did normally cycling controls in proestrus. FSH release in response to MPOA stimulation was the same for both groups. As plasma LH concentrations were not significantly different between EV-treated and control animals 1 h after the injection of a potent LHRH analog, the reduced LH response to MPOA stimulation appears to reflect a primarily hypothalamic defect. However, the EV treatment also affected pituitary responsiveness to long-term stimulation as evidenced by reduced LH responses to the LHRH analog after 2 and 3 h. No such differences were seen in the FSH response.

Animals↗
PubMed1980

Ovary-dependent degeneration in the hypothalamic arcuate nucleus.

The effects of estradiol valerate and constant light exposure on the histological appearance of the arcuate nucleus were assessed in female rats. Both of these treatments caused significant increases in the numbers of reactive microglial cells and astrocytic granules in the nucleus. Ovariectomy before either treatment prevented the glial reaction, indicating that the experimental manipulations triggered the secretion of an ovarian product which appears to be selectively toxic to the arcuate nucleus. The fact that monthly injections of estradiol valerate in male rats produced the same profile of degeneration in the arcuate nucleus suggests that the neuropathological agent may itself be estradiol. Ovariectomy also significantly reduced arcuate microglial reactivity associated with normal aging, which suggests that cyclic surges of endogenous estradiol may be capable of gradually producing an arcuate lesion. This phenomenon may accout for the hypothalamic reproductive failure associated with normal aging in the rat.

Animals↗
PubMed1980

Effect of catechol oestrogens on induced ovulation in the immature rat.

The 'positive feedback' effect of exogenous oestradiol-17 beta in advancing ovulation induced by pregnant mare serum gonadotrophin (PMSG) has been used in the present study as a model in which to test the possible oestrogenic or antioestrogenic effects of the catechol oestrogens, 2-hydroxyoestradiol (2-OHE2) and 4-OHE2. Sprague-Dawley rats of 26 days of age were injected with 20 i.u. PMSG together with either vehicle alone or test steroids. The animals were killed 72 h later and the Fallopian tubes were examined for the presence of ova. Advancement of induced ovulation by treatment with oestradiol was confirmed; 2-OHE2, in doses of up to 100 micrograms, influenced neither the time of ovulation nor the number of ova present but 4-OHE2 was equipotent with oestradiol in doses varying from 0.5 micrograms (the minimum effective dose for both steroids) to 10 micrograms. The possible antioestrogenic effect of 2-OHE2 was tested by giving a 100 micrograms dose either at the same time or 2 h before PMSG plus 2 micrograms oestradiol or 4-OHE2. The effects of oestradiol and 4-OHE2 were not altered by this treatment. These data show that, in this model of 'positive feedback', 2-OHE2 has neither an oestrogenic nor an antioestrogenic action but that 4-OHE2 has a potent oestrogenic action, thus raising the question of a physiological role for 4-OHE2 in the regulation of ovulation.

Animals↗
PubMed1980

Response of serum prolactin to catechol estrogen in the immature rat.

The response of serum prolactin to the catechol estrogens, 2-hydroxyestrone (2-OH E1) and 2-hydroxyestradiol (2-OH E2) and their primary estrogens, estrone (E1) and estradiol (E2), was studied in 35-day-old male rats. The subcutaneous administration of 50 microgram of 2-OH E1 or 2-OH E2 significantly suppressed serum prolactin concentrations, but they were not significantly altered by the administration of 50 microgram of E1 or E2.

Animals↗
PubMed1979

Sex-related and cyclic variation of trace elements in rat hypothalamus and pituitary.

The concentrations of 7 trace elements--iron, copper, zinc, arsenic, selenium, bromine, and rubidium--in rat hypothalami and anterior pituitaries were measured by X-ray fluorescence spectrometry. Male, cycling female, and oophorectomized animals were studied under different conditions of reproductive function. Hypothalamic zinc and copper concentrations both rose between proestrus and estrus days and fell again at diestrus. After castration, concentrations of iron, copper, and arsenic were decreased in both pituitary and hypothalamus, while zinc concentrations rose. Male rats had lower pituitary concentrations of iron, copper, zinc, arsenic, and rubidium than cycling females. Under these hormonal manipulations, hypothalamus zinc concentration and gonadotropin secretion appear to be correlated. While injections of copper salts into the hypothalamus can also stimulate gonadotropin release, we did not observe any consistent relation between endogenous hypothalamic copper concentrations and gonadotropins.

Animals↗
PubMed1979

Changing profiles in vasectomy subjects in the past decade.

Two groups of vasectomy patients were reviewed: 376 men operated upon between 1968 and 1971 and 608 between 1974 and 1978. Average age, length of marriage, and number of living children prior to vasectomy were greater in the first group (P less than 0.01). The results are compatible with the idea that couples are planning smaller families and turning increasingly to vasectomy as a reliable permanent birth control method immediately following the completion of their families.

Adult↗
PubMed1979

Gonadotropin, estradiol, and testosterone profiles in homosexual men.

The authors evaluated the gonadotropin-testosterone-estradiol profiles of four homosexual men and four heterosexual men by a multiple-sampling technique. Although there was extensive overlap between the two groups, the homosexual subjects had higher estradiol levels than the heterosexuals (70.3 +/- 19.8 versus 56.8 +/- 10.7 pg/ml) and lower FSH values (5.1 +/- 1.0 versus 13.2 +/- 3.4 mIU/ml). Testosterone and luteinizing hormone levels were comparable in the two groups. These observations suggest that there may be subtle differences in gonadotropin and estradiol secretion in homosexual subjects that can be detected only by repeated sampling.

Adult↗
PubMed1979

Prolonged amenorrhea and oral contraceptives.

Of 106 consecutive women referred for secondary amenorrhea of more than 1 year's duration, 65 were diagnosed as having functional amenorrhea. Of these 65, 29 had amenorrhea directly following discontinuation of oral contraceptives (OC group) and 36 had never used oral contraceptives (NOC group). There was no difference in the incidence of prior menstrual irregularity in either group. Similarly, there was no difference in the resting serum estrone, estradiol, luteinizing hormone, follicle-stimulating hormone, and prolactin levels between the OC and NOC groups. Nor was there a difference between the OC and NOC groups in response to medroxyprogesterone acetate, clomiphene citrate, or luteinizing hormone-releasing factor. Of 106 patients, 17 were proven to have prolactinomas. Eight patients had a prior history of OC use, whereas nine did not. With the exception of elevated serum prolactin levels, there were no significant differences in biochemical tests or history of oral contraceptive use between the prolactinoma group and patients with prolonged "functional" amenorrhea (OC plus NOC groups). The lack of historical or biochemical difference between the OC and NOC subjects indicates homogeneity between groups, and does not support the existence of a "postpill" syndrome.

Adult↗
PubMed1979

Prolactin and deficient luteal function.

The possibility of prolactin-dependent subfertility was investigated in a group of 8 women, with luteal insufficiency exhibiting moderately elevated plasma prolactin (PRL) levels and/or galactorrhea. Another group of 10 normal women volunteers served as the control group. A "luteal index" was elaborated by integration of the area below the curve of plasma progesterone (P) values recorded throughout the postovulatory period. The calculated index for normal women was 177 +/- 35 (SD) expressed as [(ng/ml) x time], and the value of 107 (--2 SD) was adopted as the lower limit of normality (97.5% confidence limit). All 8 patients had luteal indexes (range 20--105) below the established limit. Therapy with bromocriptine (CB 154), 5 mg/day, suppressed PRL to normal levels and prolonged the postovulatory hyperthermic phase in 6 out of 8 women. This was accompanied by an improvement in the luteal index, and 5 women conceived. It is concluded that prolactin may interfere with normal progesterone synthesis by the corpus luteum, as demonstrated by the prompt restoration of fertility by bromocriptine treatment in women with regular cycles and inadequate luteal function.

Adult↗
PubMed1979

Seminal fluid prolactin: studies in normal subjects and in hypergonadotropic oligospermia.

A sensitive radioimmunoassay was developed for the determination of seminal plasma prolactin levels. Prolactin added to normal or oligospermic seminal plasma was fully recoverable, indicating that the seminal plasma of oligospermic patients did not contain interfering substances. A gradient between seminal plasma blood serum prolactin was found in 54 health fertile subjects. No gradient was demonstrable among 13 infertile oligospermic patients who had normal levels of serum testosterone and luteinizing hormone but elevated levels of follicle-stimulating hormone.

Follicle Stimulating Hormone↗
PubMed1978

The effect of estrogens on hypothalamic structure and function.

Data accumulated from studies of several species indicate that sex steroids are metabolized by neuroendocrine tissues in a manner analogous to that of other target tissues. Evidence that androgens or their estrogenic metabolites affect the morphology and function of the nervous system in fetal, newborn, developing, and adult rats is presented. The destruction of neural processes subsequent to the administration of large doses of estrogen to intact rats can now be added to the previously known effects on synaptogenesis, cell morphology, and function. We believe this destruction to be a form of chemical deafferentation and that it may underlie age-related hypothalamic failure and the development of multifollicular ovaries in the rat. Implications for other species are not clear at present.

Adrenal Cortex Hormones↗
PubMed1978

Effects of a single injection of estradiol valerate on the hypothalamic arcuate nucleus and on reproductive function in the female rat.

Young adult cyclic female rats were each injected with 2 mg estradiol valerate (EV) in sesame oil. Controls received an equivalent volume of sesame oil. Within 2 months after injection, most of the EV-treated animals showed persistent vaginal estrus and small polyfollicular ovaries as well as pathological changes in the hypothalamic arcuate nucleus. This pathological process was gradually progressive such that by 6 months after EV injection, the basal lateral region of the nucleus contained numerous reactive microglia, astrocytes, and degenerating elements of the neuropil. The experimental rats had elevated plasma PRL and GH concentrations which gradually diminished. Plasma estradiol concentration remained elevated 2 months after injection, while plasma LH and FSH concentrations stayed within the high and low normal range, respectively. The pituitary glands of injected animals weighed significantly more than those of controls 5.5 months after injection, but the enlarged glands did not cause hypothalamic compression. As mechanical anterior deafferentation of the medial basal hypothalamus has previously been shown to produce similar endocrine and reproductive alterations, it may be that estradiol treatment results in a functional-anatomical disconnection of the arcuate nucleus from the more anterior hypothalamic areas that regulate cyclicity. Whether this type of functional-anatomical phenomenon underlies other varieties of induced or secondary acyclicity in females remains to be determined.

Animals↗
PubMed1978

Steroid induction of gonadotropin surges in the immature rat. I. Priming effects of androgens.

Sexually immature female rats were either primed with estradiol benzoate on day 23 or given daily injections of various androgens on days 23--25. Plasma for LH and FSH determinations was collected on day 26, 5 h after an injection of progesterone. Massive gonadotropin surges were found after priming with estradiol benzoate or treatment with dehydroepiandrosterone (DHEA), delta 4-androstenedione, and testosterone, but not with ring A-reduced androgens (5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha,17 beta-diol, its 3 beta-epimer, and androsterone) or the nonaromatizable 11 beta-hydroxy- and 11-ketoderivatives of delta 4-androstenedione. Rats bearing DHEA-containing Silastic implants also produced LH surges in response to progesterone. A single injection of an antiestrogen antiserum abolished gonadotropin surges in rats primed with estradiol benzoate or DHEA and greatly reduced the accompanying uterine hypertrophy. DHEA and delta 4-androstenedione were barely uterotrophic in ovariectomized rats but sustained progesterone-induced gonadotropin surges. The results indicate that certain (adrenal?) androgens are able to induce maturation of the steroid-sensitive surge system via extragonadal aromatization, whereas their uterotrophic effect is largely mediated by the ovaries. Coordinated increased conversion of androgens at central and peripheral sites may be of physiological importance for the triggering of puberty.

Androgens↗
PubMed1978

Steroid induction of gonadotropin surges in the immature rat. II. Triggering ability of progesterone metabolites, adrenocortical hormones, and adrenocorticotropin.

Several adrenocortical steroids were tested for their ability to trigger LH release in estrogen-primed sexually immature female rats. Massive LH surges, approaching these known to be triggered by progesterone (P), followed the injection of depot ACTH1-24 and also of the adrenal steroids deoxycorticosterone (DOC) and 4-pregnen-21-ol-3,20-dione 21-acetate, but not of 5 alpha- and 5 beta-pregnan-21-of-3,20-dione, corticosterone, or aldosterone. Estrogen-primed adrenalectomized/ovariectomized rats also responded to DOC, albeit to a lesser extent. The P metabolites 5 alpha-pregnana-3,20-dione, 4-pregnen-20 alpha-ol-3-one, and 3 alpha-hydroxy-5 alpha-pregnan-20-one proved ineffective, although their triggering ability in adults was confirmed. It is concluded that adrenal P and DOC are potent activators of the gonadotropin surge system underlying pubertal ovulation and that P metabolites may acquire biological properties during sexual maturation.

Adrenal Cortex Hormones↗