The effect of estrogens on hypothalamic structure and function

Naftolin, Frederick; Brawer, James R.

doi:10.1016/s0002-9378(78)80010-6

Cited by 50 publications

(12 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This study is in agreement with the hypothesis that the ovarian changes after neonatal DES exposure are secondary to the abnormal endocrine milieu in which the ovary develops (Goomer et al, 1977;Hailing, 1992). The primary events that lead to aberrant development of the hypothalamic-pituitary system and anovulatory sterility in adult female mice neonatally treated with DES may be a result of estrogen on the maturation process of the luteinizing hormone-releasing hormone (LH-RH) neurons (Naftolin and Brawer, 1978;Ojeda and Urbanski, 1988 hydroxyprogesterone) and partly gonadotropin independent ([ 3 H]progesterone, [ 3 H]testosterone). This pattern is different from that in control ovaries (only [ 3 H]-17a-hydroxyprogesterone gonadotropin independent), which could be related to the described morphological differences in ovarian tissue compartments.…”

Section: Discussionsupporting

confidence: 89%

Steroid synthesis in ovarian homogenates from hypophysectomized adult female mice treated with diethylstilbestrol in neonatal life

Halling

1992

Journal of Toxicology and Environmental Health

View full text Add to dashboard Cite

Eight-week-old female NMRI-mice treated with 5 micrograms diethylstilbestrol (DES) or vehicle (olive oil) from d 1 to 5 after birth were hypophysectomized or sham operated. Thirty days after the operation, homogenates were prepared from the ovaries and incubated at 37 degrees C in the presence of [3H]pregnenolone for 1 h. In parallel experiments ovaries were taken for histology. In control ovaries regressing corpora lutea were still present 4 wk after hypophysectomy (Hx). Ovaries from DES females had no corpora lutea, but showed degeneration of the pre-Hx hypertrophic interstitial tissue. Steroids synthesized during the incubation were extracted and separated in a two-dimensional thin-layer chromatography system. After Hx, the amount of extractable [3H]testosterone, [3H]progesterone, and [3H]androstenedione recovered from homogenates of vehicle-treated females increased, but the amount of recovered [3H]-17 alpha-hydroxyprogesterone was not significantly altered. In contrast, in DES-treated females Hx significantly decreased levels of [3H]androstenedione and [3H]-17 alpha-hydroxyprogesterone, but did not affect [3H]progesterone or [3H]testosterone. The persistent difference in steroid synthetic activity after Hx could be linked to the difference in morphology between different ovarian tissue compartments of control and DES-treated females.

show abstract

Section: Discussionsupporting

confidence: 89%

Steroid synthesis in ovarian homogenates from hypophysectomized adult female mice treated with diethylstilbestrol in neonatal life

Halling

1992

Journal of Toxicology and Environmental Health

View full text Add to dashboard Cite

show abstract

“…Our previous studies have shown that, in rats with this syndrome, luteinizing hormone (L.H) secretion continues and is responsive to preoptic area (MPO) stimu lation and luteinizing hormone releasing hormone (LH-RH) analog administration [4]. Other authors have reported similar findings in constant estrus induced by neonatal an drogen administration and constant light exposure [2,5,17,21], Based upon these findings, and in keeping with the idea that the arcuate nucleus exercises a modulating effect upon LH-RH secretion, we proposed that these conditions re present failure of hypothalamic control over LH-RH secre tion rather than loss of LH-RH-containing fibers reaching the median eminence (ME) [2,20], To test this hypothesis we have assessed the number and morphology of LH-RHcontaining fibers in the mediobasal hypothalamus (MBH) during induced constant estrus/diestrus and compared the …”

supporting

confidence: 71%

Reproductive Failure due to Experimentally Induced Constant Estrus Does Not Alter the LH-RH Fiber Density in the Median Eminence of the Rat

et al. 1986

View full text Add to dashboard Cite

The effects of anterior hypothalamic deafferentation on luteinizing hormone releasing hormone (LH-RH) fiber density in the mediobasal hypothalamus (MBH) were compared to those of a number of nonsurgical treatments which give rise to anovulatory sterility (injections of estradiol valerate, exposure to constant light, or neonatal androgen administration) in the female rat. All of the treatments used (surgical and nonsurgical) disrupted the normal 4-day pattern of estrous cyclicity. Bilateral anterior hypothalamic deafferentation markedly reduced the packing density of LH-RH fibers in the MBH. Unilateral deafferentation reduced the number of fibers on the ipsilateral side of the MBH by 31–64% and on the contralateral side by 15–40%. In contrast, none of the three nonsurgical treatments had any significant effect on the LH-RH fiber density. Electron microscopic examination revealed no morphologic, or distribution differences in MBH LH-RH fibers between control females and animals rendered anovulatory by the nonsurgical experimental procedures. These results demonstrate that estrogen, androgen, and constant light induced anovulatory sterility are not associated with any overt change in the number or morphology of LH-RH immunoreactive fibers in the MBH, suggesting that the primary lesion responsible for the failure of normal estrous cyclicity in such animals resides in the systems responsible for regulating the activity of the LH-RH neurons rather than in the LH-RH neurons themselves.

show abstract

“…In the rat, sexual differentiation in the brain involves neuronal modification by sex steroids present before and during the week after birth [32,37], Current evidence sug gests that circulating androgen is converted by cytoplasmic enzymes into estrogen which modifies the functional charac teristics of the hypothalamus [38]. Independent of the gene tic sex, if estradiol is present, a male pattern of tonic secre tion develops but if absent, the brain retains a female cyclic LH release pattern.…”

Section: Discussionmentioning

confidence: 99%

“…However, the presence of perinatal estrogens or androgens has been related to a number of permanent structural modi fications of different hypothalamic and limbic regions; e.g. cell nuclear volume, observable at the light microscopic lev el [5,29,32,37], Raisman and Field [37] demonstrated that the striatal portion of the preoptic area has more synapses from nonamygdaloid sources on dendritic spines in female than in male rats, and the proportion of these synaptic con tacts can be modified by androgen during the critical devel opmental period. Toran-Allerand [42] stimulated the neuritic outgrowth of specific hypothalamic levels by the addition of estrogens to the medium of cultures of newborn mouse preoptic/hypothalamic area while neutralization of estro gen in the nutrient retarded outgrowth of these same levels.…”

Section: Discussionmentioning

confidence: 99%

“…The hypothalamus has been implicated as the cen tral nervous system site for both the differentiating [2,9] and feedback effects of gonadal steroid hormones [30]. Recent ly, a number of studies have localized cellular differences in estrogen action in the hypothalamus which may underlie the morphological, physiological and behavioral differ ences found between males and females and between nor mal rats and animals hormonally manipulated at birth [12,32]. Because hypothalamic LHRH is directly involved in the control of gonadotropin secretion and in mediating sexual behavior, it is conceivable that perinatal estrogen perma nently affects hypothalamic mechanisms responsible for LHRH synthesis and release in adulthood.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Neonatal Estrogen Affects Preoptic/Anterior Hypothalamic LHRH Differently in Adult Male and Female Rats

et al. 1984

View full text Add to dashboard Cite

When administered during the critical perinatal period, estrogen permanently modifies both male and female reproductive function. This study evaluated the influence of exogenous estrogen administered during this time on the hypothalamic LHRH content and on gonadotropin secretion in adult male and female rats. LHRH content in the preoptic-anterior hypothalamic (PO/AH) and midhypothalamic (MH) areas of neonatally estrogenized rats (1 mg on postpartum day 2) and of control male and female rats during the estrous cycle was determined by radioimmunoassay between 80 and 90 days of age. LHRH content was significantly greater in the PO/AH of neonatally estrogenized females than in estrogenized males whereas no differences in LHRH content of the PO/AH existed between control male and female rats. Neonatal administration of estrogen resulted in increased LHRH content in the MH of female rats and decreased LHRH content in male rats, as in the PO/AH; however, these differences were less marked in the MH and not statistically significant. The marked increase in serum LH concentration present in control cycling females in proestrus was abolished by neonatal estrogen treatment. Exposure to neonatal estrogen reduced FSH concentrations in males. The data are consistent with the concept that the hypothalamic-pituitary system is modified by estrogen circulating during the period of sexual differentiation. LHRH synthesis and release appear to be directly modified by neonatal estrogen. The effects of neonatal estrogen treatment in the PO/AH and MH areas may possibly involve two disparate types of alterations of developing LHRH neurons which modulate gonadotropin secretion in the adult rat.

show abstract

The effect of estrogens on hypothalamic structure and function

Cited by 50 publications

References 28 publications

Steroid synthesis in ovarian homogenates from hypophysectomized adult female mice treated with diethylstilbestrol in neonatal life

Steroid synthesis in ovarian homogenates from hypophysectomized adult female mice treated with diethylstilbestrol in neonatal life

Reproductive Failure due to Experimentally Induced Constant Estrus Does Not Alter the LH-RH Fiber Density in the Median Eminence of the Rat

Neonatal Estrogen Affects Preoptic/Anterior Hypothalamic LHRH Differently in Adult Male and Female Rats

Contact Info

Product

Resources

About