Receptor Estrogen Complex in the Nuclear Fraction of the Pituitary and Hypothalamus of Male and Female Immature Rats

Jh, Clark; Ps, Campbell; Ej, Peck

doi:10.1159/000122091

Cited by 48 publications

(9 citation statements)

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“…It must be pointed out that receptor proteins binding oestrogens have been found to be present in both structures (McGuire 8c Lisk 1969;Clark et al 1972;Friend 8c Leavilt 1972;Ginsburg et al 1972;Kulin 8c Reiter 1972;Luttge 8c Whalen 1972;Kato 1973). It is obvious that if one accepts the view that the feedback effect of oestrogens is mainly exerted at hypothalamic level.…”

Section: Discussionmentioning

confidence: 99%

Effect of Ovariectomy on Oestrogen-Sensitive Feedback Elements

Zanisi

Martini

1975

Acta Endocrinologica

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Serum LH and FSH were measured by radioimmunoassay in untreated and oestrogen-treated ovariectomized rats. The animals were sacrificed 7, 14, 21 and 28 days after ovariectomy. Oestradiol benzoate was administered in the daily dose of 50 \g=m\gon the 2 days preceding sacrifice. It has been found that oestrogens exert a strong inhibitory effect on the release of LH, as evidenced by a decrease in serum titers of the hormone. Oestradiol suppressed LH almost completely in animals with both low (7 or 14 days post-ovariectomy), and high levels of serum LH (21 or 28 days post-ovariectomy). Oestradiol failed to totally suppress serum FSH at any post-castration time considered. Moreover, the inhibitory effect of oestradiol on FSH release decreased as post-castration time increased. These data suggest that the feedback mechanisms which control the secretion of LH and those which control the secretion of FSH are substantially different.It has been previously reported that, in the female rat, castration is followed by a rapid increase of serum levels of FSH (Zanisi 8c Martini 1975) and by a slow and delayed elevation of serum levels of LH (Gay 8c Midgley 1969;Yamamoto et al. 1970; Blackwell 8c Amoss 1971). Serum LH does not vary up to 7 days following ovariectomy. After this time, a rapid increase is observed, with maximum values being reached on days 28 and 35 (Zanisi 8c Martini 1975). It is generally accepted that ovariectomy induces these changes in gonado¬ trophin secretion because oestrogens are eliminated from the general circulation (Martini et al 1968). The hypothesis may consequently be formulated that the retarded response of serum levels of LH is linked to a change of the threshold

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Section: Discussionmentioning

confidence: 99%

Effect of Ovariectomy on Oestrogen-Sensitive Feedback Elements

Zanisi

Martini

1975

Acta Endocrinologica

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“…To distinguish between nonspecific and specific binding, tissue slices were incubated concurrently with the same concentration of 3 H-prostaglandin plus 100-fold excess of the appropriate nonradioactive prostaglandin. The difference between the uptake of 3 H-prostaglandin in the absence and presence of nonradioactive prostaglandin represents the specifically bound prostaglandin (U, 8,9). This method was used to measure specific binding of PGEi and PGF 2a human myometrium and monkey endometrium and myometrium, in pregnant hamster myometrium and in uteri from ovariectomized, steroid-treated hamsters.…”

Section: Determination Of Specifically Bound Prostaglandinmentioning

confidence: 99%

Prostaglandin Receptors in the Human, Monkey and Hamster Uterus

Wakeling¹,

Wyngarden²

1974

Endocrinology

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An in vitro tissue slice incubation system has been used to measure uptake and binding of 3 H-labeled prostaglandins by uterine tissues from the human, monkey and hamster. Specific binding of prostaglandin Ei (PGEi) and P G F 2 Q was demonstrated in rhesus monkey myometrium, but not endometrium, and in human myometrium. Specific binding of PGE 2 but not PGF, a was present in hamster uterus throughout the estrous cycle. Variations in prostaglandin specific binding during the estrous cycle, and in pregnancy of the hamster, and demonstration of prostaglandin concentrative capacity of the hamster uterus, were indicative of the presence of true prostaglandin receptors in the uterus. Quantitative estimates of PGE, binding in the hamster uterus gave values for the association constant of 5.8 and 16.4 x 10 9 M~! and values for receptor concentration of 3.7 and 4.1 x 10" 12 moles/100 mg tissue for whole uterus and myometrium, respectively. Relative affinities of some prostaglandins for PGE, binding sites in the hamster uterus were 16,16-dimethyl PGE, = PGE, = PGE 2 > 15(S)15-methyl PGE, methyl ester = 13,14-dihydro PGE, = PGA, = PGE, methyl ester $> PGF 2a = 15-keto PGE,. Treatment of ovariectomized hamsters with estradiol decreased PGE, and PGF 2a specific binding in the uterus in a dose-dependent manner. Progesterone increased b'oth PGE, and PGF 2a specific binding. (Endocrinology 95: 55, 1974) R ECENT reports .from this laboratory have demonstrated the presence of prostaglandin receptors in the hamster uterus (1) and in the rabbit oviduct (2). In vitro studies on the nature of prostaglandin Ei (PGEx) receptor in the hamster uterus (3) have shown that the PGE! receptor is located in a membrane fraction of the uterus and is stabilized by association with its ligand. The receptor is at least, in part, a protein and the binding is irreversible in vitro. The relative lability of prostaglandin specific binding in broken-cell preparations (3) has led us to further study of the nature of prostaglandin binding in intact tissue slices of the uterus. In this paper we report studies of prostaglandin uptake by monkey and human uterus, quantitative measurements of the PGEj receptor in the hamster uterus, and changes in prostaglandin specific binding in the hamster uterus in response to changes in physiological state and treatment with ovarian steroids.

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“…1980 Accepted: June 24. 1980 and that fewer nuclear estrogen receptor complexes accu mulate in male than in female hypothalamus after estradiol injection [9] …”

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confidence: 99%

A Sex Difference in the Progestin Receptor System of Guinea Pig Brain

1980

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Female guinea pigs are more sensitive than males to the lordosis-promoting effects of sequential estradiol-progesterone treatment. This study explored a possible cellular basis for this reduced sensitivity. Cytoplasmic progestin receptor concentrations were determined using a [³H]R5020 binding assay for a dissection of brain tissue which included the hypothalamus, preoptic area and septum (HPS) from male and female guinea pigs 40 h after administration of estradiol ben-zoate (EB). Male guinea pigs injected with 10 μg EB have a progestin binder in cytosol from HPS and cerebral cortex that is similar to that in females on the basis of apparent dissociation constant and steroid specificity. Injection of either 1.6 or 10 μg EB caused a larger increase in the concentration of cytoplasmic progestin binding in female HPS compared to the same dose in males. A 10 μg EB injection induced a concentration of progestin binding in male hypothalamus not significantly different from that induced in female hypothalamus by a 1.6 μg EB injection (a dose that consistently facilitates sexual recepivity in females when followed 40 h later by 0.5 mg progesterone). Despite the induction by EB of a behaviorally-sufficient concentration of cytoplasmic progestin receptors, fewer males (3/10) than females (8/10) responded to EB (10 μg)-progesterone treatment with the expression of lordosis. Finally, using a nuclear progestin receptor [³H]R5020 exchange assay, we found that male guinea pigs injected with 10 μg EB accumulated a slightly lower concentration of progestin receptors in HPS cell nuclei 4 h after a 0.5 mg progesterone injection than similarly-treated females. Therefore, male guinea pigs show decreased induction of cytoplasmic progestin receptors in HPS after estradiol injection, and a decreased cell nuclear accumulation of these receptors after progesterone injection compared to females. We conclude that this sex difference in the progestin receptor system is insufficient to account, in itself, for the sex difference in behavioral sensitivity to estradiol and progesterone.

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Receptor Estrogen Complex in the Nuclear Fraction of the Pituitary and Hypothalamus of Male and Female Immature Rats

Cited by 48 publications

References 0 publications

Effect of Ovariectomy on Oestrogen-Sensitive Feedback Elements

Effect of Ovariectomy on Oestrogen-Sensitive Feedback Elements

Prostaglandin Receptors in the Human, Monkey and Hamster Uterus

A Sex Difference in the Progestin Receptor System of Guinea Pig Brain

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