Mechanisms of precocious puberty induced in male rats by pituitary grafts

Aguilar, Rafaela; Bellido, C.; Sánchez-Criado, José E.; Aguilar, E.

doi:10.1530/jrf.0.0830879

Cited by 9 publications

(7 citation statements)

References 10 publications

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“…These results confirm our initial hypothesis [4,10] concerning the existence of two mechanisms in precocious puberty induced by pituitary grafts: a PRL-dependent one when 'adult' pituitaries were used, and another LH-dependent one when 'young' pituitaries were used. This mechanism would be similar to the well-known precocious puberty induced by injections of HCG and PHSG.…”

Section: Discussionsupporting

confidence: 87%

“…Previous results [4,10] suggested that the precocious pu berty induced by a 'young' graft was not mediated by an in crease in PRL secretion, since no increased PRL plasma levels were obtained and the effect of the pituitary graft was not blocked by bromocriptine.…”

Section: Discussionmentioning

confidence: 87%

“…This effect, which is associated with an increase in plasma PRL con centration, can be blocked by bromocriptine treatment. However, precocious puberty induced in both male and female rats by grafting a pituitary gland from a 'young donor' rat (21 days old) was neither associated with increased PRL levels nor blocked by bromocriptine treatment [4,10]. This disagreement suggests the existence of two mechanisms in precocious puberty induced by a pituitary gland graft: the first is associated with the release of PRL by the graft and the second is not directly related to PRL] 10],…”

mentioning

confidence: 99%

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Luteinizing-Hormone-Mediated Precocious Puberty Induced in Female Rats by a Prepuberal Pituitary Graft

Pinilla

López²,

Gonzalez³

et al. 1989

Neuroendocrinology

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The present study analyzes the mechanism of precocious puberty induced in female rats after a ‘young’ pituitary graft (obtained from 21-day-old animals). For this purpose, the following experiments have been performed: (1) female rats were grafted or sham-operated on day 21 with a littermate’s pituitary the follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol plasma levels as well as the ovarian, uterine and adrenal weights were determined at different times after the graft; (2) female rats grafted or sham-operated on day 21 were treated with 0.2 ml of LH antiserum (LHAS) or the same volume of a normal horse serum (NHS); (3) female rats were injected on day 1 of life with 0.1 mg of estradiol benzoate or olive oil. Groups of these animals were decapitated daily between days 6 and 21 in order to measure gonadotropins and prolactin (PRL) pituitary content. Since on day 21 estrogenized females showed decreased gonadotropin content and normal PRL content, females in experiment 4 were grafted on day 21 with pituitaries obtained from control or neonatally estrogenized female rats. The results obtained showed that FSH, LH and estradiol plasma levels as well as ovarian and uterine weights increased after pituitary grafts. LHAS blocked the precocious puberty induced by the pituitary graft, and pituitaries obtained from neonatally estrogenized female rats were unable to modify the occurrence of puberty when grafted. In conclusion, this work evidences that precocious puberty induced by ‘young’ pituitary grafts was mediated by the increase in LH secretion from the graft.

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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 87%

mentioning

confidence: 99%

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Luteinizing-Hormone-Mediated Precocious Puberty Induced in Female Rats by a Prepuberal Pituitary Graft

Pinilla

López²,

Gonzalez³

et al. 1989

Neuroendocrinology

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“…Given the association between hyperprolactinemia and accelerated puberty in males, 33 plasma PRL was assayed at PND 36 for control and exposure groups with early BPS (Figure 4A). A significant increase in plasma PRL was observed in groups exposed to 0.03 and 3.0 ppm BPA ( P < 0.05), with mean difference for the 0.001-ppm EE group approaching significance ( P = 0.078).…”

Section: Resultsmentioning

confidence: 99%

Estrogen-Like Disruptive Effects of Dietary Exposure to Bisphenol A or 17α-Ethinyl Estradiol in CD1 Mice

et al. 2012

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Bisphenol A (BPA) is an endocrine disrupting chemical that is ubiquitous in wild and built environments. Due to variability in study design, the disruptive effects of BPA have proven difficult to experimentally replicate. This study was designed to assess the disruptive actions of dietary BPA exposure, while carefully controlling for known confounders. Parental CD1 mice were acclimated to defined diet containing BPA (0.03, 0.3, 3, 30, or 300 ppm) or 17α-ethinyl estradiol (EE; 0.0001, 0.001, and 0.01 ppm) and bred to produce progeny (F1) that were maintained through adulthood on the same diet as the parents. In F1 females, uterine weights were increased in all EE and the 30-ppm BPA-exposure groups, demonstrating model sensitivity and estrogen-like actions of BPA. In BPA-exposed females, no treatment-related differences were observed in parental reproductive function, or in the timing of puberty and metabolic function in female offspring. In F1 males, modest changes in body weight, adiposity and glucose tolerance, consistent with improved metabolic function, were observed. Associated with increased prolactin and increased circulating testosterone levels, balanopreputial separation was accelerated by 0.03 and 3.0 ppm BPA and anogenital distance at postnatal day 21 was increased in males by 0.03 ppm BPA. Sperm counts were also increased with 3.0 ppm BPA exposures. Overall, BPA was found to have modest, sex specific endocrine disruptive effects on a variety of end points below the established no observed adverse effect level. The dose response characteristics for many of the effects were nonmonotonic and not predictable from high-dose extrapolations.

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“…The aim of this study was to analyse the usefulness of BPS as an external sign of (Aguilar et al -1988 in press), because it had been previously reported that in this experimental model the date of BPS was modified. In order to establish adequate correlations, quantitative histological parameters (the absolute volume of the seminiferous epithelium and the spermatogenic level) were studied.…”

Section: Introductionmentioning

confidence: 99%

Balano-Preputial Separation as an External Sign of Puberty in the Rat: Correlation with Histologic Testicular Data/Balano-praeputial-Trennung als ein äußeres Zeichen der Pubertät für die Ratte: Korrelation mit histologischen Daten

et al. 2009

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Summary: In order to correlate the date of balano‐preputial separation (BPS) with the testicular development, twenty four rats were selected from an experimental design focused on the effects of pituitary grafts on puberty. Animals that presented BPS at an early age, showed a smaller volume of the seminiferous epithelium and a lower spermatogenic level than that presented BPS at a more advanced age. These data indicate that the advancement in BPS induced by pituitary grafts was not in keeping with an equivalent enhancement of testicular development. Zusammenfassung: 24 Ratten wurden für eine experimentelle Studie herangezogen, bei welcher der Zeitpunkt der Balano‐praeputial‐Trennung (BPS) mit der Hodenentwicklung zu korrelieren versucht wurde unter gleichzeitiger Berücksichtigung des Einflusses einer Hypophysentransplantation auf die Pubertät. Es zeigte sich, daß die Tiere, welche eine frühere BPS hatten, ein geringeres Volumen des Keimepithels und eine geringere Spermatogenese zeigten als jene, bei denen BPS erst in einer mehr fortgeschrittenen Phase des Lebensalters eingetreten war. Diese Daten bedeuten, daß die Vorverlegung der BPS, welche durch eine Hypophysentransplantation induziert ist, nicht in Übereinstimmung steht mit einer äquivalenten Steigerung der Hodenentwicklung.

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Mechanisms of precocious puberty induced in male rats by pituitary grafts

Cited by 9 publications

References 10 publications

Luteinizing-Hormone-Mediated Precocious Puberty Induced in Female Rats by a Prepuberal Pituitary Graft

Luteinizing-Hormone-Mediated Precocious Puberty Induced in Female Rats by a Prepuberal Pituitary Graft

Estrogen-Like Disruptive Effects of Dietary Exposure to Bisphenol A or 17α-Ethinyl Estradiol in CD1 Mice

Balano-Preputial Separation as an External Sign of Puberty in the Rat: Correlation with Histologic Testicular Data/Balano-praeputial-Trennung als ein äußeres Zeichen der Pubertät für die Ratte: Korrelation mit histologischen Daten

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