The onset of female puberty: underlying neuroendocrine mechanisms

Ojeda, Sergio R.; Smith, Sheryl S.; Urbanski, Henryk F.; Aguado, Luis I.

doi:10.1016/b978-0-444-90377-8.50010-7

Cited by 17 publications

(9 citation statements)

References 213 publications

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“…Newborn animals were kept with their mothers until time of killing or weaned at day 21. The animals were killed by decapitation in groups of six on postnatal day 5,8,12,16,20, and 24 and thereafter at 2-d intervals until day 62.…”

Section: Methodsmentioning

confidence: 99%

“…Using hypothalamic explants from male rats, it has been shown that the frequency of pulsatile GnRH secretion in vitro was low on day 15 (i.e., before weaning) whereas an increase of nearly twofold occurred on day 25 (i.e., soon after weaning) (12,17,18). In a recent study, it was shown that GnRH mRNA levels were low in both male and female rats in the infantile period (days [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and elevated in the juvenile and peripubertal periods (days 30-60) (19).…”

Section: Introductionmentioning

confidence: 99%

“…Although the ontogeny of hormone production postnatally is well defined, the intricacies of the central mechanisms underlying the ontogenetic changes are now being unraveled (for reviews see references [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Reproductive ability in the male rat is achieved around postnatal day 50 when testicular spermatogenesis occurs (4,5,8,9). Spermatogenesis is brought about by increasing levels of gonadotropins in the circulation and adult levels of testicular androgen (4,8,9).…”

Section: Introductionmentioning

confidence: 99%

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Prepubertal increases in gonadotropin-releasing hormone mRNA, gonadotropin-releasing hormone precursor, and subsequent maturation of precursor processing in male rats.

Dutlow¹,

Rachman²,

Jacobs³

et al. 1992

J. Clin. Invest.

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Changes in gonadotropins and gonadal steroids during sexual maturation in rats and humans are well documented but little is known about hypothalamic gonadotropin-releasing hormone (GnRH) gene expression in relation to these events. This study measured hypothalamic proGnRH mRNA, GnRH precursor, and fully processed GnRH from postnatal day 8 until day 62 in male rats. GnRH precursor increased on day 22, reached a peak on day 24, declined on day 25 and returned to infantile levels by day 28. A secondary rise in precursor occurred at about day 40 when testosterone levels increased. GnRH mRNA increased on day 22 and remained elevated over the study period to day 26. GnRH increased on day 24 and remained at this level until a secondary rise occurred coincident with the testosterone rise at about day 40. The ratio of GnRH precursor to GnRH was high until day 24 and was low from day 26 onwards, reflecting a maturation of the processing enzyme system between these 2 d. Thus, an abrupt increase in GnRH gene transcription (mRNA) occurs early in juvenile male rats (day 22), well before the onset of puberty. An increase in GnRH precursor accompanies these early changes and this is followed by the maturation of processing as evidenced by the rapid decline of precursor and increase in GnRH from day 24 onward. (J. Clin. Invest. 1992.90:2496-2501

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Prepubertal increases in gonadotropin-releasing hormone mRNA, gonadotropin-releasing hormone precursor, and subsequent maturation of precursor processing in male rats.

Dutlow¹,

Rachman²,

Jacobs³

et al. 1992

J. Clin. Invest.

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show abstract

“…Além destas alterações, este modelo de diabetes produz também resistência à insulina (BLONDEL, 1990;KERGOAT, 1985;SERRADAS, 1993; A respeito da puberdade em ratos sabe-se que a capacidade reprodutiva é atingida por volta do 50º dia de vida (7ª semana) quando se inicia a espermatogênese nos testículos. A espermatogênese é produzida por um aumento dos níveis de gonadotrofina na circulação e nos níveis de andrógeno testicular nos ratos adultos (FOSTER et al, 1985;KETELSLEGERS et al, 1978;OJEDA et al, 1984;PAYNE et al, 1977 Outro importante evento desencadeado na puberdade é o aumento da amplitude do pulso de secreção do hormônio de crescimento (GH), o que é estimulado pela ação da testosterona e estradiol na hipófise. O GH é necessário para o crescimento linear normal e também afeta muitos aspectos do metabolismo corporal, sendo classificado como anabólico, lipolítico e diabetogênico (THORNER et al, 1988).…”

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