Changes in the concentrations of testosterone and androstenedione in the plasma and testis of the guinea-pig from birth to death

Rigaudière, N; Pelardy, G; Robert, Alain; Delost, P

doi:10.1530/jrf.0.0480291

Cited by 66 publications

(37 citation statements)

References 23 publications

(25 reference statements)

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“…A combination of adrenal response [Rigaudière et al, 1976] including the amount of hormones secreted and the sen sitivity of the sex accessory gland may prove to be the cause of the difference in the rat and guinea pig. Furthermore, the adrenal gland in the guinea pig has the highest unit weight and cortex-to-medulla ratio among mammals as well as a smaller unit testis weight than the rat, an indication of the rela tive role of the testis and adrenal gland in their function in the male accessory glands [Rivarola et al, 1965],…”

Section: Discussionmentioning

confidence: 99%

Structural study of the involution of the seminal vesicles of the guinea pig following orchiectomy

Tse¹,

Wong²

1980

Cells Tissues Organs

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The involution of the seminal vesicles of the guinea pig after castration has been studied by electron microscopy. The epithelial cells decreased in size and the basal lamina became more tortuous after castration. The most obvious changes occurred in the amount and configuration of the granular endoplasmic reticulum (GER). Besides a general decrease in GER, there was also a change from predominantly parallel arrays to a spiral or concentric arrangement, followed by dilation and vesiculation of the GER. There was an increase in glycogen and lipid contents of the epithelial cells. Large aggregates of glycogen particles were found associating with dilated GER and lipid droplets and these glycogen particles increased with the progression of involution. The Golgi complex became smaller and a slight increase in the number of autophagic and lysosomal granules was observed. Secretory granules decreased in size and quantity but persisted even at 4 months after the operation. The postcastration response of the seminal vesicles of the guinea pig was slow and incomplete and was different from that of the rat and mouse, where involution was virtually completed within 3 weeks. The slow and incomplete regression is not clear, but is believed to be related to the function of the adrenal glands which may provide the extratesticular source of hormone to partially maintain the gland after castration.

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Section: Discussionmentioning

confidence: 99%

Structural study of the involution of the seminal vesicles of the guinea pig following orchiectomy

Tse¹,

Wong²

1980

Cells Tissues Organs

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“…The following work is part of a more general study on the level of androgens throughout the life of the guinea-pig. The results of perinatal, pubertal, adult and senescent periods have been reported previously (Rigaudière et al 1976;Pelardy 8c Delost 1978).…”

mentioning

confidence: 59%

The Androgens in the Guinea-Pig Foetus Throughout the Embryonic Development

Rigaudière

1979

Acta Endocrinologica

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Testosterone (T) and dihydrotestosterone (DHT) content and concentration were measured by radioimmunoassay in plasma, gonads, adrenals, and sexual ducts of 235 male and 214 female guinea-pig foetuses at various stages of gestation after gonadal and adrenal differentiation occurred.In the male foetus, a sharp increase in the content and concentration of T and, to a lesser degree of DHT, is observed in the testis, the plasma and the ducts at the time of sexual differentiation between days 28 and 36. Thereafter androgen concentrations in these tissues decrease and rise again after day 52. In the female foetus, levels of T and DHT in the ovary are low throughout foetal life and do not account for the relatively high concentrations found in the plasma; in sexual ducts, T concentrations decrease at the time of differentiation. DHT levels are low at every stage. In both sexes, T and DHT are present in the adrenal. No sexual dimorphism is observed in the evolution of T and DHT adrenal content and concentration.In the guinea-pig, the chronology of sexual differentiation and the role of foetal gonads in the development of the genital tract have been precisely stated (Black 8c Christensen 1969; Price et al. 1975); the duration of intrauterine life is about 68 days; gonadal and adrenal differentiation occurs on day 22 and that of ducts and the genital tract on day 29. Moreover, in this rodent the different stages in maturation of the hypothalamic-pituitary-gonad axis have been well documented (Brown-Grant 8c Sherwood 1971; Donovan et al. 1975). However, quantitative data on the guinea-pig concerning end-

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“…The pubertal period in the guinea-pig can be divided into two parts Rigaudière et al, 1976): a prepubertal period, from Days 16 to 60 during which a linear increase in plasma testosterone concentration occurs according to the regression equation y = 1-08* + 4-7 (r = 0-96; = 60), and a postpubertal period from Days 60 to 90 when the levels of testosterone remain stable. The present results show that the evolution of MCR (1/24 h) and testosterone production rate during puberty also take place in two stages.…”

Section: Discussionmentioning

confidence: 99%

“…In the guinea-pig (Robert & Delost, 1975 ; Rigaudière, Pelardy, Robert & Delost, 1976), plasma and testicular androgens rise significantly between Day 16 and Days 50-60, when puberty occurs. During this time, a linear increase occurs in plasma and testicular concentrations of testosterone as well as in body, testis and seminal vesicle weight.…”

Section: Introductionmentioning

confidence: 99%

Peripheral metabolism of testosterone during puberty in the male guinea-pig

Robert¹,

Delost²

1978

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Variations in the metabolic clearance rate and the production rate of testosterone during puberty in the male guinea-pig were established by single injection and constant infusion methods. Similar results were obtained; MCR (1/24h) increases from Day 20 to Day 70 and then stabilizes between Days 70 and 90 to levels comparable to those of a 6-month-old adult. MCR as 1/24 h/100 g decreases steadily between Days 20 and 60. The evolution of the testosterone production rate (PR: ng/24 h) is characterized by a marked rise between Days 20 and 70, and then a decrease up to Day 90, continuing until 6 months. PR as ng/24 h/100 g increases between Days 20 and 40, remains stable until Day 70, then decreases. Testosterone half-life is stable throughout the pubertal period. The rate of conversion of testosterone to androstenedione remains stable except for a rise between Days 50 and 60. We conclude that the increase in testosterone concentrations during puberty is due to a rise in the production rate and not to a decrease of clearance rate.

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Changes in the concentrations of testosterone and androstenedione in the plasma and testis of the guinea-pig from birth to death

Cited by 66 publications

References 23 publications

Structural study of the involution of the seminal vesicles of the guinea pig following orchiectomy

Structural study of the involution of the seminal vesicles of the guinea pig following orchiectomy

The Androgens in the Guinea-Pig Foetus Throughout the Embryonic Development

Peripheral metabolism of testosterone during puberty in the male guinea-pig

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